Self-rated health as a predictor of mortality according to cognitive impairment: findings from the Korean Longitudinal Study of Aging (2006-2016)

Abstract

OBJECTIVES: Self-rated health is an instrumental variable to assess the overall health status of a population. However, it remains questionable whether it is still useful for cognitively impaired individuals. Therefore, this study aims to analyze whether self-rated health by the cognitively impaired predicts mortality reliably.METHODS: This study used 7,881 community-dwelling individuals, aged 45 and above, from the Korean Longitudinal Study of Aging (2006-2016). It used the Cox proportional hazard models for analysis. Cognitive status was classified based on the Korean Mini Mental State Examination score and a stratified analysis was used to determine whether the predictability of self-rated health varies according to cognitive status.RESULTS: For cognitively intact individuals, the adjusted hazard ratios (aHR) of mortality were 2.00 (95% confidence interval [CI], 1.18 to 3.41, model 4) for those with ‘bad’ self-rated health and 2.40 (95% CI, 1.35 to 4.25, model 4) for those with ‘very bad’ self-rated heath, respectively, compared with those with ‘very good’ health. The results remain statistically significant even after adjusting for socio-demographic factors, health status, and health-related behaviors. For cognitively impaired individuals, the aHR of mortality was statistically significant for those with ‘very bad’ self-rated health, compared with those with ‘very good’ health, when socio-demographic factors were accounted for (aHR, 3.03; 95% CI, 1.11 to 8.28, model 2).CONCLUSIONS: Self-rated health by cognitively impaired individuals remains useful in predicting mortality. It appears to be a valid and reliable health indicator for the rising population with cognitive impairment, especially caused by aging population.

Can a Single General Self-Rated Health Question Mirror Social Determinant of Health?

“…Although the answer indicates "subjective" health status, which reflects the selfreporting behavior of individual, it is affected by 'objective' or 'actual' health status (8)(9)(10). Self-reported health predicts health conditions such as disability and mortality (11)(12)(13), physical function (14), cardiovascular disease (15), utilization of health services (16) and survival of diseases such as cancers (17). The strength of these connections varies from country to country (18) due to different health related culture.…”

“…Self-reported health predicts health conditions such as disability and mortality ( 11 – 13 ), physical function ( 14 ), cardiovascular disease ( 15 ), utilization of health services ( 16 ) and survival of diseases such as cancers ( 17 ). The strength of these connections varies from country to country ( 18 ) due to different health related culture.…”