Psychological health in a modified life's Crucial 9 score: Association with all-cause mortality and comparison with LE8

Abstract

Background: The inclusion of Psychological Health in the Life's Essential 8 (LE8) may improve its predictive validity and contribute to a more equitable assessment of mortality by better accounting for this crucial component. Therefore, this study aimed i) to assess the longitudinal association between a modified version of Life's Crucial 9 (LC9) score and all-cause mortality in the Chilean population and ii) to examine whether adding psychological health to the original LE8 framework might enhance its predictive ability.

Method: We included 3,546 participants aged ≥15 from the Chilean National Health Survey 2016-2017. Mortality was ascertained through linkage with the Chilean Civil Registry and Identification. A modified version of the LC9 score was created and divided into quartiles. The modified version was calculated from nine health and behavioral components, incorporating a Psychological Health variable (composite of depression and social integration). The association between LC9 and all-cause mortality was examined using crude Kaplan-Meier survival curves and Cox proportional hazard models adjusted for sociodemographic and lifestyle factors. Non-linear associations were explored using restricted cubic splines. Predictive performance of LC9 was further compared with LE8 using model fit criteria (AIC, BIC) and discrimination measures (C-statistics, ROC-AUC).

Findings: Over a median follow-up of 5 years, 169 participants (4.8 %) died from any cause. Survival curves showed lower survival probabilities among individuals in the lowest LC9 quartile than to those in higher quartiles (log-rank <0.001). Compared with participants in Q1, those in Q4 had a 49 % lower risk of all-cause mortality after full adjustment for confounders (HR: 0.51; 95 % CI: 0.31-0.82). When comparing indices, LC9 (C-statistics= 0.854 (95 % CI: 0.842-0.866) provided marginally better model fit than LE8 (C-statistics= 0.851 (95 % CI: 0.839-0.864), but their overall predictive performance for mortality was similar.

Interpretation: Higher LC9 scores were associated with lower all-cause mortality. The incorporation of Psychological Health measures may slightly improve the prediction of the models.

Keywords: Life’s Crucial 9; Life’s essential; Mortality; Predictive.