High serum 2-microglobulin is a significant predictor of mortality in maintenance hemodialysis patients

Background: Beta2-microglobulin, a novel marker of kidney function, predicts kidney failure and mortality in the general population. However, few studies have evaluated the association of serum beta 2-MG level with clinical outcome in maintenance hemodialysis (MHD) patients. Methods This prospective cohort study enrolled 303 MHD patients to investigate the factors related to beta 2-MG and its relationship to mortality in MHD patients. Multivariate linear regression analysis was used to examine the factors related to beta 2-MG level. Multivariable Cox regression was used to calculate the hazard ratios for beta 2-MG on all-cause and cardiovascular mortality. Results: The median value of serum beta 2-MG was 44.6 mg/L (interquartile range 37.60-50.40 mg/L). During the follow-up period of 24 months, there were 48 all-cause deaths (23.0%), including 36 cardiovascular causes (75.0% of all deaths). Multiple linear regression showed that dialysis duration, serum creatinine, and alkaline phosphatase were independent predictors of serum beta 2-MG level. Kaplan-Meier analysis revealed that mortality in MHD patients was significantly higher in low albumin patients with beta 2-MG > 44.6 mg/L. Cox regression analysis showed that beta 2-MG was a significant predictor of all-cause mortality (HR = 1.122, 95% CI: 1.058-1.190, rho < 0.001) and cardiovascular mortality (HR = 1.145, 95%CI: 1.065-1.123, P < 0.001) in MHD patients with low albumin level after adjusting for confounding factors. However, our results showed that serum beta 2-MG was not associated with mortality in MHD patients with normal albumin level. Conclusion: These results are supportive of the potential role of the serum beta 2-MG level as a predictor of mortality in MHD patients with low albumin.