Effect of serum albumin on cardiac-related events in end-stage kidney disease with mitral regurgitation initial hemodialysis

Mitral regurgitation (MR) and hypoalbuminemia are prevalent in patients with end-stage kidney disease who are initiating hemodialysis (HD) and are associated with adverse cardio-vascular outcomes. However, the combined impact of serum albumin levels and MR severity on cardiac prognosis in this population remains unclear. This study aimed to investigate the influence of serum albumin level on cardiac-related outcomes in incident HD with MR. This single-center retrospective study enrolled 217 patients with ESRD patients who initiate maintenance HD at the First People's Hospital of Zunyi between March 2020 and February 2025. Patients were categorized into the none/mild MR (MR- group, n = 158) and moderate/severe MR (MR+ group, n = 59) groups based on MR severity, according to transthoracic echocardiography data. The competitive risk model and the Fine-Gray test were used to assess the impact of MR severity and serum albumin level on cardiac-related events. Subgroup and interaction analyses were performed to evaluate the impact of different factors on endpoint events. The prevalence of moderate/severe MR was 27.2%. The median follow-up duration was 20.7 months. Multivariate competing risk model analysis revealed that moderate/severe MR was an independent risk factor for cardiac-related events (subdistribution hazard ratio 2.188, 95% confidence interval 1.187-4.034; P = .012). Concurrently, higher serum albumin levels were an independent protective factor against cardiac-related events (per 1 g/L increase: subdistribution hazard ratio 0.914, 95% confidence interval, 0.871-0.959; P < .001). Subgroup analysis showed that the association between moderate/severe MR and increased cardiac event risk was stronger in patients with low serum albumin level (<35 g/L) (P interaction < .001), indicating a significant synergistic effect between low albumin levels and moderate/severe MR in increasing cardiac risk. Both moderate/severe MR and low serum albumin level are independent risk factors for cardiac events in patients initiating HD. Critically, low serum albumin levels significantly potentiate the adverse cardiac risk associated with moderate/severe MR. Interventions targeting serum albumin levels may improve cardiovascular outcomes in this high-risk subgroup.