Prevalence of type 2 diabetes mellitus in patients with primary hyperparathyroidism

To determine the prevalence of type 2 diabetes mellitus (DM) in patients with primary hyperparathyroidism.

Prevalence of type 2 DM in 609 patients with surgically verified primary hyperparathyroidism presenting between 1992 and 2003 in a tertiary care hospital setting was assessed retrospectively and compared with published data of type 2 DM prevalence in Michigan's general population. Diagnosis of type 2 DM was made on the basis of documentation in the medical record of fasting or random blood glucose level thresholds according to the 1997 American Diabetes Association criteria, history of diabetes mellitus, or therapy with antidiabetic medications.

The crude prevalence rate of type 2 DM in patients with primary hyperparathyroidism was significantly higher than the prevalence in the Michigan general population (15.9% vs 7.8%, respectively; P<.001). However, this difference was not significant after age stratification except for the age group of 64 to 75 years. Because of the differential distribution of participants across age categories in the 2 groups, a standardized prevalence ratio (SPR) was estimated to account for the variance. After adjustment, there was no significant difference in the prevalence of DM between patients with primary hyperparathyroidism and the control population (SPR, 1.19 [95% confidence interval, 0.96-1.45]) except in men.

The reported higher prevalence of type 2 DM in patients with primary hyperparathyroidism could not be confirmed in this large cohort of patients except for in older patients and in men. Because of the retrospective nature the study and the lack of appropriate controls, further studies are needed to confirm or refute these findings.