Prevalence and incidence of primary hyperparathyroidism in Bahrain: A retrospective study from one medical center.

Objectives: Primary hyperparathyroidism (PHPT) is considered the third endocrine disorder worldwide. However, the incidence of PHPT is variable in different populations. Since there are no studies on PHPT performed in Bahrain or the surrounding Arab Middle Eastern countries, this study aimed to determine the prevalence and incidence of PHPT and its variants in Bahrain.

Methods: A retrospective study was conducted over a 3-year period (2018-2020) at the Bahrain Defense Force Military Hospital. Patients' data with normal kidney function, age 14 years and older, and had related laboratory results (calcium, PTH, phosphorus, and vitamin D) were retrieved and analyzed for prevalence and incidence of hypercalcemia and PHPT according to age and sex.

Results: Out of 9650 patients, 417 patients had corrected hypercalcemia. Of these, 240, 125, and 88 patients per 100,000 had classic, non-classic, or early/normocalcemic PHPT, respectively. These numbers resulted in a prevalence of PHPT of 274 per 100,000 in Bahrain. The age-adjusted incidence of all types of PHPT was 179 per 100,000/year. Overall, PHPT incidence, whether classic or not, significantly increased in the 50 years age group and above (OR 1.023 with 95% CI 1.013-1.033). Furthermore, hypercalcemia and non-classic PHPT were predominant in females than males. Lastly, vitamin D level was significantly less in classic PHPT than the non-classic variant.

Conclusion: The high prevalence and incidence of PHPT should alarm physicians and clinical practices in Bahrain and the Middle East region to investigate routinely for classic and non-classic PHPT to control and manage the complications that arise from PHPT. However, more epidemiological studies in the Middle East region are warranted to investigate the reasons behind the high incidence of PHPT.