OBJECTIVES: To measure relative fitness and frailty in older people without specific frailty instruments and to relate that measurement to long-term health outcomes.
DESIGN: Retrospective cohort studies.
SETTING: Two population-based studies of people aged approximately 70 at baseline and followed up to 10 years (in the Canadian Study of Health and Aging (CSHA)) or 26 years in the Gothenburg H-70 cohort study.
PARTICIPANTS: Nine hundred sixty-two men and 1,178 women.
MEASUREMENTS: Deficit accumulation (the exposure) was counted using self-reported (CSHA) or clinically designated (H-70) symptoms, signs, diseases, and disabilities. Relative fitness and frailty were measured in relation to the degree of deficit accumulation evaluated in four quartiles, representing those most fit to those most frail. The items that made up the frailty index were selected randomly without replacement in 1,000 iterations. The outcomes were risks of death or residential long-term care.
RESULTS: Worse frailty, however measured, was associated with worse survival; the Kaplan-Meier curves of random iterations of the frailty definition showed virtually no interquartile overlap for mortality. For any given level of frailty, men died younger than women. Worse frailty was also associated with a higher risk of institutionalization.
CONCLUSION: Frailty appears to be a robust concept that is readily operationalized, with the risk of adverse outcomes being largely established by age 70.