Primary hyperparathyroidism: incidence and clinical and biochemical characteristics. A demographic study

To give a demographic description of primary hyperparathyroidism (pHPT) in a region in which the incidence of operative treatment was low (2/100,000 inhabitants/year) and to describe the association between histology, biochemistry, and morbidity among the patients.

Retrospective study.

107 consecutive patients who were operated on for pHPT referred for surgery during an 11 year period in a population comprising one million people.

The median weight of adenomas was 1,300 mg (range 200-13,500), weight o hyperplastic tissue removed was median 1,500 mg (range 100-23,800). Weight of abnormal parathyroid tissue correlated significantly with preoperative serum calcium concentration (r = 0.50, p < 0.001). Preoperatively serum immunoreactive parathyroid hormone concentration was correlated with serum calcium concentration (r = 0.39, p < 0.001) and with serum creatinine concentration (r = 0.52 p < 0.001). In a quarter of the patients the serum calcium concentration fell below 2.0 mmol/l after operation. In this subgroup the weight of pathological parathyroid tissue was significantly higher than among those who did not develop hypocalcaemia. Preoperative serum calcium concentration was unrelated to postoperative hypocalcaemia.

Patients from an area in which few operations are done for pHPT had biochemically and clinically advanced disease compared with patients from comparable areas in which more operations are performed. There is a good correlation between biochemistry, organ involvement, and histology. The serum concentration of calcium preoperatively seems to underestimate the presence of advanced disease in patients in whom the bones are affected.