Does Self‐Rated Health Predict Survival in Older Persons with Cognitive Impairment?

OBJECTIVES: To determine whether baseline self-rated health (SRH) independently predicted survival in an older Canadian population and to investigate the role of cognition on the SRH-mortality relationship. DESIGN: Population-based prospective cohort study. SETTING: Ten Canadian provinces, community-based. PARTICIPANTS: A total of 8,697 community-dwelling participants aged 65 and older. MEASUREMENTS: Self-reported measures of overall health, physical function, comorbidities, and demographic characteristics were obtained by interview. Cognitive ability was ascertained using the Modified Mini-Mental State Examination (3MS). Participants were followed for their survival status from the initial interview in 1991 until October 31, 1996. RESULTS: Subjects with reports of poor SRH were significantly more likely to die during follow-up than those reporting good SRH, after adjusting for relevant covariates (adjusted hazard ratio (AHR)=1.38, 95% confidence interval (CI)=1.24-1.53). SRH was also related to other measures of health status across levels of cognitive impairment. SRH remained a significant predictor of mortality in subjects with mild to moderate cognitive impairment (AHR=1.26, 95% CI=1.01-1.59) but not in those with severe cognitive impairment (AHR=1.00, 95% CI=0.76-1.31). CONCLUSION: This study supports the utility of SRH assessments in predicting survival of individuals with mild to moderate cognitive impairment. The findings highlight the potential role of complex cognitive processes underlying the SRH-mortality relationship.