Risk Assessment of Mortality in Elderly Individuals: A Nationwide Cohort Study

Abstract

Introduction: There are several methods that are used to predict emergency room visits or rehospitalization for the elderly. However, existing risk assessment models of mortality in elderly people are limited. The purpose of this study was to ascertain the factors that affect all-cause mortality and to show the risk assessment model of mortality in elderly Koreans. Methods: This was a cohort study conducted using the health checkup data of 246,422 individuals aged >= 60 years, which was provided by the National Health Insurance Service of South Korea between January 1, 2009, and December 31, 2012. The hazard ratios and 95% confidence intervals (CIs) of several conditions and all-cause deaths were estimated using a multivariable Cox proportional hazards model. A nomogram was constructed to visualize the risk factors of mortality; a calibration plot and area under the curve (AUC) were also used to verify the nomogram. Results: Being 85 years or older (100 points) had the greatest influence on all-cause mortality, followed by being underweight (57 points), having more than five chronic diseases (49 points), and ages 78-84 years (45 points); smoking and lack of regular exercise affected mortality to a similar degree. The calibration curves showed good agreement between predictions and observations. The AUC of our nomogram was 0.73 (95% CI: 0.72-0.73). Conclusions: Our results showed the relationship between each condition and mortality rate among elderly individuals in Korea. Our nomogram showed a satisfactory performance in the assessment of the risk of all-cause mortality in elderly Korean people.