The incidence and causes of hypercalcaemia.

A prospective screen for hypercalcaemia in 58,053 hospital in-patients was conducted over 12 months. The incidence of hypercalcaemia was 0.6%, being transient in 19.2% of patients and sustained in the remainder. The most common causes in the sustained group were malignancy (45%) and primary hyperparathyroidism (16.5%). The incidence of primary hyperparathyroidism was 78/100,000 hospital in-patients, and its discovery was directly attributable to the survey in over half the cases.