Association between Sarcopenia and Its Longitudinal Changes with all-cause mortality in individuals with Cardiovascular-Kidney-Metabolic syndrome

Background Cardiovascular-kidney-metabolic (CKM) syndrome reflects multiple organ dysfunction and is associated with increased mortality. This study investigated the associations of sarcopenia and its longitudinal progression with all-cause mortality in individuals with CKM syndrome. Methods Participants with CKM syndrome were enrolled from the China Health and Retirement Longitudinal Study (CHARLS) spanning 2011–2020. Cox proportional hazards models and Kaplan-Meier curves were used to evaluate the associations of sarcopenia status, handgrip strength (HGS), skeletal muscle mass index (SMI), and changes in sarcopenia status with all-cause mortality. Restricted cubic spline regressions were conducted to explore potential nonlinear relationships between HGS, SMI and mortality risk. Results Sarcopenia was significantly associated with increased risk of all-cause mortality (HR = 1.455, 95% CI 1.080–1.934). Compared with participants in early CKM without sarcopenia, higher mortality risks were observed in those with early CKM and sarcopenia (HR = 2.181, 95%CI 1.198–3.972), advanced CKM without sarcopenia (HR = 1.984, 95%CI 1.265–3.113) and advanced CKM with sarcopenia (HR = 2.798, 95%CI 1.655–4.729). Both HGS and SMI showed inverse nonlinear associations with mortality, with inflection points at 30.5 kg and 6.82 kg/m ² , respectively. Participants with stable sarcopenia (HR = 2.434, 95%CI 1.102–5.375) or who developed sarcopenia over time (HR = 2.776, 95%CI 1.011–7.623) had significantly higher mortality risks than those with stable no sarcopenia. Conclusions Sarcopenia and its longitudinal progression were independently associated with an increased risk of all-cause mortality in individuals with CKM syndrome. Trial registration: Not applicable.