Abnormalities of serum magnesium levels in dialysis patients undergoing parathyroidectomy

In primary hyperparathyroidism, postoperative hypocalcemia can be exacerbated by magnesium deficiency. However, the significance of magnesium homeostasis in surgery for secondary hyperparathyroidism is unknown. In this study, 268 consecutive adult patients on renal replacement therapy who underwent parathyroidectomy for secondary hyperparathyroidism were included for analysis. We found that about one fifth presented with hypomagnesemia (5.6%) or hypermagnesemia (14.6%). Hypomagnesemia was associated with lower calcium levels and longer postoperative hospital stays. Hypermagnesemia was associated with higher calcium-phosphorus products and lower parathyroid hormone levels. In multivariate analysis, patient age, alkaline phosphatase, and osteocalcin were independent predictors of prolonged stay after parathyroidectomy. There was a positive correlation between serum magnesium levels and severity of itching in these patients. Calcium-phosphorus products and serum magnesium levels were independently associated with pruritus. In conclusion, magnesium abnormalities play a minor role in hungry bone syndrome after parathyroidectomy for secondary hyperparathyroidism. Patients with higher serum magnesium levels had greater severity of pruritus.