Cardiovascular risk factors in primary hyperparathyroidism

Severe primary hyperparathyroidism (PHP) has been associated with increased cardiovascular morbidity. Such an association in mild PHP is not known. We conducted a cross-sectional study to assess the correlation between mild and traditional PHP and emergent cardiovascular risk factors.

A total of 139 patients with PHP (72 with severe PHP and indications for parathyroidectomy, 67 with mild PHP and no indications for surgery) and 111 control subjects, of similar age and body weight, were enrolled in this study. Participants had measurement of fasting blood levels of calcium, PTH, insulin, glucose, total cholesterol, HDL-cholesterol, LDL-cholesterol, triglycerides, interleukin-6, and C-reactive protein. Body mass index (BMI), waist and hip circumferences, blood pressure, homeostasis model assessment 2-insulin resistance index (IR) and the presence of metabolic syndrome (MS) were evaluated.

Severe PHP patients had significantly higher rates of MS (37.5%), IR (38.9 %) vs mild PHP (34.3 and 23.9%, respectively) and controls (14.4 and 14.4%, respectively). Multivariate logistic-regression model, adjusted for age and BMI, and for age and waist size, revealed that severe PHP had significantly higher likelihood of cardiovascular risks [odds ratio (OR) 3.5, 95% confidence interval (CI) 1.5-8.125, p=0.004 for MS, and OR 3.7, 95% CI 1.64-8.29, p=0.002 for IR]. Serum calcium significantly predicted the presence of MS (OR 1.875, 95% CI 1.259-2.793, p=0.002) and IR (OR 2.043, 95% CI 1.365-3.057, p=0.002).

Greater probability of MS and insulin resistance was observed in patients with severe PHP. Serum calcium is a predictor of these cardiovascular risk factors.