affects large numbers of persons with diabetes in the pendent diabetes mellitus (NIDDM) 50.2%, insulin number of demographic and diabetes-related factors. …

Chapter 12

Disability in Diabetes
Thomas J Songer, PhD
SUMMARY

he public health impact of diabetes can be evaluated from a number of perspectives, one of which is the morbidity associated with the disease Disability is a broad-based concept that often illustrates this morbidity Disability affects large numbers of persons with diabetes in the United States, with estimates ranging from 20-50 of the diabetic population Persons with diabetes, in general, report rates of disability that are substantially higher than those reported by the general US population Reported activity limitations non-insulin-dependent diabetes mellitus NIDDM 502, insulindependent diabetes mellitus IDDM 423, nondiabetic, 161 and restricted activity days NIDDM, 224; IDDM, 213; nondiabetic, 103 were two to three times higher among persons with diabetes surveyed in the 1989 National Health Interview Survey NHIS Persons with IDDM from the Childrens Hospital of Pittsburgh CHP IDDM Registry were seven times more likely to report work disability than their nondiabetic siblings 324 versus 46 Moreover, the largest impact of disability in the diabetic population appears to be in the most severe forms of disability,
including being unable to work Disability in persons with diabetes is influenced by a number of demographic and diabetes-related factors Impairments reported by diabetic persons increase with age for both NIDDM 18-44 years, 45 report activity limitations; 45-64 years, 55; 65 years, 60 and IDDM persons cumulative incidence of work limitations at age 30 years, 10; age 45 years, 48

Disability is more common in minority groups black females, 574 report activity limitations; black males, 584; white females, 516; white males, 471 Disability appears to affect persons with NIDDM, particularly those using insulin 635 report activity limitations, more than persons with IDDM 429 report activity limitations Presence of the late complications of diabetes appears to be a major determinant for disability The consequences of disability in the diabetes population are extensive Disabled IDDM subjects have lower rates of employment than those not disabled 49 not working versus 12 and higher rates of absenteeism 138 days per year versus 30 per year Reported income levels are also lower for IDDM subjects developing disability Disabled persons with diabetes use health care services more frequently than
those not limited in activity 324 were hospitalized in the past year versus 132 The average number of physician visits among persons seeing a physician was 139 per year for persons limited in activity, compared with 65 visits per year for those not limited Limitation in personal care activities of daily living ADLs are more common among diabetic than nondiabetic individuals 1989 NHIS, NIDDM: 49, IDDM: 88, nondiabetic: 23 Not surprisingly, disabled persons rate their general health status at lower levels than those not disabled Diabetic persons reporting activity limitations in the 1989 NHIS were 10 times more likely to rate their health as poor 317 versus 36 than were persons not limited in activity

INTRODUCTION

Disability is a major social, economic, public health, and political issue confronting society today Estimates of the number of disabled persons in the United States vary greatly, ranging from 27 million to 35
259

million to 49 million1-3 Disability is associated with an increased likelihood for hospitalization, institutionalization, and loss of economic self-sufficiency and normal role behaviors4,5 In addition, some persons with disabilities face barriers
in the work environment and difficulties in gaining access to public facilities6 These circumstances, together, greatly di-

minish the quality of life of those affected2,4 Chronic diseases are a major determinant of disability7 Diabetes is a chronic disease in which many individuals can lead normal and productive lives Other persons, though, face impairments and limitations related to their diabetes that influence their meaningful participation in normal activities of everyday life A review of the prevalence of disability in the diabetes population and the characteristics of these people is the focus of this chapter

Figure 121 Active pathology is defined by Nagi as some type of interference in the normal processes of the organism, such as the onset of disease This pathology may lead to an impairment an anatomical, physiological, mental, or emotional loss or abnormality Impairments, though, may arise independent of a pathology Impairments may then exert their effects in terms of functional limitations a limitation in functioning or performance at the individual level, eg, a problem in seeing, hearing, walking, or reaching, or in terms of a disability a limitation in performing
socially defined roles, eg, self-care or work In 1980, Wood developed a framework for the World Health Organization that identified disability as encompassing impairments, disabilities, and handicaps11 Impairment in this case denoted any loss or abnormality in physiologic or anatomic structure or function Disability indicated any restriction or inability resulting from an impairment to perform an activity in the manner considered normal for that individual Handicap was defined as any disadvantage resulting from an impairment or disability that limits the fulfillment of normal role behavior for the individual

DEFINITION OF DISABILITY
Unlike most clinical measures associated with diabetes, the definition of disability as it applies to persons with diabetes, as well as persons in the general population, is multidimensional Disability can be defined quite narrowly or quite broadly There is currently no standard definition used in the literature Very early on, disability was defined solely by the presence of a physical disability, such as the loss of a limb The work of two individuals, though, moved the discussion beyond physical disabilities and into a broader domain Both Saad Nagi
and Philip Wood described disability in terms of its impact on the individual physical, medical, anatomical, and emotional, and its impact on lifestyles These are, in turn, mediated by the environment and family situation in which the person lives In the late 1960s and early 1970s, Nagi outlined disability in terms of four closely related views: pathology, impairment, functional limitation, and disability810 The relationship among these views is shown in
Figure 121

SPECTRUM OF DISABILITY
As outlined above, the spectrum of disability is wide Moreover, disability is often distinguished by the interaction between individuals and their environment Not every impairment results in disability or handicap Individuals with similar conditions can differ in the severity of their impairment and their ability to meet normal role expectations due to the influence of the environment12 Some will have family situations that enable them to overcome social barriers Others will use equipment to overcome physical barriers The 1990 Americans with Disabilities Act13 aspires to reduce some of the access and employment barriers that disabled persons face In summary, the impact or severity of disability
is variable The influence may be permanent or temporary It may affect the ability to work and the ability to enjoy other life activities It may affect the use of health care services and the patterns of health insurance coverage3 Persons may be limited in self-care activities such as eating, bathing, and dressing, or they may face difficulties in moving around, lifting objects, and walking up and down stairs Disability may change the income levels of those affected, influence the use of social programs, or prejudice the decisions of individuals living with some uncertainty of what lies in their futures3,4
260

The Framework of Disability

Normal state

Pathology

Impairment

Functional limitation

Disability

Source: References 8-10

Table 121

Some Examples of the Disability Framework and Diabetes
Pathology Impairment
Onset of diabetes

Functional limitation

Disability

Worry over complications Hypoglycemia Diminished Slow No work until blood judgment reaction time glucose is raised Onset of proliferative Diminished Cannot drive Difficult to go out retinopathy vision at night after dark

tion-based survey that includes questions on disability, among other health issues The
primary measures of disability in the survey are activity limitations due to impairments or health problems and restricted activity days Activity limitations are categorized into four groups14: 1 unable to perform major activity, such as going to school, work, housekeeping, or in the elderly ADLs; 2 limited ability to perform major activity; 3 limited in activity, but not in major activity; and 4 not limited Disability days are also assessed in the noninstitutionalized population A disability day is defined as a day on which a person has to reduce his/her usual activity because of illness or injury14 Four types of disability days are defined in the NHIS: 1 bed days, 2 work loss days in the currently employed, 3 school loss days among children, and 4 total restricted activity days Further disability measures are assessed in subgroups of the population Limitations in the ability to work are asked of all adults age 18-69 years Difficulties in the ADLs eg, eating, bathing, dressing, shopping, doing housework are asked of persons reporting activity limitations and the elderly Diabetes is determined in the NHIS by asking persons if they have ever been told by a doctor that they have
diabetes For persons reporting activity limitations, the condition that caused it is also queried In 1989, a supplement on diabetes was included in the NHIS to learn more about diabetes screening, current treatment regimens, diabetes complications, and risk factors for diabetes15,16 The supplement also provided information to determine whether the respondents had IDDM or NIDDM Subjects with IDDM were defined by age 30 years at onset of diabetes, continuous use of insulin since diagnosis, and having a desirable body weight 120 of normal Persons with NIDDM were defined as all other persons with diabetes who did not have gestational diabetes or report pre-, potential, or borderline diabetes

DIABETES AND DISABILITY
Diabetes is likely to be associated with disability through a number of processes, a few of which are outlined in Table 121 For example, a sense of uncertainty about the future is evident in some persons at the onset of the disease and throughout life The acute complications of diabetes might be characterized as temporary impairments and may be associated with some limitation in physical and social performance The most common scenario is that impairments, limitations, and
disabilities will result from the development and progression of the chronic complications of diabetes

SOURCES OF DISABILITY DATA

Despite the resourcefulness of the disability frameworks, it has been difficult to incorporate all of the concepts into research and surveys of the population Most surveys assess disability in one or more of the following terms: a presence of a condition or diagnosis, b ability to get around mobility or take care of oneself, c ability to work, and d eligibility for government disability programs The federal government has been the primary source of data describing the epidemiology of disability associated with diabetes Surveys by the National Center for Health Statistics NHIS, the Census Bureau Survey of Income and Program Participation, or SIPP, and the Social Security Administration Disability and Work Survey have all assessed disability on a regular basis in some form, although each has used different survey instruments

SURVEY OF INCOME AND PROGRAM PARTICIPATION
The US Census Bureau reports on the disability status of the population in periodic panels of the annual SIPP The SIPP assesses the economic situation of households and persons in the
United States, providing information useful for evaluation of present and future government programs 17 Various types of disability measures have been assessed in the panels to the SIPP These include: Limitations in sensory or physical functioning
261

NATIONAL HEALTH INTERVIEW SURVEY
The National Center for Health Statistics reports on the characteristics of disability in the NHIS, a popula-

Difficulty with ADLs Presence of specific mental, cognitive, or developmental conditions Presence of conditions that limit work, housework, or school activity Receiving disability-related benefits Use of mechanical aids The contribution of specific health conditions to disability status has not been studied in much detail in the SIPP The few questions in this area have focused on identifying the specific conditions that caused work disability, physical limitation, or limitation in the ADLs or Instrumental Activities of Daily Living IADLs3,17 Diabetes was included as one of 30 different conditions that respondents could identify as the cause of the respective disability

Occupational disability–able to work regularly, but not full time, or at the same kind of job Secondary work
limitations–able to work regularly, full time at the same job as before disability, but limited in kind and/or amount of work

LIMITATIONS OF US GOVERNMENT DATA
In general, the prevalence of disability is presented adequately in the surveys outlined above Information is available on the number of diabetic persons disabled, the type of disability present, and the number of work-days lost As will be noted below, each survey has also shown the impact of disability to be more profound in the diabetic population than in the nondiabetic population Some limitations, though, are intrinsic to these surveys For example, the NHIS and SIPP represent disability in the noninstitutionalized population More severe cases of disability that require institutionalization are not included in these two surveys see Chapter 28 There also is little assessment of the incidence of disability and no longitudinal followup of the population to examine changes or progression in disability As defined in the frameworks above, disability is a dynamic process Questions also exist about the adequacy of ascertainment of the diabetic population and the ability to distinguish NIDDM from IDDM Because IDDM occurs
infrequently in the population, the 1989 NHIS had only a small sample of IDDM persons n121 total, 101 age 45 years15

SOCIAL SECURITY DISABILITY INSURANCE
The Social Security Administration SSA reports from time to time on the characteristics of people awarded Social Security disability insurance benefits Statistics on the demographic, socioeconomic, and medical characteristics of disabled workers are usually presented in their reports18,19 The definition of disability applied in the Old Age, Survivors, and Disability Insurance OASDI program is quite restrictive Persons must be unable to participate in gainful activity due to a medically determinable physical or mental impairment This impairment must exist for 5 months before the person can qualify for a disabledworker benefit Furthermore, the impairment should be expected to last for at least 12 months or lead to death20 Consequently, this measure of disability is likely to reflect severe cases Disabled individuals with diabetes are reported in SSA statistics when diabetes is the primary cause of disability

COMMUNITY-BASED EPIDEMIOLOGIC STUDIES
Some information on disability is available from surveys of specific populations of
the diabetes community, such as Mexican Americans and persons with IDDM These data provide further examination of the prevalence and risk factors for disability Again, the specific measures of disability differ among the studies

SURVEY OF WORK AND DISABILITY
In 1972 and 1978, the SSA conducted the Survey of Work and Disability, a population-based survey on the characteristics of occupational disability In these surveys, occupational disability was defined as any limitation in the kind and/or amount of work that a person can do as a result of a chronic health condition or impairment21 The categories of work disability included: Severe disability–unable to work regularly or at all

INDUSTRIAL STUDIES
Reports based on industrial populations have described the disability characteristics of persons with diabetes Industrys concern over diabetes-related disability centers around the monetary issues involved with the subsequent loss of production, high rates of absenteeism, and higher insurance premiums In the surveys conducted in this setting, employment records of diabetic individuals were compared with em262

ployment records of those in the work force without diabetes Limitations in
these studies include inadequate identification of diabetic employees, inadequate description of disability in females with diabetes, and lack of matched control groups

Figure 123

Age-Standardized Percent of Persons Age 18 Years Reporting Activity Limitations, US, 1989
60 50

PREVALENCE OF DISABILITY
40

Disability affects large numbers of persons with diabetes in the United States Estimates range from 2050 of the diabetic population Persons with diabetes are two to three times more likely to report disability than their counterparts in the general population The greatest degree of difference appears for the most serious forms of disability Diabetes is often accompanied by another condition leading to disability Estimates of the prevalence of disability associated with diabetes are available from a number of sources There is some discrepancy among studies on the extent of disability in the diabetes population This is due to the diversity of disability measures used Instruments assessing relatively severe forms of disability report lower prevalence rates than those assessing relatively mild forms Figure 122 outlines the scale of disability used in previous studies of diabetes
populations By considering the intensity of the measure, the impact of disability in diabetes can be placed in a better perspective

30 20 10 0

NIDDM

IDDM

Nondiabetic

Source: 1989 National Health Interview Survey

including diabetes, are strongly linked with reported activity limitations in the NHIS2 In 1983-85, diabetes was the 11th most common condition cited as the main cause for activity limitation in the United States, accounting for 27 of all reported cases2 When considered as any contributing cause of activity limitation, diabetes was the sixth most frequent condition cited, explaining 65 of all cases In 1989, the NHIS supplement on diabetes allowed for a more detailed examination of disability related to diabetes About half of all persons with diabetes reported an activity limitation of any type related to an impairment or health problem Figure 123 Activity limitations were two to three times higher for persons with NIDDM and IDDM compared with persons without diabetes Appendix 121 The greatest degree of difference in disability between people with diabetes and the nondiabetic population appeared for the most serious form of activity limitation, being unable to perform
their major activity Table 122 Significant percentages of the diabetic population reported being unable to carry on their major activity NIDDM, 206; IDDM, 139; Appendix 122 A similar proportion of people with diabetes reported being limited in the amount or kind of major activity they could undertake A limitation in major activity was defined as 1 having difficulty in working at a job or business, in housekeeping, or in going to school for persons age 18-69 years, or 2 having difficulty in the independent performance of ADLs for persons age 70 years Figure 124 shows the type of major activity reported
263

NATIONAL HEALTH INTERVIEW SURVEY
The most comprehensive examination of disability indicators is contained in the NHIS Chronic diseases,
Figure 122

The Scale of Disability

Restricted activity days

Limited in amount or kind of major activity

Unable to perform major activity Limited in IADLs Limited in ADLs

Mild
Occupational work disability Limited, but not in major activity Functional capacity limitations Severe work disability Social Security beneficiaries

Severe

ADLs, activities of daily living; IADLs, instrumental activities of daily living

Table 122

Figure
124

Age-Standardized Percent of Persons Age 18 Years, by Type of Activity Limitation Reported, US, 1989
NIDDM
Unable to carry on major activity Limited in the kind or amount of major activity Limited, but not in major activity Not limited 194 190 118 498

Type of Major Activity Reported by 1989 NHIS Participants, by Diabetes Status and Age
Working Keeping house NIDDM IDDM School Other Nondiabetic

IDDM
151 183 89 577

Nondiabetic population
45 61 54 839
18-44 years

45-64 years

Data are age-standardized to the 1989 National Health Interview Survey sample population using three age groups The data representing IDDM subjects are based on small sample sizes Source: 1989 National Health Interview Survey
65 years

by diabetic and nondiabetic subjects in the NHIS A smaller proportion of persons with diabetes, particularly those with NIDDM, reported working at a job or business Perhaps the most important life activity for an adult is being able to work at a job or business In 1990, nearly 42 of persons age 18-69 years with diabetes reported being unable to work or being limited in the kind or amount of work activity they could do22 About 28 of the population reported being unable to
work at all Another measure of disability in the NHIS is the survey of restricted activity days over a 2-week period Restricted activity days are a broader measure of disability because they consider reductions in usual activity related to long-term or short-term conditions14 The discussion above of activity limitations focused on long-term reductions in capacity only In 1989, about one-fifth of the diabetes population reported at least one restricted activity day in the past 2 weeks Table 123, Appendix 123 This proportion was twice that reported by the nondiabetic population

NHIS, National Health Interview Survey Source: 1989 National Health Interview Survey

The distribution of restricted activity days for the diabetic and nondiabetic populations in the 1989 NHIS is shown in Figure 125 While most persons with diabetes did not report any restrictions in their usual activity in the previous 2 weeks, those who did described lengthy cutbacks in activity Thirteen percent of the persons with NIDDM and 11 of those with IDDM reported 6 days of restricted activity in the preceding 14 days This was markedly higher than the 39 of the nondiabetic population indicating a similar degree of
impairment

Figure 125

Percent Distribution of Restricted Activity Days, by Diabetes Status, US, 1989
6 days

3-5 days

1-2 days

None

Table 123

NIDDM

Age-Standardized Percent of Persons Age 18 Years Reporting Any Restricted Activity Days in the Previous 2 Weeks, US, 1989
NIDDM IDDM Nondiabetic
Any restricted activity days Bed days Work-loss days among the employed Other restricted activity days 224 142 112 115 213 147 114 107 103 57 61 52

IDDM

Nondiabetic

40 60 Percent

100

Source: 1989 National Health Interview Survey

264

A Supplement on Aging was included in the 1984 NHIS and was used, in part, to assess disability in basic life activities among the US population age 65 years These basic operations include ADLs and IADLs The ADL scale examines the level of self-sufficiency of the person in basic self-care activities bathing, eating, dressing, transferring from a bed to a chair, using the toilet and mobility23 The IADL scale examines further activities important for living independently cooking, shopping, managing money, using the phone, using transportation, housekeeping24 In 1984, about one-third 335 of the
diabetes population age 65 years was estimated to be dependent in at least one ADL or IADL25 Extrapolated to the 1992 population with diagnosed diabetes26, this represents 11 million persons with diabetes who were dependent Nearly one-quarter 244 were dependent in at least one ADL, and 73 were dependent in 3 ADLs Dependence in this study was defined as having difficulty in performing an activity or being unable to perform an activity due to a health or physical problem, without the help of another person or assistive device25

Information from the 1991-92 panel lists the conditions reported as being the cause of limitations in functional activities, ADLs, or IADLs Diabetes was, again, the seventh most frequently cited condition mentioned as a cause of disability, representing 39 of all responses Figure 126 Diabetes was cited more often as a secondary or tertiary cause of limitation in normal activities than as a primary cause of incapacity

SOCIAL SECURITY DISABILITY INSURANCE
The SSA manages the largest government program for people with disabilities The Social Security Disability Insurance SSDI program is directed toward income support for persons no longer able to work Few
reports have used SSDI data to examine disability issues in persons with diabetes Measuring the impact of diabetes-related disability from this source is difficult in several respects First, applicants for benefits have to demonstrate that their impairment precludes their participation in normal activity and will continue to do so in the long term Thus, only severe cases of disability are identified from this source Second, information is available only on the number of disability claim allowances related to diabetes These represent new judgments for benefits or new judgments that an applicant has established a period of disability No information is available on the total number of diabetes-related beneficiaries in the system Third, the eligibility criteria for benefits have changed considerably
Figure 126

SURVEY OF INCOME AND PROGRAM PARTICIPATION
Two panels of the SIPP, in 1984-85 and 1991-92, have addressed disability issues With an emphasis on gathering data on disability and the use of government programs, the SIPP has not focused to a large extent on the role of chronic conditions in disability The 1984-85 panel, though, did examine the conditions mainly responsible for work
disability and the need for personal assistance Diabetes was the seventh most frequently cited condition listed as being mainly responsible for work disability17 In 1984-85, an estimated 806,000 persons with diabetes had some type of work disability equivalent to 34 of all persons disabled in work activity Of this figure, 482,000 were entirely unable to work and 79,000 were able to work, but not in full-time employment About 245,000 persons with diabetes were estimated to have a disability but were still able to work full-time These findings are in general agreement with the results of other surveys regarding work disability Severe work disability, reflected in the inability to work at all, accounts for the largest proportion of all work-disabled individuals With respect to the need for personal assistance, an estimated 116,000 persons with diabetes needed some help in getting around, while 169,000 persons needed help with housework or meal preparation
265

Diabetes as a Reported Cause of Limitation in Functional Activity, ADL, or IADL, US, 1991-92
7 6 5 4 3 2 1 0 Any Cause Primary Cause Secondary Cause Tertiary Cause

ADL, activities of daily living; IADL, instrumental activities
of daily living Source: 1991-92 Survey of Income and Program Participation, Social Security Administration

over time Fourth, the SSA has only considered the impact of diabetes as a primary cause of disability As demonstrated earlier, diabetes is a significant factor as a second or third condition contributing to disability The latest available data show that 8,250 persons with diabetes were granted disability claims allowances in 198419 This number represents 23 of all allowances given that year

NATIONAL NURSING HOME SURVEY
While the 1984 NHIS Supplement on Aging considered disability in the noninstitutionalized aged population, many older persons with significant disabilities are living in long-term care institutions The 1985 National Nursing Home Survey sampled nursing homes and their residents nationwide Data from this survey and the 1984 Supplement on Aging suggest that 195 of all functionally dependent persons with diabetes dependence in at least one ADL or IADL reside in nursing homes25 In 1985, an estimated 165,000 diabetic persons age 65 years with dependency in at least one ADL or IADL were resident in nursing homes25 Nearly 78 of these persons were dependent in 3 ADLs
Chapter 28 presents more information on disability in institutionalized people with diabetes

SURVEY OF WORK AND DISABILITY
More appropriate measures of disability related to diabetes can be found in the Survey of Work and Disability conducted by the SSA While this specific survey is no longer being administered, the 1972 and 1978 versions indicated that 45-50 of diabetic people were limited in their work activities in one form or another Figure 12727,28 This amount of disability was about three times greater than that in the general population, where 14-17 were work-disabled The largest degree of difference in disability between the diabetic and general populations was found for the most severe form of work disability, being unable to work at all Greater percentages of the diabetic subjects 28-34 were unable to work severe disability compared with the general population 7-8 Higher burdens were also noted for the lesser forms of work disability occupational disability–being able to work, but not full time at the same job; secondary work limitations–able to work the same job, but limited in what the person can do

COMMUNITY-BASED EPIDEMIOLOGIC STUDIES
Measures of disability have
been assessed in separate and distinct epidemiologic surveys of persons with diabetes in US communities Among them, the Pittsburgh Epidemiology of Diabetes Complications EDC Study has examined disability issues since 1986 The EDC study is an ongoing investigation of factors related to diabetes complications in persons with IDDM The study population is based on all childhood-onset diabetes patients seen at the Childrens Hospital in Pittsburgh in 1950-80 who are living in the Pittsburgh, PA region The mean age of the 658 participants at the baseline examination was 28 years The mean duration of IDDM was 20 years29,30 Nearly one person in five in this relatively young cohort reported diabetes-related limitations in the type or amount of work they could do at home, at school, or on the job Table 124 Furthermore, of the 22 reporting limitations at the 4-year followup, oneTable 124

Figure 127

Percent of Persons with Diabetes Age 20-64 Years Reporting Work Disability, by Type of Limitation, US, 1972, 1978
1972 survey Secondary limitation Occupational 1978 survey

Severe

Percent of IDDM Persons Limited in Work, Home, or School Activities Due to Diabetes-Related Problems, Pittsburgh EDC
Study
Sample size no
0 10 20 30 Percent Disabled 40 50

Overall

Percent limited
171 189 216

Baseline survey 1986-88 2-year followup 1988-90 4-year followup 1990-92

625 481 430

Source: 1972 and 1978 Surveys of Work and Disability, Social Security Administration, References 27 and 28

EDC, Epidemiology of Diabetes Complications Source: Pittsburgh Epidemiology of Diabetes Complications Study

266

third had difficulties in at least one ADL, 57 had difficulties in at least one IADL, and 75 reported difficulties in functional capacity ie, walking, standing for long periods, reaching, lifting, grasping, etc The prospective nature of the EDC study highlights the dynamic nature of disability Figure 128 charts the development incidence of diabetes-related limitations from the time of the baseline examination Among those persons reporting no problems in their work activity at baseline, 5 identified a diabetes-related limitation 2 years later and 11 did so at the 4-year follow-up examination Some persons indicated an improvement in their disability status over time: among participants reporting disabilities at baseline, 14 had no trouble at the 2-year followup and 22 had no
diabetes-related limitations at the 4-year examination Another case-control investigation focused on an older cohort mean age 33 years of the CHP IDDM Registry This study surveyed the employment experiences of 158 adults with IDDM and their nondiabetic brothers and sisters31 IDDM subjects were seven times more likely to report being disabled in their work abilities than their age- and sex-matched siblings Table 125 A sizable percentage were unable to work at all 126

Table 125

Percent of Persons Disabled in Work Activity, Childrens Hospital of Pittsburgh IDDM Registry, 1985
IDDM subjects
Any work disability Severe disability Occupational disability Secondary work limitations
Source: Reference 31

Nondiabetic siblings
46 00 06 40

324 126 99 99

lence of impairments increases steadily with age, but disability still affects large numbers of young people with diabetes Disability is more common in women and minority ethnic groups, and it appears to affect persons with NIDDM more frequently than those with IDDM In IDDM, disability increases with longer duration of diabetes

DEMOGRAPHIC FACTORS
The attributes of disability vary enormously from individual to individual Two persons with
the same relative degree of health may respond quite differently when queried about their ability to carry on normal activities One individual may have a supportive environment, while another may not A number of elements are correlated with the evolution of disability in persons with diabetes While it has been difficult to quantify the importance of all the variables that influence disability, there is a great deal of information on the relationship of disability with selected demographic factors age, gender, race, income, education, etc The characteristics of disability in the diabetes community are, in general, similar to those seen in the general population Activity limitations reported in the 1989 NHIS increased with advancing age for persons with NIDDM Figure 129 Data from the 4-year follow-up examination in the EDC study indicate a similar tendency for persons with IDDM Figure 1210 Data from the 1989 NHIS Appendix 121 and the 1972 Survey of Work and Disability Table 126 suggest that the largest degree of difference in reported disability between the diabetic and nondiabetic populations is found at younger ages Increasing rates of disability occur with advancing age in older
diabetic Americans Substantial percentages of the diabetes population age 55 years reported difficulties in at least one ADL in the 1984-85 Supple267

ATTRIBUTES RELATED TO DISABILITY

Disability in persons with diabetes is influenced by a number of factors, the strongest of which is the presence of the late complications of diabetes The prevaFigure 128

Percent of IDDM Persons with No Disabilities at Baseline Who Report Work Limitations at Followup, Pittsburgh EDC Study
12 10 8 6 4 2 0

2-Year Followup

4-Year Followup

EDC, Epidemiology of Diabetes Complications Source: Pittsburgh Epidemiology of Diabetes Complications Study

Figure 129

Figure 1211

Percent of Persons Reporting Activity Limitations, by Age Group, US, 1989
Nondiabetic 18-44 years IDDM NIDDM

Percent of Diabetic Population with Difficulties in ADLs, by Age and Gender, US, 1984
100 80 60
Difficulty in at least one ADL, females Difficulty in at least one ADL, males Difficulty in ADLs, females 3 Difficulty in 3 ADLs, males

45-64 years

40 20

65 years 0 10 20 30 40 50 Percent with Limitations 60 70

0 55-64

65-74 Age Years

75-84

ADLs, activities of daily living; NHIS National Health Interview Survey Source:
Supplement of Aging, 1984 National Health Interview Survey; Reference 32

Source: 1989 National Health Interview Survey

ment on Aging Figure 121132 More than one woman in every two with diabetes indicated a dependency of some type in these self-care activities As a group, women with diabetes have higher rates of disability than men; this pattern is also found in the nondiabetic population Table 127 While disability is more frequent in females, from most indications the gender difference is not significant for the diabetes population Moreover, the excess disability in females may only exist at an older age Activity limitations in the 1989 NHIS were slightly more frequent at age 18-44 years in diabetic men before becoming more
Figure 1210

frequent at age 45 years in diabetic women Figure 1212 The Framingham Heart Study examined the contributory role of diabetes in the development of
Table 126

Percent of Persons Reporting Work Disability, by Age, 1972
Age years
45 45-54 55-64

Diabetic
340 423 574

Nondiabetic
84 190 288

Source: 1972 Survey of Work and Disability, Social Security Administration

Percent of IDDM Subjects Reporting Being Limited in Type or Amount of Work Activity,
by Age, Pittsburgh EDC Study, 1990-92
60 50 40 30 20 10 0 20 25 30 35 Age Years 40 45

Table 127

Percent of Persons Reporting Disability, by Gender
Diabetic Nondiabetic population population - Men Women - Men Women
535 447 231 180 321 155 571 473 326 250 328 90 48 00 45 00 149 136 57 161 150 83

Data source

Disability measure

NHIS, 1989 Activity limitations Survey of Work and Work disability Disability, Severe disability 1972 EDC survey, 1990-92 CHP IDDM Registry, 1985 Work limitations Work disability Severe disability

EDC, Epidemiology of Diabetes Complications; Data are 3-year moving average Source: Pittsburgh Epidemiology of Diabetes Complications Study

NHIS, National Health Interview Survey; EDC, Pittsburgh Epidemiology of Diabetes Complications Study; CHP Childrens Hospital of Pittsburgh , Source: Sources are listed within the table

268

Figure 1212

Figure 1214

Percent of Persons with Diabetes Reporting Activity Limitations, by Age and Gender, US, 1989
No diabetes Diabetic men All diabetes Diabetic women

Prevalence of Activity Limitations in Mexican Americans with Diabetes, by Medical History and OGTT, HHANES, 1982-84
35 30 25 20 15 10 Diabetes No diabetes

70 60 50
40 30 20 10 0 18-44

45-64 Age Years

5 0 Self-Report of Diabetes Diabetes by OGTT

Source: 1989 National Health Interview Survey OGTT, oral glucose tolerance test; HHANES, Hispanic Health and Nutrition Examination Survey

physical disability33 In a cohort of 2,021 persons free of cardiovascular disease, diabetes was associated with measures of physical disability in women, primarily those age 75 years, but not in men Analyses considering racial attributes find higher disability rates in African Americans Figure 1213 shows information from the 1989 NHIS Both black men and black women have a higher prevalence of activity limitations than whites22 Similarly, the prevalence of work disability was higher in African Americans than in whites 552 versus 443 in the 1972 Survey of Work and Disability27

Source: 1982-84 Hispanic Health and Nutrition Examination Survey; Reference 34

Evaluation of other ethnic groups in national surveys is difficult because of small sample sizes However, the 1982-84 Hispanic Health and Nutrition Examination Survey HHANES focused on US Hispanic populations Based on this survey34, activity limitations were nearly two times more common in Mexican Americans
with diabetes than in Mexican Americans without diabetes Figure 1214 Significant associations between disability and education or income were found in the 1989 NHIS Table 128 Activity limitations were highest among perTable 128

Figure 1213

Age-Adjusted Prevalence of Activity Limitations Related to Chronic Conditions in Diabetic Subjects, by Race and Sex, US, 1989

Age-Standardized Percent of Persons Age 18 Years Reporting Activity Limitations, by Education and Income, US, 1989
NIDDM population
Education completed years 9 9-12
13

Black females

Nondiabetic population
227 163 131 306 201 155 118 93

Black males

677 503 407 711 546 460 245 330

White females

Income 10,000 10,000-19,999 20,000-34,999 35,000-49,999
0 10 20 30 40 50 Age-Adjusted Percent 60
50,000

White males

Data are age-standardized to the 1989 National Health Interview Survey sample population using three age groups Source: 1989 National Health Interview Survey

Source: 1989 National Health Interview Survey

269

Table 129

Table 1210

Percent of Persons Reporting Activity Limitations, by Type of Diabetes Treatment, US, 1989
NIDDM, using insulin
635 529 623 681

Prevalence of Disability in IDDM Persons with
Diabetes-Related Complications, Pittsburgh Epidemiology of Diabetes Complications Study, 1990-92
Complication
Retinopathy Nephropathy overt Coronary heart disease Definite peripheral vascular dis ease Definite neuropathy Hypertension All persons with IDDM

Age years
18

NIDDM, NIDDM, using using oral agents diet alone
524 465 476 569 483 261 589 488

IDDM
429 434 398

Prevalence of disability
444 380 542 472 436 436 216

18-44 45-64
65

Source: 1989 National Health Interview Survey

sons with the fewest years of education and the lowest income levels, even after adjusting for age Similar correlations were noted for persons with IDDM in the EDC study While income may be suppressed by disability, the association with lower levels of education indicates a strong tendency for higher rates of disability in lower socioeconomic groups

Source: Pittsburgh Epidemiology of Diabetes Complications Study

Data from the 4-year follow-up examination in the EDC study indicate that the frequency of disability increases with longer duration of diabetes in patients with IDDM Figure 1215 The strongest factor associated with disability appears to be the presence of the late complications of diabetes
Persons with complications are more likely to be impaired in their normal activities than are those without the chronic complications of diabetes In the EDC study, 357 of subjects with complications were limited in the type or amount of work they could perform Only 35 of subjects without complications were so limited There was no single condition or complication that accounted for this finding Each type of complication was significantly associated with disability Table 1210 Higher rates of activity limitations were also observed among respondents with NIDDM and complications in the 1989 NHIS Table 1211
Table 1211

DIABETES-RELATED FACTORS
Table 129 presents the frequency of activity limitations among respondents to the 1989 NHIS diabetes supplement by type of treatment Individuals with NIDDM who were using insulin reported more limitations in normal activities than persons using oral agents or diet alone to control their diabetes Subjects with NIDDM appear to have higher rates of limitation than persons with IDDM, although the sample size of respondents with IDDM was small
Figure 1215

Percent of IDDM Persons Reporting Work Limitations, by Duration of Diabetes, Pittsburgh EDC
Study, 1990-92
60 50 40 30 20 10 0 12 17 22 27 32 Duration of IDDM Years 37

Limitation in Activity of NIDDM Persons with Diabetes-Related Complications, Age 18 Years, US, 1989
Complication
Retinopathy Laser treatment for retinopathy Glaucoma Cataracts Angina or any heart trouble Stroke Kidney disease or proteinuria Amputation Sensory neuropathy Sores on feet that dont heal All persons with NIDDM
Source: 1989 National Health Interview Survey

Limited in activity
663 741 737 649 768 567 735 816 738 723 563

EDC, Epidemiology of Diabetes Complications Data are 3-year moving averages Limitations include those in the type or amount of work that can be performed Source: Pittsburgh Epidemiology of Diabetes Complications Study

270

TRENDS OVER TIME IN DISABILITY

Figure 1216

Trends in Work Limitations Reported by Persons with Diabetes, US, 1983-90

The evidence regarding trends in the prevalence of disability among persons with diabetes is varied Depending on the disability measure applied, reports have indicated increasing, decreasing, or constant prevalence When changes exist, they have been small Interpreting changes in the prevalence of disability related to diabetes over time is
difficult because of the multiple definitions of disability in the literature Moreover, assessment strategies have changed over time, even within similar survey instruments Table 1212 outlines the frequency of activity limitations among persons with diabetes in the NHIS by year28,35 Direct comparisons between the years are complicated because of differences and changes in the assessment of activity limitations Despite variation among the surveys, it appears that activity limitations among persons with diabetes may have remained relatively stable over time Better information, from a comparison perspective, is available on work limitations as assessed in the NHIS Figure 121622 Over the 8-year period of 1983-90, self-reported work limitations changed only slightly, from 439 to 419 A more notable decline was found for white females and all African Americans White males, though, showed an increase in work limitations during 1983-90 Disability allowances in the Social Security program due to diabetes have increased over time Figure 121736 The number of persons with diabetes, however, has also increased Furthermore, there is evidence to suggest that the changes in allowances awarded over
time for all persons have been due, in
Table 1212

1983

Data are 3-year moving averages Source: 1983-90 National Health Interview Surveys; Reference 22

part, to changes in the eligibility criteria for the applicants37

DISABILITY AND EVERYDAY LIFE

Disability affects the lives of persons with diabetes in many different ways A lower proportion of disabled persons with IDDM are in the work force; those who are employed have higher absenteeism rates than workers without disabilities Health care use is increased among disabled people, with the number of physician contacts being twice those of people withFigure 1217

Social Security Disability Allowances, by Year and Diabetes Status
1,000,000 All causes Diabetes

Trends in the Percent of Diabetic Adults Reporting Activity Limitations, US, 1964-89
Age and sex
Age years
20

1964
542 319 464 706 509 566

1979-81
565 361 553 656 550 576

1989
100,000

20-44 45-64
65

Males Females

556 483 547 600 536 571

10,000

The youngest age group in the 1989 data is age 18-44 years Source: Data are from the National Health Interview Surveys: 1964, Reference 35; 1979-81, Reference 28; 1989,
unpublished data from the 1989 Diabetes Supplement

1,000 1957

Source: Reference 36

271

out disabilities Persons developing disability often experience decreases in income levels and greater dependency in basic life activities These factors and others likely contribute to the lower perceptions of health among disabled persons The impact of disability in the diabetes population is wide ranging Thus, studies that only consider the prevalence of disability seriously undervalue the effect that disability has on the lives of those affected Disability influences economic, sociologic, and psychologic parameters, among other areas Significant proportions of disabled persons, for example, are no longer working, particularly those with severe disability21 Income differences, largely related to the loss of earnings with the loss of a job, exist between disabled and nondisabled people5 These findings and others have led to the view that disabled people live in an atmosphere of disadvantage4 The burdens of disability, though, differ by the culture, education, family, and environment in which the person lives Changes in the publics perception of disability, such as the
elimination of bias in job hiring, can increase opportunities for disabled people2 Changes in the physical environment, such as the availability of access ramps, can increase the mobility of disabled people

Table 1213

Self-Reported Employment Status in the Past 2 Weeks by Age and Diabetes Status, US, 1989
Employment status and age years
Currently employed 18-44 45-64 Unemployed 18-44 45-64 Not in the labor force 18-44 45-64

NIDDM
620 470 81 17 299 513

IDDM
791 547 58 47 150 406

Nondiabetic
793 677 38 23 169 300

Source: 1989 National Health Interview Survey

ity will affect the employability of individuals significantly Information from the 1989 NHIS shows that a lower proportion of diabetic than nondiabetic persons are currently employed, even after adjusting for age Figure 1218 Most of this disparity is due to the large number of subjects who are not in the labor force as opposed to being unemployed, particularly for NIDDM Table 1213 The influence of disability on this finding, though, is not clear More direct information is available from the studies of the CHP IDDM Registry, which found that disabled persons with IDDM were more likely to be not working than those who were
not disabled Figure 1219 Data from both the 4-year followup of the EDC study
Figure 1219

UNEMPLOYMENT
If the impact of disability on persons with diabetes is similar to that in the general population, then disabilFigure 1218

Employment Status in the Past 2 Weeks, by Diabetes Status, US, 1989
Currently employed Not in labor force Unemployed

Percent of IDDM Population Not Working, by Disability Status, Childrens Hospital of Pittsburgh IDDM Registry, 1985 and 1990-92
60 50 40 Not disabled Disabled

80 70 60 50 40 30 20

30 20 10

10 0 0 NIDDM IDDM Nondiabetic EDC Study 1950-65 Cohort

Data are age-standardized for persons age 18-64 years Source: 1989 National Health Interview Survey

EDC, Pittsburgh Epidemiology of Diabetes Complications Source: Pittsburgh Epidemiology of Diabetes Complications Study; Reference 31

272

and a 1985 study of the IDDM cohort diagnosed in 1950-6531 indicate that about half of the disabled respondents were not working This figure was two to three times greater than that observed among subjects without disability

IDDM Registry, however, no difference in absenteeism was found between working IDDM persons and their working nondiabetic siblings31 While the
debate continues regarding the importance of absenteeism in persons with diabetes, one solid conclusion arising from these studies is that significant rates of absenteeism are limited to a small subset of the diabetic population Most diabetic employees appear to have normal work attendance records In addition, there is the suggestion that many of the individuals with high rates of absenteeism may be disabled Data from the 1979-81 NHIS indicate a higher number of work-loss days among diabetic workers with activity limitations than among those without activity limitations 175 days per year versus 99 days per year28 Similarly, a higher rate of absenteeism was observed for working IDDM subjects with disability than for those without disabilities 138 days per year versus 3 days per year The distribution of the number of days absent from work for employed IDDM persons in the CHP IDDM Registry is shown in Figure 1220 Excess absenteeism for disabled persons was noted for the category of 10 days absent per year but not for the categories with fewer days of absence These data may reflect that disabled people either tend to be absent more frequently or tend to be absent for longer periods
when they are away from work

ABSENTEEISM
For some time now, there has been concern among employers that diabetic employees may have high rates of absenteeism In the 1950s, concern about diabetes and its implications for loss of productivity and higher insurance premiums led to an examination of disability in the working diabetic population at several industrial sites The general results of these studies of absenteeism are presented in Table 121438-44 The findings of the surveys were variable and showed favorable, normal, or unfavorable experiences for the diabetic groups Most found higher rates of absenteeism for the diabetic employees There are several methodological shortcomings in these surveys, however, that limit extrapolation of the findings to the general diabetic population These include the means of identifying employees with diabetes and the inadequate matching with controls Absenteeism associated with diabetes has also been assessed in the 1989 NHIS Absenteeism, measured as the number of work-loss days in the previous 2 weeks, was notably higher among both NIDDM and IDDM respondents, compared with the experience of the nondiabetic population Appendix 123 In the
CHP
Table 1214

Figure 1220

Frequency Distribution of Absenteeism per Year for Currently Employed IDDM Subjects, by Disability Status, 1950-64 Cohort, CHP IDDM Registry

Industry-Based Studies of Absenteeism in Diabetes
Absence Absence rate of rate of No of diabetic nondiabetic diabetic employees employees employees days/year days/year
10 40 90 408 622 273 108 24 316 98 108 130 105 63 49
20 50 40 30 Not disabled Disabled

Ref

Study, year

38 An insurance company, 1950 39 Third Ave Transit System, 1951 40 Oil refinery, 1956 41 Dupont Co, 1956 42 Dupont Co, 1963 43 Ford Motor Co, 1959-64 44 Hanford Operations Co, 1974

196 88 56 69 35 75
CHP Childrens Hospital of Pittsburgh , Source: Pittsburgh Epidemiology of Diabetes Complications Study

10 0

1-5 6-10 Days Absent

Source: References are listed within the table

273

Table 1215

Table 1216

Health Care Use by Disability Status, Age 18 Years, US, 1989
Diabetic Nondiabetic population population Not Not Limited limited Limited limited
Physician visits Physician contact in the past year Hospitalizations Hospitalized in the past year Average length of stay per discharge days

Health Care Use Rates for IDDM Persons, by
Disability Status
Type of health service
Average number of hospital admissions per year Average number of outpatient physician visits per year Average number of emergency department visits per year

Limited
095 1034 114

Not limited
042 463 063

957

932

890

720

324

132

220

Source: Pittsburgh Epidemiology of Diabetes Complications Study

142

113

HEALTH CARE USE
Disability has concomitant effects on the use of medical services In diabetes, a number of medical problems give rise to disability Hence, there is a strong association between disability and the use of medical care Disabled subjects with diabetes, in general, use health care services more frequently than nondisabled persons with diabetes Disabled subjects with diabetes also appear to use medical care more often than disabled persons who do not have diabetes Table 1215 and Figure 1221 describe this pattern for hospital and outpatient physician care Figure 1222 and Table 1216 outline the medical care/disability association for IDDM subjects in the EDC study Persons limited in the kind or amount of work they could perform were more likely to use hospital, emergency department, and outpatient physician
services Their total number of health care conFigure 1222

Source: 1989 National Health Interview Survey

DISCRIMINATION
With a higher degree of unemployment and absenteeism, there is concern that persons with diabetes may face discrimination in the workplace Indeed, some reports suggest that this has taken place in the past31,45 The extent to which disabled persons with diabetes are discriminated against is not known The 1990 Americans with Disabilities Act, however, may increase employment possibilities for disabled persons with diabetes This legislation seeks to expand the opportunities of disabled persons by providing standards in employee hiring and by allowing for work rule and work environment changes to meet the needs of those with disabilities
Figure 1221

Average Number of Physician Visits for Respondents with at Least One Visit, by Diabetes Status, Disability Status, and Age, US, 1989
25 20 15 10 5 0 Diabetic, limited in activity Diabetic, not limited Nondiabetic, limited Nondiabetic, not limited

Percent of IDDM Subjects Using Health Care, by Type of Health Care Service and Disability Status, Pittsburgh EDC Study, 1990-92
100 Not disabled
Disabled

18-44

45-64 Age Years

Hospital

Emergency Room

Physician

EDC, Epidemiology of Diabetes Complications Source: 1989 National Health Interview Survey Source: Pittsburgh Epidemiology of Diabetes Complications Study

274

tacts averaged twice the figure reported by those not limited

ACCESS TO HEALTH CARE
Shortcomings in the present health care system, such as insurance exclusions brought about through preexisting illness clauses, raise some concern about the ability of disabled persons to obtain health care when they need it Overall, there is very little information available specific to this issue Data on IDDM persons in the EDC study indicate that persons with activity limitations are more likely to report difficulties in obtaining medical care than those not disabled 196 versus 86, p0003 While most subjects reporting disability had health insurance coverage 903, they were more likely to be covered by individual plans than by group plans 25 versus 116, p0003 As a result, they more often reported paying higher rates for insurance coverage than did those not disabled 87 versus 28 These data suggest that economic factors could influence some of the
health care decisions of disabled persons

cause and effect in this relationship The loss of income arising from severe work-limiting disabilities is a pervasive economic burden faced by disabled people Figure 1223 describes the change in income levels observed in the EDC study for IDDM subjects who did and did not develop disability in the 4 years since their baseline examination Persons who were free of disability at baseline and reported a disability at 4year followup were more likely to report a decrease in household income levels over time than were participants who remained free of disabilities 235 versus 146 Equally important, those developing disability were also less likely to experience an increase in income level 294 versus 496

RESTRICTIONS IN NORMAL ACTIVITIES
Limitations in the normal activities of living, such as the abilities to care for oneself, to get around, and to maintain a household, have been viewed in the literature from two different perspectives Most often, these types of limitations in ADLs or IADLs have been observed as evidence of disability Other reports, though, have examined these types of limitations as resultant outcomes of disability As
demonstrated earlier, extended impairments in basic life activities signal a greater degree of dependency for the affected individual and an increased likelihood for institutionalization The 1989 NHIS examined the frequency in which certain respondents those age 18-59 years with activity limitations and all persons age 60-69 years required assistance in personal care ADLs or other routine care needs IADLs Overall, persons with diabetes either NIDDM or IDDM were more likely to report dependency in these activities than those without diabetes, even after adjusting for age Figure 1224 Individuals with IDDM appeared to have a markedly higher frequency of dependency in personal care needs This degree of dependency in ADLs occurred in the young as well as in the middle-aged Table 1217 Among IDDM subjects surveyed in the EDC study, about one-third of those reporting disabilities limitations in the kind or amount of work they could perform had difficulty in performing at least one ADL Table 1218 Fifty-seven percent reported at least one restriction in the IADLs Seventy-five percent reported some type of functional capacity limitation The impairments most frequently cited by the respondents
were difficulty in lifting heavy items; difficulty in doing heavy housework such as scrubbing floors and windows; difficulty in standing for long periods
275

ECONOMIC DIFFICULTIES
Income differences have been widely noted between disabled and nondisabled persons4,5 While disability rates are higher for individuals in lower socioeconomic categories, it is often difficult to distinguish
Figure 1223

Percent of IDDM Subjects with a Change in Income Level in 4 Years, by Disability Status, Pittsburgh EDC Study
Not disabled Developed disability Decreased income

Increased income

No change

20 30 Percent

EDC, Epidemiology of Diabetes Complications Change in income level is calculated from the baseline examination to the 4-year follow-up examination Source: Pittsburgh Epidemiology of Diabetes Complications Study

Figure 1224

Age-Standardized Percent of Persons Reporting Difficulties in ADLs and IADLs, by Diabetes Status, US, 1989
16 14 12 10 8 6 4 2 0 Personal Care Routine Activities NIDDM IDDM Nondiabetic

adequate measures to assess the importance this plays in the lives of disabled persons and the manner in which they cope with it, one common practice in the health
care literature is to address the quality of life of the affected individuals Quality-of-life measures often survey a much larger range of experiences than found in a typical disability evaluation Assessments of health-related quality of life, for example, examine the impact of disease, disability, and health care treatments over a spectrum of five broad concepts: opportunity, health perceptions, functional states, impairments, and duration of life46 These concepts touch on diverse disciplines, ranging from physical functioning to social functioning to mental health to disadvantage to disease symptomatology A variety of health-related quality-of-life instruments exist46 While many surveys try to focus on all aspects of health-related quality of life by using a health index or health profile, a number of studies consider only one area, such as physical functioning or health perception Both types of measures have been applied to evaluate quality of life in persons with diabetes
Table 1218

ADL, activities of daily living; IADL, instrumental activities of daily living Source: 1989 National Health Interview Survey

of time; and difficulty in stooping, crouching, or kneeling

QUALITY OF
LIFE
Disabled persons face a number of practical obstacles in everyday life4 Physical, social, emotional, and other barriers exist and affect disabled people to varying degrees Some, such as occupational problems, are easy to identify from a research perspective Others, including the day-to-day burdens that disabled people encounter, are more difficult to quantify It is likely that many persons with disabilities live with uncertainty about what lies ahead While there are few
Table 1217

Percent of Disabled IDDM Subjects Reporting Restrictions in Normal Activities by Type of Activity, Pittsburgh EDC Study, 1990-92
Type of activity
Activities of daily living Bathing and showering Dressing Eating Getting in/out of chairs/bed Getting outside Using the toilet Instrumental activities of daily living Preparing meals Shopping for personal items Managing money Using the telephone Doing heavy housework Doing light housework Functional capacity limitations Walking for one-quarter mile Walking up to 10 steps Standing for 2 hours Sitting for 2 hours Stooping, crouching, kneeling Reaching over your head Reaching out to shake a hand Grasping or handling objects Lifting or carrying 25 lbs Lifting
or carrying 10 lbs
EDC, Epidemiology of Diabetes Complications

Percent
333 75 118 108 140 129 43 570 172 187 144 65 495 120 753 366 237 430 228 424 250 76 308 500 258

Percent of Persons Reporting Restrictions in Normal Activities, by Type of Activity and Age, US, 1989
Activity and age years
Personal care needs eg, bathing, eating, dressing 18-44 45-69 Other routine needs eg, household chores, shopping, etc 18-44 45-69

NIDDM IDDM

Nondiabetic population

39 50

84 103

18 25

141 141

125 157

71 63

Source: 1989 National Health Interview Survey

Source: Pittsburgh Epidemiology of Diabetes Complications Study

276

HEALTH PERCEPTIONS
A common indicator of health perception is the selfrating of health Subjects typically are asked to rate their current health status as excellent, very good, good, fair, or poor Relatively few persons with NIDDM or IDDM in the 1989 NHIS rated their health as excellent 58 and 122, respectivelyAppendix 124 A large proportion of respondents with NIDDM, in fact, rated their health as either fair 302 or poor 199 These patterns contrasted sharply with the responses of the nondiabetic population even after adjusting for age Figure 1225 A similar experience
was reported for older adults in Beaver Dam, WI47 Both insulin-using and noninsulinusing diabetic persons had lower health scores than the general population without diabetes Higher frequencies of morbidity and disability in the diabetic population are likely to account for some proportion of the lower health ratings of diabetic subjects A survey of 170 adults with IDDM, for example, illustrated that patients with nephropathy had lower health perceptions and increased worry over their health than patients with no diabetic complications48 Moreover, diabetic individuals with disability report markedly lower levels of health than persons without disabilities Table 1219 shows the distribution of diabetic subjects in the 1989 NHIS by self-reported health status and the presence of disability Figure 1226 shows the distribution of IDDM subjects in the EDC study by their health ratings and disability status About half of the IDDM individuals with disFigure 1225

Table 1219

Percent of Adults by Self-Reported Health Status and Disability Status, Age 18 Years, US, 1989
Diabetes population
Excellent Very good Good Fair Poor 20 63 248 352 317 114 243 388 220 36

General population
94 178 315
265 149 400 319 230 47 05

Health status Limited Not limited Limited Not limited

Source: 1989 National Health Interview Survey

ability rated their health as either fair or poor In contrast, only 11 of the respondents without disabilities indicated the same

HEALTH PROFILES
A more comprehensive assessment of quality of life may be obtained from health profiles The health profiles most frequently used include the Sickness Impact Profile SIP and the Short Form Health Survey SF36 Both examine an extensive number of quality-oflife domains, involving physical and psychosocial functioning, impairment and health perceptions46 The Diabetes Quality of Life DQOL measure, developed in the Diabetes Control and Complications Trial DCCT, is another instrument more specific to the issues facing persons with diabetes It includes four scales: satisfaction, impact, diabetes-related worries, and social/vocational worries
Figure 1226

Self-Reported Health Status for Diabetic and Nondiabetic Persons, US, 1989

Self-Reported Health Status by Disability Status for IDDM Subjects, Pittsburgh EDC Study, 1990-92
Poor 50
Non-disabled Disabled

Excellent

Very
good

Good

Fair

NIDDM

IDDM

Nondiabetic

Excellent Very Good

Good

Fair

Poor

Data are age-standardized using three age groups and the overall NHIS cohort as a standard population Source: 1989 National Health Interview Survey

EDC, Epidemiology of Diabetes Complications Source: Pittsburgh Epidemiology of Diabetes Complications Study

277

Overall, it appears that persons with diabetes have poorer health status and quality of life, as measured by health profiles, than do persons without diabetes Among the 9,385 adults participating in the Medical Outcomes Study, the 844 subjects with diabetes scored markedly lower on four of the six health measures in the SF-20 health perceptions, physical, role, and social functioning compared with patients with no chronic conditions Figure 122749 There was no difference in the mental health and bodily pain domains The majority of the diabetic subjects in the Medical Outcomes Study had NIDDM Similarly, 393 persons with NIDDM in the San Antonio Heart Study population reported higher rates of functional impairment than did 486 nondiabetic controls 366 versus 16750 Functional impairment was defined in this
report as a SIP score of 20 or higher The assessment of quality of life among disabled persons with diabetes, as determined from health profiles, has not yet been examined Indications from two studies, however, suggest that individuals with diabetic complications have diminished levels of quality of life In the San Antonio, TX study, diabetic persons with vascular complications had a higher prevalence of functional impairment 459 than individuals without complications 31850 In a study of 240 persons with IDDM and NIDDM attending an outpatient clinic, the SF-36 and the DQOL measures were administered In both measures, the quality of life of subjects with severe diabetes complications was lower than that for subjects with no complications51

Figure 1227

Average Health Scores in the SF-20 for Diabetic Patients and Patients with No Chronic Conditions by Type of Health Measure, 1989
100 80 60 40 20 0
No chronic conditions Diabetes

Physical Role Social Functioning

Mental Health Health Perceptions

Bodily Pain

Source: Medical Outcomes Study; Reference 49

HEALTH PREFERENCES
Another type of assessment of health-related quality of life incorporates the explicit values or preferences of
surveyed individuals for various types of health By considering the relative desirability that individuals place on health, these types of assessments allow one to combine the different domains of health-related quality of life into a single index46 The measurement of health state preferences also permits the integration of quality of life with quantity of life in health care evaluations46 The health states of diabetic subjects in the 1982-84 followup of the First National Health and Nutrition Examination Survey were examined52 and their responses to the health states considered in the Health

Utility Index HUI53 were mapped In general, diabetic subjects had lower levels of health-related quality of life as estimated by the preference-based measures of the HUI than did persons without diabetes The age-adjusted HUI score for diabetic subjects treated and not treated with insulin was 061 and 070, respectively, compared with a score of 079 for nondiabetic persons The HUI scales health from a score of 0 assigned to death to a score of 1 assigned to complete health The association between diabetes complications and HUI scores was mixed Diabetic subjects with cataracts, stroke, or
hypertension had markedly lower HUI scores poorer quality of life than did persons without these complications No significant differences were noted, however, among persons with glaucoma, or chronic heart disease A similar overall finding using a different survey was reported from the Beaver Dam, WI Health Outcomes Study47 Age-adjusted time-trade-off scores were comparatively lower for diabetic subjects treated and not treated with insulin than for persons without diabetes

Dr Thomas J Songer is Assistant Professor, Department of Epidemiology, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, PA

278

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2:448-53, 1953 40 Weaver NK, Perret JT: The diabetic in industry The Medical Bulletin, Standard Oil Co and Affiliated Companies 18:30416, 1958 41 Pell S, DAlonzo CA: Sickness and injury experience of employed diabetics Diabetes 9:303-10, 1960 42 Pell S, DAlonzo CA: Sickness absenteeism in employed diabetics Amer J Public Health 57:253-60, 1967 43 Nasr ANM, Block DL, Magnuson HJ: Absenteeism experience in a group of employed diabetics J Occup Med 8:621-25, 1966 44 Moore RH, Buschbom RL: Work absenteeism in diabetics Diabetes 23:957-61, 1974 45 Weinstock M, Haft JI: The effect of illness on
employment opportunities Arch Environ Health 29:79-83, 1974 46 Patrick DL, Erickson P: Health Status and Health Policy: Quality of Life in Health Care Evaluation and Resource Allocation Oxford University Press, New York, NY, 1993 47 Fryback DG, Dasbach EJ, Klein R, Klein BEK, Dorn N, Peterson K, Martin PA: The Beaver Dam Health Outcomes Study: Initial catalog of health-state quality factors Med Decis Making 13:89-102, 1993

48 Parkerson Jr GR, Connis RT, Broadhead WE, Patrick DL, Taylor TR, Tse CKJ: Disease-specific versus generic measurement of health-related quality of life in insulin-dependent diabetic patients Medical Care 31:629-39, 1993 49 Stewart AL, Greenfield S, Hays RD, Wells K, Rogers WH, Berry SD, McGlynn EA, Ware JE Jr: Functional status and well-being of patients with chronic conditions; results from the Medical Outcomes Study JAMA 262:907-13, 1989 50 Mitchell BD, Stern MP Haffner SM, Hazuda HP Patterson JK: , , Functional impairment in Mexican Americans and non-Hispanic whites with diabetes J Clin Epidemiology 43:319-27, 1990 51 Jacobson AM, De Groot M, Samson JA: The evaluation of two measures of quality of life in patients with Type I and Type II diabetes Diabetes
Care 17:267-74, 1994 52 Barofsky I, Erickson P Eberhardt M: Assessing health-related , quality of life in persons with diabetes mellitus in press 53 Torrance GW, Boyle MH, Horwood SP: Application of multiattribute utility theory to measure social preferences for health states Operations Research 30:1043-69, 1982

280

APPENDICES

Appendix 121

Appendix 123

Percent of Persons Reporting an Activity Limitation by Sex, Age, and Diabetes Status, US,1989
Sex and age
All adults Males Females Age years 18-44 45-64
65

Percent of Adults Reporting Restricted Activity Days in the Past 2 Weeks by Type of Restriction, Sex, Age, and Diabetes Status, US, 1989
Sex and age
Any type of restriction Males Females Age years 18-44 45-64
65

NIDDM
563 538 580 450 550 600

IDDM
429 498 351 434 398

Nondiabetic
156 149 161 85 213 335

NIDDM
217 182 243 231 209 221 123 99 141 160 114 123 108 89 130 118 105 102 122 97 140 111 108 137

IDDM Nondiabetic
200 199 201 187 270 129 151 101 111 223 123 126 116 127 88 110 94 129 113 95 102 89 114 98 102 121 57 46 66 58 57 54 65 58 73 69 55 43 52 41 61 44 55 77

Source: 1989 National Health Interview Survey

Appendix 122

Percent of Adults Reporting Activity
Limitations, by Type of Activity, Sex, Age, and Diabetes Status, US, 1989
NIDDM
Unable to carry on major activity Males Females Age years 18-44 45-64
65

Bed days Males Females Age years 18-44 45-64
65

IDDM
139 112 169 128 200

Nondiabetic
44 52 36 21 76 78 59 51 67 36 79 118 52 46 58 27 58 141

206 243 179 172 257 168 193 159 218 193 168 216 164 137 182 85 125 216

Work loss days Males Females Age years 18-44 45-64
65

Limited in kind or amount of major activity Males Females Age years 18-44 45-64
65

Other restricted activity days Males Females Age years 18-44 45-64
65

201 289 102 218 107

Data on work-loss days pertain to currently employed persons only Source: 1989 National Health Interview Survey

Limited, but not in major activity Males Females Age years 18-44 45-64
65

89 97 80 89 91

Source: 1989 National Health Interview Survey

281

Appendix 124

Percent Distribution of Adults, by Self-Reported Health Status, Sex, Age, and Diabetes Status, US, 1989
Sex and age
All adults Excellent Very good Good Fair Poor Males Excellent Very good Good Fair Poor Females Excellent Very good Good Fair Poor Age 18-44 years Excellent Very good Good Fair Poor Age 45-64 years Excellent Very
good Good Fair Poor Age 65 years Excellent Very good Good Fair Poor

NIDDM
58 136 305 302 199 78 155 295 278 194 44 123 313 318 202 117 176 271 301 134 52 130 319 290 209 50 132 301 312 205

IDDM
122 259 408 143 69 146 312 372 109 61 94 198 448 181 79 118 296 382 160 44 139 47 556 48 211

Nondiabetic
352 297 243 81 27 389 297 217 68 28 318 296 266 93 26 422 321 201 47 10 296 279 280 106 40 175 231 345 175 74

Source: 1989 National Health Interview Survey

282

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