Elevated Serum Magnesium Levels May Delay the Loss of Residual Renal Function among Patients Receiving Peritoneal Dialysis: A Prospective Study.

The association between serum magnesium and residual renal function (RRF) among peritoneal dialysis (PD) patients remains unclear. The present study examined the relationships between serum magnesium and the risk of anuria in patients receiving continuous ambulatory peritoneal dialysis (CAPD). This prospective cohort study included 261 PD patients in China. All participants received CAPD for more than 3 months between 2012 and December 2022. Loss of RRF (anuria) was characterized by a 24-h urine output below 100 ml. Cox proportional hazard regression models and competing risk models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for the risk of anuria across different serum magnesium levels. During the median follow-up of 21.3 (15.0-32.4) months, 130 individuals progressed to anuria. The mean concentration of serum magnesium was 0.9 ± 0.15 mmol/L. After multivariate adjustment, the association of serum magnesium with the risk of anuria was not significant in the entire study population. However, for PD patients with better preservation of RRF, the risk of anuria decreases significantly as serum magnesium increases (HR for per standard deviation increment 0.53, 95% CI 0.32-0.88). The protective effect of increased serum magnesium concentrations on RRF was more pronounced among PD patients with lower triglyceride glucose (TyG) index at baseline compared to those with higher TyG index (p for interaction = 0.03). Our results indicated that higher serum magnesium predicts better renal prognosis for PD patients with better preservation of RRF. Levels of TyG index may modulate the relationship.