Importance of Hypomagnesemia in Primary Hyperparathyroidism: A Turkish Nationwide Retrospective Cohort Study.

Patients with primary hyperparathyroidism (PHPT) are predisposed to hypomagnesemia as well as hypophosphatemia. In the current literature, scarce data was available on the clinical significance of hypomagnesemia in PHPT. The present study aimed to investigate the prevalence of hypomagnesemia and its association with complications of PHPT in a large nationwide cohort. A nationwide population-based retrospective study was conducted using anonymized data from the Turkish Ministry of Health National Electronic Database (E-nabız). The International Statistical Classification of Diseases and Related Health Problems (ICD)-10 codes were used to identify patient cohort with PHPT (E21) and 96,337 patients with PHPT were reviewed. Female patients (74,650 (77.488%)) comprised the vast majority of the cohort and the mean age was 58.3 ± 15.3 years. It was observed that 38,709 (40.181%) of the patients had osteoporosis and 11,153 (11.577%) had renal stones. The prevalence of hypomagnesemia was 23.783%. While the frequency of osteoporosis increased significantly in patients with hypomagnesemia (45.435% vs. 38.541%, p < 0.0001), there was no difference between the two groups in terms of the frequency of renal stones. In terms of its possible effects on the presence of hypomagnesemia, the presence of osteoporosis, hypercalcemia (≥ 11.2 mg/dL), lower eGFR levels (< 60 mL/min), higher PTH levels (≥ 150 pg/mL), and advanced age (≥ 50 years) were found to be significantly effective in multivariate logistic regression analyses. Hypomagnesemia is observed in approximately one-quarter of patients with PHPT. The presence of hypomagnesemia in a PHPT patient may indicate a more severe form of hyperparathyroidism and an increased risk of osteoporosis.