Risk factors for functional status decline in community-living elderly people: a systematic literature review
Introduction
As recent gerontological studies indicate, health and social care services required by disabled older persons will be a growing burden and a major societal concern for the next century (Beck and Stuck, 1996; Fried and Guralnik, 1997). Although there have been recent reports about a decline in the disability rate among older people in the US, it has been estimated that from 1985 to 2050, the number of disabled older persons in and out of institutions will approximately triple (Manton et al., 1997). A reasonable response to this situation is to devise and implement strategies for preventing or delaying the onset of disability (Fries, 1980; Katz et al., 1983). In fact, trials have confirmed that community-based intervention programs can improve functional outcomes and reduce nursing home admissions in older people (Tinetti et al., 1994; Stuck et al., 1995Stuck et al., 1997). To meet the impending challenge of the 21st century, strategies for disability prevention must now be further developed.
The first step in this process is to delineate what factors convincingly lead to the development of disability. Although multiple studies have addressed this issue, the high variability among them in terms of such matters as study design and methodology makes it difficult to extract a coherent, dependable list of factors from which to develop prevention strategies. We therefore conducted a formal, systematic literature review of all longitudinal studies analyzing the association of individual risk factors with functional status outcome in community-living older subjects. The theoretical model we employed for the task of summarizing and giving structure to the evidence is the widely cited one proposed by Verbrugge and Jette (1994), a modification of a WHO model further adapted by the Institute of Medicine (World Health Organization, 1980; Pope and Tarlov, 1991). This model helps us isolate the multiple, often intertwined biological, psychological, functional, social and environmental factors that contribute to the development of disability.
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Data sources
Published studies were identified through searches of MEDLINE, PSYCINFO (Psychological Abstracts), SOCA (Sociological Abstracts) and EMBASE (Excerpta Medica) databases for the period from 1985 to 1997. Keyword, title and abstract information were used. The main search terms were `aged', `disab#' (the symbol is used for identifying all words starting with disab, e.g. disability, disabled, disablement), `impaired' or `limit#', `decline' combined with `function#' and `study' or `trial'. The
Description of included studies (Table 1)
Table 1 presents the characteristics of the 78 included studies predicting functional status outcome in older persons. Many studies were secondary analyses of databases from large longitudinal studies such as the Alameda County study, the EPESE (Established Populations for Epidemiologic Studies of the Elderly) study, the Framingham study, the LSOA (Longitudinal Study of Aging), the MHCPS (Massachusetts Health Care Panel Study) and the NHANES Survey (National Health and Nutrition Examination
Synthesis for main risk factors (Table 3)
We use the domain `affect' as an example to explain the data listed in Table 3 and to describe the synthesis process that was performed for each domain. As listed in Table 3, 21 of the 78 included longitudinal studies reported results of the prediction of functional status decline with at least one measure of affect. These studies originated from 14 different longitudinal databases, implying that some studies originated from the same databases. The 21 studies reporting results for the risk
Specific conditions and clinical findings (Table 4)
Many studies reported the impact of self-reported conditions and clinical findings on functional status outcome. There were two limitations with regard to rating the conditions and clinical findings as predictors of functional status decline. First, the definitions of conditions and clinical findings were extremely variable and pooling of the findings about symptoms would therefore have been misleading. Second, the statistical control for confounding was extremely variable between studies,
Socio-demographic factors
Socio-demographic factors show strong associations with functional status in both longitudinal and cross-sectional studies. Chronological age is probably the most important factor, with an increase in the relative risk of functional status decline of about 2.0 for each 10-year increase in age (Guralnik et al., 1993). The risk of new onset disability is similar between men and women if other factors such as chronic conditions are controlled for in the multivariate models (Guralnik and Kaplan,
Interactions between risk factors
Only few of the included studies addressed interactions between individual risk factors. Laforge et al. (1992)reported that the combination of hearing and vision impairment had a higher impact on subsequent functional status as compared to each impairment alone. LaCroix et al. (1993)demonstrated that the association of alcohol use with functional status differed between subjects with and without baseline chronic conditions. The interactive effects of emotional and social support is an other
Strength of association
Our definition of strength of evidence quantifies the presence, number and quality of statistically significant associations between risk factors and functional outcomes. It does not, however, measure the strength of the association between risk factors and functional outcomes. Several studies attempted to estimate the relative impact of various chronic conditions or impairments on functional status decline. For this purpose, we reviewed all included longitudinal and all excluded
Limitations of this review
A literature review designed to synthesize the current scientific evidence for risk factors for functional status decline faces two major problems. First is the variability of numerous features of the studies under investigation from the selection and definition of study populations, predictors, outcome variables and analytic designs to the lack of a uniform definition of functional status decline (Wiener et al., 1990). This lack of a uniform definition is perhaps the most troubling variable of
Conclusions
To our knowledge this is the first published comprehensive literature review on risk factors for functional status decline. Although there were multiple methodological challenges, it was possible to define a framework for this review and list the main risk factors for functional status decline based on empirical research data (Table 3). The review confirms that there is empirical evidence for an association among biological, psychological and social risk factors and the development of
Acknowledgements
The authors would like to thank Margret M. Baltes, Ph.D., Free University, Berlin, Germany; Dorly J.H. Deeg, Ph.D., Free University, Amsterdam; Steven Iliffe, MRCGP, Department of Primary Care and Population Sciences, Royal Free Hospital School of Medicine, London; C. Lucke, M.D., Hagenhof Clinic for Rehabilitation, Langenhagen, Germany, Marianne Schroll, M.D., Department of Geriatrics, Copenhagen, Denmark; Cameron G. Swift, M.D., Health Care of the Elderly, King's College Hospital, London; and
References (152)
- et al.
Gender and inequalities in health in later life
Social Science and Medicine
(1993) - et al.
High, usual and impaired functioning in community-dwelling older men and women: findings from the MacArthur Foundation Research Network on Successful Aging
Journal of Clinical Epidemiology
(1993) - et al.
Predictors of 10-year change in physical, cognitive and social function in Japanese elderly
Archives of Gerontology and Geriatrics
(1992) - et al.
Long-term physical functioning in persons with knee osteoarthritis from NHANES I: effects of comorbid medical conditions
Journal of Clinical Epidemiology
(1994) - et al.
Mini-mental state: a practical method for grading the cognitive state of patients for the clinician
Journal of Psychiatric Research
(1975) - et al.
Physical disability in older adults: a physiological approach
Journal of Clinical Epidemiology
(1994) - et al.
Marital status and health among the elderly
Social Science and Medicine
(1995) - et al.
Predictive value of life events, psychosocial factors and self-rated health on disability in an elderly rural French population
Social Science and Medicine
(1988) - et al.
Measuring functional status: cross-sectional and longitudinal associations between performance and self-report
Journal of Clinical Epidemiology
(1996) - et al.
Predictors of physical disability after age 50: six-year longitudinal study in a runners club and a university population
Annals of Epidemiology
(1994)
The Framingham disability study: physical disability among community-dwelling survivors of stroke
Journal of Clinical Epidemiology
Maintenance of functioning in the elderly
Annals of Epidemiology
Predictors of physical disability in elderly blacks and whites of the Charleston Heart study
Journal of Clinical Epidemiology
Predictors of disability in elderly Finnish men: a longitudinal study
Journal of Clinical Epidemiology
The effect of medical conditions on the functional limitations of Mexican–American elderly
Annals of Epidemiology
Risk of functional decline among well elders
Journal of Clinical Epidemiology
Predictors of function among older Hispanic immigrants: a five-year follow-up
Nursing Research
Compendium of physical activities: classification of energy costs of human physical activities
Medicine and Science in Sports and Exercise
The timing of change: patterns in transitions in functional status among elderly persons
Journal of Gerontology, Social Sciences
Changes in functional ability from ages 70 to 75
Journal of Aging and Health
Preventing disability: beyond the black box
JAMA
Social networks, host resistance and mortality: A nine-year follow-up study of Alameda County residents
American Journal of Epidemiology
Les incapacités au cours du vieillissement: approche descriptive et facteurs de risque: enquête longitudinale sur 4 ans dans une population rurale âgée
Revue d'Epidemiologie et de Santé Publique
The relation of dizziness to functional decline
Journal of the American Geriatrics Society
Chronic conditions that lead to functional limitation in the elderly
Journal of Gerontology, Medical Sciences
Associations with changes in level of functional ability: results from a follow-up survey at two and a half years of people aged 85 years and over at baseline interview
Ageing and Society
Health practices and incident disability among the elderly
American Journal of Public Health
The implications for everyday life of incident self-reported visual decline among people over age 65 living in the community
Gerontologist
The impact of depressive symptomatology on physical disability: MacArthur studies of successful aging
American Journal of Public Health
Functional ability in the oldest old: cumulative impact of risk factors from the preceding two decades
Journal of Aging and Health
Evolution de l'état de santé d'un groupe de retraités de la région parisienne selon la pratique d'une activité physique
Revue d'Epidemiologie et de Sante Publique
ADL dependence and medical conditions in Chinese older persons: a population-based survey in Shanghai, China
Journal of the American Geriatrics Society
Longitudinal analysis of functional disabilities in older men
Journal of Gerontology
The effect of walking on lower body disability among older blacks and whites
American Journal of Public Health
Knee osteoarthritis and physical functioning: evidence from the NHANES I epidemiologic followup study
Journal of Rheumatology
The Hopkins Symptom Checklist (HSCL): a self-report symptom inventory
Behavioral Science
Mortality, disability and falls in older persons: the role of underlying disease and disability
American Journal of Public Health
Repeatability and objectivity of various measurements in rheumatoid arthritis
Arthritis and Rheumatism
Spurious precision? Meta-analysis of observational studies
British Medical Journal
Hospital diagnoses, medicare charges and nursing home admissions in the year when older persons become severely disabled
JAMA
Functional decline in older adults: expanding methods of ascertainment
Journal of Gerontology—Medical Sciences
Disability in older adults: evidence regarding significance, etiology and risk
Journal of the American Geriatrics Society
Aging, natural death and the compression of morbidity
New England Journal of Medicine
Medical conditions differentially affect the development of IADL disability: implications for medical care and research
Gerontologist
Depression without sadness: functional outcomes of nondysphoric depression in later life
Journal of the American Geriatrics Society
Assessing risk for the onset of functional dependence among older adults: the role of physical performance
Journal of the American Geriatrics Society
Impairments in physical performance and cognitive status as predisposing factors for functional dependence among nondisabled older persons
Journal of Gerontology, Medical Sciences
A predictive model for ADL dependence in community-living older adults based on a reduced set of cognitive status items
Journal of the American Geriatrics Society
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