Remnant Cholesterol Inflammatory Index and its Association With Cardiometabolic Multimorbidity in Middle-Aged and Advanced-Aged Individuals: Evidence From the China Health and Retirement Longitudinal Study

Background:The association between remnant cholesterol inflammatory index (RCII) and cardiometabolic multimorbidity (CMM) remains unclear.RCII is defined as: {Total Cholesterol -(High-Density Lipoprotein Cholesterol + Low-Density Lipoprotein Cholesterol)] × High-Sensitivity C-Reactive Protein/10}.This study examined the association between baseline RCII and CMM among middle-aged and older adults in China. Material/Methods:This study analyzed data from the China Health and Retirement Longitudinal Study (CHARLS), including 6173 participants.CMM was defined as the coexistence of at least 2 of 4 conditions: hypertension, diabetes, heart disease, or stroke.Participants were grouped according to the quartiles of natural log-transformed RCII (ln-RCII) values.Modified Poisson regression models, restricted cubic splines, and receiver operating characteristic curves were used to examine the relationship between lnRCII and CMM outcomes. Results:In the cohort, 1832 cases of CMM occurred, and the incidence of CMM was highest in the lnRCII highest-quartile group (P < 0.001).In the fully adjusted model, each unit of increase in lnRCII was associated with a higher risk of CMM (RR = 1.13, 95% CI: 1.09-1.16),and participants in the highest quartile had a higher risk than those in the lowest quartile (RR = 1.69, 95% CI: 1.50-1.90).The area under the curve for lnRCII was 0.607 (95% CI: 0.592-0.622),indicating modest discriminatory ability.Conclusions:Higher baseline lnRCII was associated with an increased risk of incident CMM in middle-aged and older Chinese adults.Although RCII may capture combined information on remnant cholesterol and inflammation, its clinical predictive value requires further validation.