Association of Serum Magnesium with Gastrointestinal Bleeding in Peritoneal Dialysis Patients: a Multicentre Retrospective Study.

Serum magnesium is involved in the process of blood coagulation, and low serum magnesium is associated with haemorrhagic diseases. No studies have explored the relationship between serum magnesium and gastrointestinal bleeding (GIB). This study aimed to explore the association between serum magnesium and GIB in peritoneal dialysis (PD) patients. This was a multicentre retrospective cohort study. The primary endpoint was GIB. According to the baseline serum magnesium level of 0.7 mmol/L, patients were divided into two groups: the hypomagnesaemia group and the nonhypomagnesaemia group. A multivariate Cox regression model was used to investigate the association between hypomagnesaemia and GIB. A total of 654 PD patients from four Chinese peritoneal dialysis centres were recruited from February 1, 2010 to January 31, 2020. During the follow-up, 47 patients experienced GIB. Kaplan-Meier curves showed that there was a significant difference in the risk of GIB between the two groups (log-rank = 11.82, P < 0.001). The multivariable Cox regression model showed that the risk of GIB was higher in the hypomagnesaemia group than the nonhypomagnesaemia group after adjustment for demographic variables and laboratory indicators (HR = 3.007, 95% CI 1.488-6.079, P = 0.002). A baseline lower serum magnesium level was associated with a higher risk of GIB in PD patients.