BackgroundThe association between serum β2-microglobulin (β2M) levels and the risk of all-cause and cardiovascular disease (CVD) mortality and the incidence of cardiovascular events (CVEs) in patients undergoing maintenance hemodialysis (MHD) is inconclusive. Furthermore, no study has been performed in China on the significance of serum β2M levels in MHD patients. Therefore, this study investigated the aforementioned association in MHD patients.MethodsIn this prospective cohort study, 521 MHD patients were followed at Dalian Municipal Central Hospital affiliated with Dalian University of Technology from December 2019 to December 2021. The serum β2M levels were categorized into three tertiles, and the lowest tertile served as the reference group. Survival curves were calculated by the Kaplan–Meier method. Hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated using Cox proportional hazard models. Sensitivity analysis was performed by excluding patients with CVD at baseline.ResultsDuring the follow-up period of 21.4 ± 6.3 months, there were 106 all-cause deaths, of which 68 were caused by CVD. When excluding CVD patients at baseline, there were 66 incident CVEs. Kaplan–Meier analysis revealed that the risk of all-cause and CVD mortality in the highest tertile of serum β2M levels was significantly higher than that in the lowest tertile (P< 0.05), but not for the CVEs (P> 0.05). After adjusting for potential confounders, serum β2M levels were positively associated with the risk of all-cause (HR = 2.24, 95% CI = 1.21–4.17) and CVD (HR = 2.54, 95% CI = 1.19–5.43) mortality, and a linear trend was evident (P< 0.05). Besides, the results of sensitivity analysis were consistent with the main findings. However, we didn’t observed the significant association between serum β2M levels and CVEs (P> 0.05).ConclusionThe serum β2M level may be a significant predictor of the risk of all-cause and CVD mortality in MHD patients. Further studies are needed to confirm this finding.