Metabolic abnormalities related to cardiovascular risk in primary hyperparathyroidism: effects of surgical treatment.

OBJECTIVES

Untreated primary hyperarathyroidism (pHPT) is accompanied by an excessive morbidity in circulatory disorders, associated with blood pressure and diabetes. The aim of the present study was to further penetrate the impact of pHPT on glucose, urate, lipid and lipoprotein concentrations, known to be interrelated metabolic cardiovascular risk factors.

DESIGN

Longitudinal study of patients with pHPT before and 1 year after surgical treatment.

SETTING

Departments of Internal Medicine and Surgery, Lund University Hospital.

SUBJECTS

One hundred and seventeen consecutive patients with pHPT referred to surgical treatment. At presentation. 11 patients had previously diagnosed diabetes mellitus.

INTERVENTION

All patients were successfully operated for pHPT.

MAIN OUTCOME MEASURES

Fasting blood glucose and serum concentrations of cholesterol, triglyceride and urate were determined before and 1 year after surgery. The concentration of LDL- and HDL-cholesterol was separately analyzed in 21 cases. These data as well as the systolic and diastolic blood pressure were related to intact PTH and ionized calcium at presentation. Glomerular filtration was separately measured pre-operatively and related to the urate values.

RESULTS

While the mean value for glucose remained unchanged among 11 patients with previously diagnosed diabetes at presentation, a significant decrease of glucose from 5.03+/-0.13 to 4.71+/-0.08 mmol/L (P < 0.05) was found among patients without known diabetes. Out of these patients, eight had diabetic glucose values at presentation, decreasing from 8.35+/-0.54 to 5.10+/-0.35 mmol/L (P < 0.05), and 12 had glucose values indicating impaired glucose tolerance, decreasing from 5.94+/-0.06 to 5.10 +/-0.38 mmol/L (P < 0.05) after surgery. Total cholesterol and trigylceride concentrations were not changed. However, male patients had significantly lower triglyceride levels at follow-up, 1.16+/-0.09 mmol/L compared to 1.57+/-0.14 mmol/L before surgery (P < 0.05). Significantly lower triglyceride values were also found among patients with glucose values indicating impaired glucose tolerance at presentation. The LDL/HDL cholesterol ratio remained normal. The serum level of urate decreased in both male and female patients after surgery, and was positively correlated to the PTH and ionized calcium values and inversely correlated to renal function before treatment. There was no significant correlation between calcium or PTH and the other metabolic variables studied.