Contribution of chronic disease to the burden of disability

Abstract

Background: Population ageing is expected to lead to strong increases in the number of persons with one or more disabilities, which may result in substantial declines in the quality of life. To reduce the burden of disability and to prevent concomitant declines in the quality of life, one of the first steps is to establish which diseases contribute most to the burden. Therefore, this paper aims to determine the contribution of specific diseases to the prevalence of disability and to years lived with disability, and to assess whether large contributions are due to a high disease prevalence or a high disabling impact.

Methodology/principal findings: Data from the Dutch POLS-survey (Permanent Onderzoek Leefsituatie, 2001-2007) were analyzed. Using additive regression and accounting for co-morbidity, the disabling impact of selected chronic diseases was calculated, and the prevalence and years lived with ADL and mobility disabilities were partitioned into contributions of specific disease. Musculoskeletal and cardiovascular disease contributed most to the burden of disability, but chronic non-specific lung disease (males) and diabetes (females) also contributed much. Within the musculoskeletal and cardiovascular disease groups, back pain, peripheral vascular disease and stroke contributed particularly by their high disabling impact. Arthritis and heart disease were less disabling but contributed substantially because of their high prevalence. The disabling impact of diseases was particularly high among persons older than 80.

Conclusions/significance: To reduce the burden of disability, the extent diseases such as back pain, peripheral vascular disease and stroke lead to disability should be reduced, particularly among the oldest old. But also moderately disabling diseases with a high prevalence, such as arthritis and heart disease, should be targeted.

Figure 1. Prevalence of disability by age.

The source population consisted of all respondents to the POLS health and labor survey, the Netherlands, 2001–2007, aged 55 and older (n = 17,404). The study population equals the source population minus all subjects who had information missing on the presence of diseases (n = 13,635).

Figure 2. Prevalence of disability by cause.

Abbreviations: CNSLD  =  chronic non-specific lung disease; CVD  =  cardiovascular disease; DM  =  diabetes mellitus; PVD  =  peripheral vascular disease (upper extremity excluded). Contributions of specific diseases to the prevalence of disability were estimated on the basis of diseases prevalence and disabling impact in the study sample from the POLS health and labor survey, the Netherlands, 2001–2007. The disabling impact represents the rate of disability from a specific cause given that the disease is present. Adding specific disability rates for the diseases present and the background rate of disability (by age and gender) gives the total disability rate for a specific exposure group. The contributions of specific diseases presented in the figure add up to the total prevalence of disability.

Figure 3. Life expectancy with disability at age 55 by cause.

Abbreviations: CNSLD  =  chronic non-specific lung disease; CVD  =  cardiovascular disease; DM  =  diabetes mellitus; PVD  =  peripheral vascular disease (upper extremity excluded). Contributions of specific diseases to the life expectancy with disability were estimated on the basis of estimated contributions of specific disease to the prevalence of disability in the study sample from the POLS health and labor survey, the Netherlands, 2001–2007, in combination with life table information for the Dutch population 2001–2007, available from the EHEMU database. Methods of decomposition are described elsewhere (5).