Health-related quality of life as a predictor of mortality in heterogeneous samples of older adults

Background Health-related quality of life (HRQoL) is associated with survival in older people with multimorbidities and disabilities. However, older people differ in their characteristics, and less is known about whether HRQoL predicts survival in heterogeneous older population samples differing in their functional, cognitive, psychological or social disabilities. The aim of this study was to explore HRQoL in heterogeneous samples of older men and women, and to explore its prognostic significance for mortality. Methods We analysed combined individual patient data from eight heterogeneous study samples all of which were assessed with the same methods. We used 15D, a generic, comprehensive instrument for measuring HRQoL, which provides a single index in addition to a profile. Two-year mortality was retrieved from central registers. Results Health-related quality of life measurements with 15D were available for 3153 older adults. The mean HRQoL was highest among older businessmen (0.878) and lowest among nursing home residents (0.601). 15D predicted independently and significantly the 2-year survival in the total sample [hazard ratio (HR)/SD 0.44, 95% CI 0.40-0.48)]. However, 15D did not predict mortality in samples of spousal caregivers, lonely older adults and cardiovascular patients. Conclusions 15D captures health and disability factors associated with prognosis whereas in older populations suffering from psychological and social impairments such as caregiver burden or loneliness HRQoL may not reflect their health risks.