Hypomagnesemia Is a Risk Factor for Cardiovascular Disease- and Noncardiovascular Disease-Related Mortality in Peritoneal Dialysis Patients

Purpose: Recent research has shown that hypomagnesemia is associated with increased all-cause mortality in hemodialysis patients. However, the relationship between the long-term prognosis of peritoneal dialysis (PD) and the study is not yet clear. This study will analyze the effects of hypomagnesemia on all-cause, cardiovascular diseases (CVD), and non-CVD mortality in PD patients. Method: In a retrospective cohort study, 1,004 samples were selected from 7 PD centers in China. Based on the baseline blood magnesium level at the beginning of stable dialysis, all patients were classified into blood magnesium <0.7 mmol/L group, 0.7-1.2 mmol/L group, and >1.2 mmol/L group (the end event was death). The Kaplan-Meier method was used to calculate the difference in cumulative survival rate; the Cox proportional hazard model was used to analyze the risk factors of all-cause, CVD, and non-CVD death causes. Results: Cox multiple regression analysis results (reference comparison of 0.7-1.2 mmol/L group): patients with serum magnesium <0.7 mmol/L have a higher risk ratio of all-cause mortality (HR = 1.580, 95% CI: 1.222-2.042, p = 0.001), and it is also obvious after correction by multiple models (HR = 1.578, 95% CI: 1.196-2.083, p = 0.001). Subgroup analysis of the causes of death was as follows: CVD risk (HR = 1.628, 95% CI: 1.114-2.379, p = 0.012) and non-CVD risk (HR = 1.521, 95% CI: 1.011-2.288, p = 0.044). Further analysis of the causes of infection-related death in non-CVD is also significant (HR = 1.919, 95% CI: 1.131-3.1257, p = 0.016). On the other hand, the serum magnesium>1.2 mmol/L group had lower all-cause mortality after correction (HR = 0.687, 95% CI: 0.480-0.985, p = 0.041), and subgroup analysis of the cause of death had no statistical significance (p > 0.05). Conclusions: Hypomagnesemia (serum magnesium <0.7 mmol/L) during stable dialysis in PD patients is a risk factor for CVD- and non-CVD-related mortality, especially infection-related death causes.