Prevalence of hypercalcaemia in normal and in hospital populations.

The purpose of the present study was to review the literature with respect to the prevalence of hypercalcaemia in normal and in hospital populations. Pertinent studies were selected from the MEDLINE database (1980 to March 1995) and through the bibliographies of selected articles. Hypercalcaemia is one of the most common metabolic disorders in malignant diseases and develops in 3-30% of such patients. Hypercalcaemia of malignancy is the most common cause of hypercalcaemia followed by primary hyperparathyroidism in hospital populations. The most common cause in normal populations is primary hyperparathyroidism followed by transient hypercalcaemia. The prevalence of hypercalcaemia shows a large variation in hospital populations ranging from 0.17% to 2.92%. The prevalence in normal populations varies between 1.07% and 3.9% and, surprisingly exceeds the level in hospital populations. The discrepancies between prevalences may be due to varying referral patterns, different distribution of specialities causing different hospital populations and different definitions of hypercalcaemia. Hypercalcaemia presents a diagnostic problem. The percentage of cases of hypercalcaemia that are actually diagnosed has been observed to be as low as 25% in hospitals, in which laboratory results remain unreported unless requested. But even when presented, 20-50% of the cases are overlooked.