Recent trends in disability and functioning among older adults in the United States: a systematic review.

CONTEXT: Several well-publicized recent studies have suggested that disability among older Americans has declined in the last decade.
OBJECTIVES: To assess the quality, quantity, and consistency of recent evidence on US trends in the prevalence of self-rated old age disability and physical, cognitive, and sensory limitations during the late 1980s and 1990s and to evaluate the evidence on trends in disparities by major demographic groups. DATA SOURCES: We searched MEDLINE and AGELINE for relevant articles published from January 1990 through May 2002 and reviewed reference lists in published articles. STUDY SELECTION: From more than 800 titles reviewed, we selected 16 articles based on 8 unique repeat cross-sectional and cohort surveys of US prevalence trends in disability or functioning among persons generally aged 65 or 70 years or older. DATA EXTRACTION: We evaluated survey quality according to 10 criteria, ranked the surveys as good, fair, or poor, and calculated for each outcome the average annual percent change. DATA SYNTHESIS: Among the 8 surveys, 2 were rated as good, 4 as fair, 1 as poor, and 1 as mixed (fair or poor, depending on the outcome) for assessing trends. Analyses of surveys rated fair or good showed consistency of declines in any disability (-1.55% to -0.92% per year), instrumental activities of daily living disability (-2.74% to -0.40% per year), and functional limitations. Surveys provided limited evidence on cognition and conflicting evidence on self-reported ADL (changes ranged from -1.38% to 1.53% per year) and vision trends. Evidence on trends in disparities by age, sex, race, and education was limited and mixed, with no consensus yet emerging.
CONCLUSIONS: Several measures of old age disability and limitations have shown improvements in the last decade. Research into the causes of these improvements is needed to understand the implications for the future demand for medical care.