Disability-free life expectancy of elderly people in a ...

Age and Ageing 2003; 32: 401–405

Age and Ageing Vol. 32 No. 4 # 2003, British Geriatrics Society. All rights reserved.

Disability-free life expectancy of elderly people in a population undergoing demographic and epidemiologic transition S UTTHICHAI J ITAPUNKUL1 , C HAIYOS K UNANUSONT2 , W IPUT P HOOLCHAROEN 2 , P AIBUL S URIYAWONGPAISAL3 , S HAH E BRAHIM4 1

Department of Medicine, Faculty of Medicine, Chulalongkorn University, Bangkok, 10330, Thailand AIDS Division, Department of Communicable Disease Control, Ministry of Public Health, Thailand 3 Thailand Health Research Institute, National Health Foundation, Thailand 4 Department of Social Medicine, University of Bristol, Canynge Hall, Whiteladies Road, Bristol BS8 2PR, UK 2

Address correspondence to: S. Ebrahim. Fax: (q44) 117 928 7325. Email: [email protected]

Background: the major purpose of health and social policy in old age is to increase quality of life of elderly people. In many demographically developing countries, life expectancy is increasing very rapidly, but little information is available on survival free of disability. Objectives: to determine prevalence and severity of disability among the elderly population and to compare disability-free life expectancy and self-care life expectancy among different age groups and between men and women. Design: a cross-sectional multi-stage random sample survey and routine life tables for Thailand. Setting: national population of Thailand. Subjects: 4,048 elderly subjects aged 60q years. Results: prevalence rates (95% CI) of long-term disability and dependency in self-care activities of daily living were 19% (95% CI 17.8, 20.2) and 6.9% (6.1, 7.7) respectively. Rates of disabilities increased with age and women were more disabled than men. The life expectancy and disability-free life expectancy at age 60 for men were 20.3 years and 16.4 years, and for women were 23.9 years and 18.2 years respectively. Self-care life expectancies at age 60, calculated from the prevalence of needing help with basic self-care activities, were 18.6 years and 21.3 years for men and women respectively. Women spent proportionately more of their longer life expectancy in a disabled state than men. Men and women can, respectively, expect that 19% and 24% of their life expectancy at age 60 will be spent in a disabled state, but may expect only about 10% of their life expectancy to be spent unable to manage basic self-care activities of daily living. Conclusion: long-term disability is common in old age, affecting a quarter of people over 60 years. However, selfcare problems are much less common and suggest that the social and health care consequences of demographic transitions are over-estimated by use of simple questions about limiting long-standing disability. Self-care life expectancy provides a useful monitoring tool for censuses and national disability surveys. Keywords: disability, disability-free life expectancy, activities of daily living

Introduction The past 20 years have seen increases in the occurrence of chronic and degenerative diseases in many developing countries as the demographic switch from high birth and death rates to much lower rates, results in ageing of

populations [1, 2]. Many disabling diseases and impairments such as dementia, heart failure, stroke, hearing and visual impairments, and effects of trauma remain incurable. As population ageing is inevitably associated with increased numbers of people at risk of these problems, there is concern that over-stretched health and

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Abstract

S. Jitapunkul et al. social services will be unable to cope [3]. The main objective of health and social policy on ageing in most countries is to improve or maintain the quality of life of older people, ensuring that they survive free of disability for as long as possible. However, the methods of measuring disability-free life expectancy (DFLE), while long-established [4], are not widely used, particularly in the rapidly ageing populations of countries undergoing demographic transition. National disability surveys are relatively easy to perform and provide essential data on the prevalence of disability at different ages that can be used to calculate disability-free life expectancy (DFLE). In this paper, we compare DFLE calculated using different standardised questions on disability in the Thai 1997 National Health Examination Survey II and abridged life tables for Thailand.

Materials and methods

Long-term disability

Two questions were used to identify those participants with long-term disability assessed in terms of activity limitation: ‘Have you had any condition or health problem for 6 months or longer?’ and ‘Does it prevent or limit you in the kind or amount of activity you can do?’ A positive response to both of these questions was defined as long-term disability. For those reporting long-term disability, severity was assessed by the degree of locomotor disability: mild – not confined to home; moderate – confined to home; severe – unable to move about a room and/or to transfer from bed to chair. Self-care disability

Data on basic activities of daily living using the modified Barthel ADL Index [5, 6] were collected. Need for assistance (defined as inability to perform without assistance or requiring help from another person) with self-care

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Results The mean age (SD) of the 4,048 participants was 69.7 (7.3) years. Fifty-seven per cent were women. Prevalence rates of long-term disability and self-care disability were 19% (95% CI 17.8, 20.2) and 6.9% (6.1, 7.7) respectively. The rate of disabilities increased with age. Women suffered more from disability than men (Table 1). Severity of long-term disability and self-care disability is shown in Table 2. While the prevalence of long-term disability was considerably higher than self-care disability, similar proportions of people were classified as severely affected using either criterion of disability. The agreement between the long-term and self-care disability measures was poor (kappa=0.18) but agreement between levels of severity among those with disability showed better agreement (weighted kappa=0.36).


A multi-stage random sampling cross-sectional survey (National Health Examination Survey II) was performed in 1997 by the Ministry of Public Health of Thailand. The sampling frame used was derived from the decennial census of 1995–1996 which defined four main geographic regions of Thailand from which eight provinces within each region were randomly selected. From these provinces, between 61 and 71 villages/communities were randomly selected, and within each village/community 15 people aged 60q years were randomly selected to take part in the survey. Bangkok was sampled as if it was a region and a similar stratified random sampling system used. A target of 1,000 participants in each region was set and interviews were held in participants’ homes with repeat visits made as necessary by Ministry of Public Health personnel. A response rate of 80.8% was achieved. A structured interview schedule was used.

activities of daily living (feeding, grooming, transferring, toileting, dressing and bathing) was assessed by reports of participants, and where appropriate, their carers. Severity was assessed by the number of dependent activities of daily living (ADLs): mild – dependence on 1–2 ADLs; moderate – dependent on 3–4 ADLs; severe – dependent on 5 or more ADLs. Prevalence of long-term disability and self-care disability were calculated by age and sex and used for estimating the long-term disability-free life expectancy (LDFLE) and self-care life expectancy (SCLE) respectively [7, 8]. Health expectancies were calculated using the method developed by Sullivan [4]. The abridged life table for the Thai population, by sex, as constructed for 1996, in particular the number of person-years lived in the various age intervals was used (‘nLx’ column). The abridged life table was obtained from the National Statistical Office [9]. For this study, only life expectancies for the agegroup 60 years and over were relevant. The years lived in the various age intervals were divided into years spent without disability and with disability. The years with disability are the product of the prevalence of disability (long-term disability and self-care disability) and the years lived in various age groups. In this way a new series of nLx-values was generated, which was used to construct new life tables showing number of years that people can be expected to live with disability. The number of years without disability is obtained by subtracting the number of years with disability from the total life expectancy. The ratios between health expectancy and life expectancy were calculated and presented as percentages. The coefficients of agreement (Kappa coefficients) between presence of long-term disability and presence of self-care disability, and between levels of severity of longterm disability (no, mild, moderate, severe–very severe) and levels of severity of self-care disability (no, mild, moderate, severe) were calculated [10, 11].

Disability-free life expectancy of elderly people Table 1. Prevalence rates of total disability, long-term disability and dependency on self-care activities of daily living (one or more activities of feeding, grooming, transferring, toileting, dressing and bathing) by demographic and social factors. Thailand, 1996–1997 Long-term disability

Total disability

Dependency in any self-care ADLs

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

14.8 21.6 32.9

21.3 27.2 37.4

4.2 7.3 19.1

17.4 20.2

22.0 27.2

5.7 7.9

15.1 22.5 23.2

20.4 30.3 39.2

4.6 6.9 11.1

20.5 17.6

25 25

7.7 6.2

25.5 20.8 19.6 17.7

34.6 28.9 27 22.2

9.6 7.4 5.8 7.1

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

(81.0) (14.2) (3.1) (0.7) (0.9)

No Mild Moderate Severe

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

LE

LE

LDFLE

SCLE

LDFLE

SCLE

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

60–64 65–69 70–74 75–79 80q

20.29 17.14 14.18 11.87 10.90

16.39 13.53 10.93 8.96 7.89

18.65 15.51 12.63 10.37 8.96

23.89 20.20 16.89 14.60 13.60

18.18 14.77 11.84 9.84 8.71

21.30 17.59 14.34 12.03 10.76

5.7 (24% of life expectancy) years of disabled life expectancy. By contrast, men aged 60 years had a life expectancy of 20.3 years and a LDFLE of 16.4 years, resulting in 3.9 (19% of life expectancy) years spent in a disabled state. By contrast, the sex difference in self-care life expectancy is smaller than the LDLFE with very similar proportions of life expectancy spent unable to self-care (See Table 4).

Long-term disability Number (%) Self-care disability Number (%) 3,279 576 126 29 38

Female

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

LDFLE = long-term disability-free life expectancy; SCLE = self-care life expectancy; LE = life expectancy.

Table 2. Severity of long-term and self-care disability (one or more activities of feeding, grooming, transferring, toileting, dressing and bathing). Thailand, 1996– 1997 No Mild Moderate Severe Very severe

Male

3,769 174 49 57

(93.1) (4.3) (1.2) (1.4)

Life expectancy (LE), long-term disability-free life expectancy (LDFLE) and self-care life expectancy by age and sex are shown in Table 3. Although women have a longer life expectancy than men, they spend more years in disabled states. At the age of 60–64, women had a life expectancy of 23.9 years, and on average could expect to spend 18.2 years free from long-term disability, leaving

Discussion The estimates of disability-free life expectancy derived from this representative national survey are within the same range as those derived for other countries [8, 12– 14]. Although overall levels of reported long-standing disability were high, until disability results in difficulties with self-care it is of relatively little consequence in terms of burdens on the family, society and health care systems. An important limitation of our survey is the lack of information about mental health problems and impairments of hearing and vision which may not be severe enough to limit self-care but may contribute to burdens on families and the health care system. Inevitably those older people who are unable to care for themselves will require some form of care in both demographically developed and developing countries, which may result in a direct cost to public health and social services, or an indirect cost through reduced productivity among family and unpaid carers [15, 16].

Table 4. Ratios of health expectancy versus life expectancy by age and sex. Thailand 1996–1997 Male

Female

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

LDFLE/LE (%)

LDFLE/LE (%)

SCLE/LE (%)

SCLE/LE (%)

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

60–64 65–69 70–74 75–79 80q

80.78 78.94 77.08 75.48 72.38

91.92 90.49 89.07 87.36 82.20

76.10 73.12 70.10 67.40 64.04

89.16 87.08 84.90 82.40 79.12

LDFLE = long-term disability-free life expectancy; SCLE = self-care life expectancy; LE = life expectancy.

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Age groups 60–69 70–79 80q Sex Male Female Reading ability Fluent Not-fluent Cannot Area of living Urban Rural Financial problems Usually Sometimes Occasional Never – rare

Table 3. Life expectancy and long-term disability-free life expectancy and self-care life expectancy by age and sex. Thailand, 1996–1997

S. Jitapunkul et al.

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consider that there is a clear role for international health and policy agencies to aid collaboration in designing disability questions so that broad comparability over time and between places is possible.

Key points . One in four elderly people reported disability, one

in 20 were homebound and one in a 100 were bed-bound. . Thai men spent more of their life expectancy free of disability than Thai women, but similar proportions of time free of self-care disability. . With increasing age, the proportion of remaining life expectancy spent in disabled states increases in both men and women. . Self-care life expectancy is a useful indicator for monitoring the achievement of national health and social policy objectives.

Acknowledgements This project was carried out under collaboration of the Ministry of Public Health of Thailand and the National Health Foundation. The authors wish to thank the Ministry of Public Health, the National Health Foundation and the National Statistical Office for their generous support of this research. We also thank all members of the Administrative Committee and the Technical Committee of this project.

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The calculation of DFLE using prevalence data makes no allowance for people who recover, which is relatively common [17, 18]. The true levels of dependency and likely burdens associated with an ageing population are therefore over-estimated using the simple methods used here. Ideally, longitudinal data should be used as this permits transitional probabilities of moving between disabled states to be included in calculations of DFLE. However, establishing large scale, nationally representative longitudinal studies is more difficult and is more costly. National prevalence surveys, if repeated at intervals, provide a means of monitoring the impact of health and social policies by providing information on trends in DFLE for policy makers. The low level of agreement between long-term disability and self-care disability suggests that use of simple questions on long-standing disability in isolation tends to over-estimate the scale of problems and there is poor agreement between widely used indicators. We believe that simple questions about limiting long-standing illness should be augmented either by additional questions on locomotor disability or replaced by enquiry about basic activities of daily living as these better reflect need for health and social care. Direct comparisons of DFLE between studies are difficult as the levels of DFLE are determined largely by the criteria for disability used. However, studies from demographically developed countries are consistent in highlighting the better DFLE among men. Our study demonstrates only small gender differences in LDFLE and virtually no difference in self-care life expectancy. This may be explained by gender differences in reporting of disability between developed and transitional countries, or may reflect more similar disability profiles between men and women in our study. Optimal circumstances would produce increases in DFLE that are greater than life expectancy and thus a net compression of disability [19], which may be occurring in some circumstances [20]. While it is clear that life expectancy is increasing in most countries of the world there is considerable uncertainty about trends in DFLE. Data are required from more countries and they should be collected more regularly. Wider use of national prevalence studies of disability are needed in all countries. Use of population laboratories may be made in poorer countries that lack the infrastructure for national censuses and surveys [21]. In demographically developing countries national disability surveys may be incorporated into national census procedures or be applied to a sample. REVES (Re´seau Espe´rance de Vie en Sante´), the international network on health expectancy and the disability process, has asked the 2002 International Plan of Action on Ageing to ‘establish indicators of healthy active ageing and of changes in the length of healthy active life to evaluate whether further increases in the quantity of life are accompanied by equivalent increases in quality of life; begin data collection’ [22]. We support this proposal and

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Received 19 March 2002; accepted in revised form 31 January 2003 Downloaded from ageing.oxfordjournals.org by guest on July 12, 2011

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