Relationship Between Cardiometabolic Index and Incident Frailty in Middle-Aged and Older Adults: A Cohort Study

IntroductionThe cardiometabolic index (CMI), a comprehensive indicator for assessing body fat distribution and serum lipid level, has been found to be associated with biological aging. But the potential relationship between CMI and incident frailty remains unclear. Herein, we designed this study to delve into the relationship between CMI and frailty incidence in adults aged 45 years or older.MethodsData were obtained from the China Health and Retirement Longitudinal Study (CHARLS). Participants were categorized into quartiles (Q1-Q4) according to CMI levels. Multivariable logistic regression model and restricted cubic spline (RCS) analyses were performed to evaluate the connection between CMI and incident frailty risk. In addition, we conducted subgroup and interaction analyses to investigate heterogeneity across distinct subgroups.ResultsA total of 6200 participants were enrolled in our study, with an average age of 57.92 ± 8.57 years, 48.64% males. During a 7-year follow-up, 1166 (18.81%) participants developed frailty, and the incidence showed an increasing trend from Q1 to Q4. The fully adjusted odds of developing frailty increased by 1% for per 1-SD increment in CMI (OR = 1.02, 95% CI:1.00-1.03, P = 0.005). The participants with the highest CMI quartile (Q4) had a significantly elevated risk of developing frailty compared to those in the lowest CMI group (Q1) (OR = 1.06, 95% CI:1.02-1.09, P < 0.001). Subgroup analyses demonstrated consistent results across various subgroups (P for interaction > 0.05). The RCS analysis confirmed a positive association of CMI with incident frailty, and nonlinear relationship was observed (P for overall < 0.001, P for nonlinear = 0.012).ConclusionHigher CMI levels were associated with an increased likelihood of developing frailty. Given its accessibility, CMI may have potential value as a population-level marker for frailty risk assessment.