The Prognostic Significance of Functional Mitral Regurgitation in Patients with Cardiovascular–Kidney–Metabolic Syndrome

Background: Cardiovascular–kidney–metabolic (CKM) syndrome delineates the occurrence of clinical cardiovascular diseases alongside renal or metabolic complications. The prognostic implications of functional mitral regurgitation (FMR) in patients with CKM syndrome remain unclear. This study aimed to elucidate the association and independent impact of FMR regarding clinical outcomes in this population. Methods: In this retrospective cohort study, 1201 patients with CKM syndrome undergoing maintenance hemodialysis between January 2020 and November 2024 were analyzed. Participants were stratified according to the presence and severity of FMR/atrial functional mitral regurgitation (AFMR) into the non-FMR/AFMR, mild FMR/AFMR, and moderate-to-severe FMR/AFMR groups. The primary outcome measure was all-cause mortality. Survival analyses were performed using Kaplan–Meier estimates and multivariate Cox proportional hazard models. Results: FMR prevalence was higher (79.68%) in the CKM cohort. FMR was independently associated with increased all-cause mortality (hazard ratio [HR], 1.831; 95% confidence interval [CI], 1.320–2.541; p = 0.0019). Even mild FMR conferred a significantly elevated risk compared to patients without FMR (HR, 1.699; 95% CI, 1.200–2.405; p = 0.0078). Similarly, AFMR was an independent predictor of mortality (HR, 2.106; 95% CI, 1.349–3.289; p = 0.0046), with moderate-to-severe AFMR associated with a three-fold higher risk (HR, 3.294; 95% CI, 1.007–10.78; p = 0.0027) than non-AFMR. Conclusions: Both FMR and AFMR were found to be independently associated with elevated all-cause mortality in patients with CKM syndrome undergoing hemodialysis. These findings underscore the critical need for early detection and tailored management of mitral regurgitation in this high-risk population to potentially improve outcomes.