Hypomagnesemia may be associated with symptomatic disease in patients with primary hyperparathyroidism.

Aim: Magnesium (Mg) homeostasis is closely related to calcium (Ca) metabolism. Hypercalcemia inhibits the reabsorption of Mg from the kidneys, leading to hypomagnesemia. Therefore, patients with primary hyperparathyroidism (PHPT) are predisposed to hypomagnesemia. However, there are few studies on the clinical significance of hypomagnesemia in PHPT. The aim of this study was to retrospectively evaluate the association of hypomagnesemia with the clinical outcomes of PHPT.

Materials And Methods: A retrospective evaluation was made of the data of 538 consecutive patients (478 females, 60 males) diagnosed with PHPT in our center.

Results: The mean age of the study population was 56.5 ± 11.66 years. The mean serum Mg level was 2 ± 0.26 mg/dl. Asymptomatic disease was present in 241 (44%) patients. Symptomatic patients with osteoporosis, Ca level ≥11.2 mg/dl, and estimated glomerular filtration rate (eGFR) < 60 mL/min/1.73 m had lower levels of Mg (p < 0.05). Hypomagnesemia was detected in 129 of 538 patients (23.9%). The patients with hypomagnesemia had a higher rate of symptomatic disease (80% vs. 48%, p < 0.0001). The serum parathormone (PTH) level was found to be higher in patients with hypomagnesemia and the lumbar and femur T-scores and serum vitamin D levels were lower (p < 0.05). Patients with hypomagnesemia had higher rates of kidney stones (34% vs. 21%, p = 0.003) and osteoporosis (74% vs. 32%, p < 0.001). Multivariate logistic regression analysis revealed that hypomagnesemia had a significant effect on the development of symptomatic disease (OR:6.88, CI 95%: 5.20-11.27, p < 0.001).

Conclusions: The current study results demonstrate that hypomagnesemia may be associated with a higher risk of osteoporosis and kidney stones in PHPT patients. Routine evaluation of serum Mg may predict the clinical outcomes of PHPT.