Effect of Surgery on Cardiovascular Risk Factors in Mild Primary Hyperparathyroidism

Abstract

Mild primary hyperparathyroidism (pHPT) seems to have a good prognosis, and indications for active treatment (surgery) are widely discussed. The extraskeletal effects of PTH, such as insulin resistance, arterial hypertension, and cardiovascular (CV) risk, may however be reversible by operation. Our aim was to study biochemical markers of bone turnover, indices of the metabolic syndrome, and various risk markers for CV disease in patients with mild pHPT randomized to observation without surgery or operative treatment and followed for 2 yr. A total of 116 patients (mean age, 63 +/- 8 yr; 19 men and 97 women) who on May 1, 2008, had performed the 2-yr visit in a randomized study on mild pHPT (serum calcium at baseline, 2.69 +/- 0.11 mmol/liter) and where frozen samples were available from baseline and follow-up participated in the study. Calcium and PTH levels were normalized after surgery, and biochemical markers of bone turnover decreased by 35%, followed by a significant increase in BMD in the spine (2.7%; P < 0.01) and femoral neck (1.1%; P < 0.02) compared with the observation group. No significant differences were observed between the groups for blood pressure, markers of insulin resistance, detailed cholesterol metabolism, adipokines, or parameters of inflammation and CV surrogate markers. We observed expected effects on biochemical markers of bone turnover and bone mass after surgical treatment of mild pHPT, with stable values in the group randomized to observation. For a variety of measures of the metabolic syndrome, adipokines, and CV risk factors, no benefit of operative treatment could be demonstrated. Neither did we observe any deleterious effects of conservative management in the 2-yr perspective.