Self-rated function, self-rated health, and postmortem evidence of brain infarcts: findings from the Nun Study.

OBJECTIVES: Self-rated function is a new global measure. Previous findings suggest that self-rated function predicts future functional decline and is strongly associated with all-cause mortality. We hypothesized that the strength of the relationship of self-rated function to all-cause mortality was in part due to functional decline, such as would occur with brain infarcts.
METHODS: Self-ratings of function and health (on a 5-point scale, ranging from excellent to poor) were assessed annually on 630 participants in the Nun Study. Mortality surveillance extended from October 31, 1991 to March 1, 1998, and, among those who died, neuropathological examination determined postmortem evidence of brain infarcts. Cox regression modeling with self-rated function and health as time-dependent covariates and stratification by assessment period were used in these analyses.
RESULTS: Self-rated function and health ratings of good, fair, and poor were significantly associated with doubling of the risk of mortality, compared with ratings of very good and excellent. Self-rated function ratings of fair or poor were associated with a threefold increase in the risk of mortality with brain infarcts, but self-rated function and health ratings of fair and poor were comparable in their association with all-cause mortality and mortality without brain infarcts. DISCUSSION: Self-rated function was significantly associated with mortality with brain infarcts, suggesting that brain infarcts may be experienced as functional loss but not recognized or labeled as disease. Our results suggest that self-rated function and health should be explored simultaneously in future research.