To evaluate the relationship between serum magnesium and parathyroid hormone levels in peritoneal dialysis and hemodialysis patients.

OBJECTS: This study aimed to determine the relationship between magnesium and PTH levels in peritoneal dialysis (PD) and hemodialysis (HD) patients.

METHODS: This cross-sectional study was performed on HD and PD patients in Kerman, Iran. After recording demographic and clinical data, the pre-dialysis levels of hemoglobin, 25-hydroxy vitamin D, ferritin, creatinine, calcium, phosphorus, albumin, PTH, and magnesium were measured for all patients. The P value of less than 0.05 was considered statistically significant.

RESULTS: Magnesium levels in PD patients were significantly higher than in HD patients (P < 0.001). The median PTH level in PD patients was significantly lower than in HD patients (P = 0.046). The correlation between PTH and serum magnesium levels was not significant in PD or HD patients. In the regression model, dialysis modality (PD or HD) was the only significant variable in determining serum magnesium levels (P = 0.005).

CONCLUSION: Magnesium is a neglected ion in peritoneal dialysis and hemodialysis patients. In dialysis centers that use a dialysate with standard magnesium concentration (0.5 mmol/L in HD and 0.75 mmol/L in PD), special attention is necessary to hypomagnesia and its complications because magnesium levels in PD patients were significantly higher than in HD patients. As the correlation between magnesium and PTH levels in both PD and HD patients were not significant, the association of high magnesium levels with low PTH in PD patients should be considered in terms of increasing the potential for adynamic bone disease. It seems that ordering serum magnesium in the routine tests of dialysis patients is necessary.