Association of serum magnesium with cardiovascular mortality and all-cause mortality in peritoneal dialysis patients / 中华肾脏病杂志

ABSTRACT

Objective:To investigate the association of serum magnesium with cardiovascular disease (CVD) and all-cause mortality in peritoneal dialysis patients.Methods:A retrospective study was performed in patients who initiated peritoneal dialysis from January 1, 2013 to July 31, 2019 in the Shaoxing People's Hospital. According to the standard of serum magnesium, the patients were divided into control group (Mg≥0.7 mmol/L) and low-magnesium group (Mg<0.7 mmol/L). The differences in baseline biochemical variables, comorbidities, medications, and clinical outcomes between the two groups were compared. Logistic regression was used to analyze the related factors of hypomagnesemia. Kaplan-Meier survival analysis and Fine-Gray model were used to compare the difference in cumulative survival rate between the two groups. Cox regression model and competitive risk model were used to analyze the risk factors of all-cause mortality and CVD mortality.Results:A total of 381 peritoneal dialysis patients were enrolled in this study. Among them, 321 patients were in control group and 60 patients in low-magnesium group. The total median follow-up time was 27(15, 43) months. There were significant differences in serum albumin, magnesium, phosphorus, intact parathyroid hormone, low-density lipoprotein chloesterol, high sensitivity C-reactive protein and 4-hour dialysate-to-plasma creatinine (4 h D/Pcr) between the two groups. CVD was the main cause of death in patients on peritoneal dialysis. Multivariate logistic regression analysis showed that hypoalbuminemia ( OR=0.901, 95% CI 0.831-0.976, P=0.011), hypophosphatemia ( OR=0.217, 95% CI 0.080-0.591, P=0.003), higher hsCRP ( OR=1.276, 95% CI 1.066-1.528, P=0.008), and higher 4 h D/Pcr ( OR=1.395, 95% CI 1.014-1.919, P=0.041) were independent risk factors for patients with hypomagnesemia. Kaplan-Meier survival curve analysis showed the cumulative survival rate of patients in low-magnesium group was significantly lower than that of control group (Log-rank χ2=5.388, P=0.020). Fine-Gray model analysis showed the cumulative CVD survival rate of low-magnesium group was significantly lower than that of control group ( Gray=6.915, P=0.009). Multivariate-corrected Cox regression model and competitive risk model analysis showed that higher serum magnesium level was a protective factor for all-cause mortality and CVD mortality when serum magnesium was used as a continuous variable ( HR=0.137, 95% CI 0.020-0.946, P=0.044; SHR=0.037, 95% CI 0.002-0.636, P=0.023, respectively). Hypomagnesemia was an independent risk factor for all-cause mortality and CVD mortality when serum magnesium was used as categorical variable ( HR=1.864, 95% CI 1.044-3.328, P=0.035; SHR=2.117, 95% CI 1.147-3.679, P=0.029, respectively). Conclusions:Hypomagnesemia is susceptible to peritoneal dialysis patients with hypoalbuminemia, hypophosphatemia, higher hsCRP and higher peritoneal transport characteristics. Hypomagnesemia is an independent risk factor for CVD mortality and all-cause mortality in peritoneal dialysis patients.