The ability of self-rated health to predict mortality among community-dwelling elderly individuals differs according to the specific cause of death: data from the NEDICES cohort

Background: The biomedical and psychosocial mechanisms underlying the relationship between self-rated health (SRH) and mortality in elderly individuals remain unclear.

Objective: To assess the association between different measurements of subjective health (global, age-comparative, and time-comparative SRH) and cause-specific mortality.

Methods: Neurological Disorders in Central Spain (NEDICES) is a prospective population-based survey of the prevalence and incidence of major age-associated conditions. Data on demographic and health-related variables were collected from 5,278 subjects (≥65 years) in the baseline questionnaire. Thirteen-year mortality and cause of death were obtained from the National Death Registry. Adjusted hazard ratios (aHR) for SRH and all-cause and cause-specific mortality were estimated by Cox proportional hazard models.

Results: At baseline, 4,958 participants (93.9%) answered the SRH questionnaire. At the end of follow-up, 2,468 (49.8%) participants had died, of whom 723 (29.2%) died from cardiovascular diseases, 609 (24.7%) from cancer, and 359 (14.5%) from respiratory diseases. Global SRH independently predicted all-cause mortality (aHR for 'poor or very poor' vs. 'very good' category: 1.39; 95% confidence interval (CI): 1.15-1.69). Analysis of cause-specific mortality revealed that global SRH was an independent predictor for death due to respiratory diseases (aHR for 'poor or very poor' vs. 'very good' category: 2.61; 95% CI: 1.55-4.39), whereas age-comparative SRH exhibited a gradient effect on the risk of death due to stroke. Time-comparative SRH provided small additional predictive value.

Conclusions: The predictive ability of SRH for mortality largely differs according to the specific cause of death, with the strongest associations found for respiratory disease and stroke mortality.