Psychosocial and Health-Related Factors Associated With Discordance Between 13-Year Trajectories of Self-Reported Functional Limitations and Performance-Based Physical Functioning in Old Age.

Objective: The objective of this study was to examine correlates of discordance between 13-year trajectories of self-reported functional limitations and performance-based physical functioning in older adults. Method: We included 2,135 participants from the population-based Longitudinal Aging Study Amsterdam, the Netherlands, followed across 1995-2008. Self-reported functional limitations included six (instrumental) activities of daily living. Performance-based functioning was a composite of four tests. We used latent class growth analysis and multinomial logistic regression to examine discordance and its correlates. Results: Patterns of discordance and concordance (41% concordance, 46% "overestimation" of daily functioning, 13% "underestimation") appeared to be persistent over 13 years. Older age, male sex, cognitive impairment, absence of pain, and light alcohol use were associated with overestimation. Younger age, female sex, and lower self-rated health were associated with underestimation. Discussion: Factors associated with overestimation partly differ from those associated with underestimation. Factors that are highly stable over time are particularly good indicators of persistent discordance.