The SF-36 as a precursory measure of adaptive functioning in normal aging: the Maastricht Aging Study

Background and aims: Functional independence (FI) is commonly measured by checklist questionnaires that grade whether specific daily living tasks can be performed with or without ancillary assistance. Among older adults who are functioning independently precursory measures of daily living may be useful in gauging how long an individual can remain independent in advanced age. This study examined the SF-36, a standardized self-report measure of health-related quality of life, as a precursory marker of FI in a representative sample of healthy older adults. Methods: The study consisted of 696 Dutch enrollees from the Maastricht Aging Study (MAAS) who were 50 years and older and had been screened for health and cognitive deficits. They were assessed at two time points separated by a nine-year interval on standardized activities of daily living (ADL) and instrumental activities of daily living (IADL) items that measure the presence or absence of assistance need across five functional domains. MAAS enrollees also received the SF-36 at both time points. Results: The SF- 36 Physical Component Summary (PCS) predicted change in ADL/IADL assistance need after nine years (OR 0.94, CI 0.92–0.97). Conclusion: In older adults from MAAS who were otherwise functioning independently at baseline, the SF-36 PCS was a suitable precursory measure of the emergence of assistance need after nine years.