Prevalence, causes and associated mortality of hypercalcaemia in modern hospital care.

Background: Studies examining hypercalcaemia in inpatients were largely published over 20 years ago, and it is likely the epidemiology of hypercalcaemia has changed related to increased lifespan and changes in the prevalence of the underlying causes such as malignancy.
Aim: To explore the epidemiology of hypercalcaemia in a modern tertiary hospital setting in Australia and evaluate the risk of mortality associated with hypercalcaemia.
Methods: A retrospective study was performed in all inpatients with elevated blood calcium levels admitted from July 2013 to June 2018. ICD coding data identified primary diagnoses and mortality. Electronic medical records were reviewed in n = 292 patients admitted across 12 months from January to December 2017, to determine the causes of hypercalcaemia.
Results: Hypercalcaemia occurred in 1819 admissions (0.93% of all hospital admissions), during the 5-year period. The admission primary diagnoses were: malignancy (20% of cases), cardiovascular disease (17%) and gastrointestinal disease (11%). The top causes of hypercalcaemia among the 292 cases where electronic records were reviewed were malignancy (26%), primary hyperparathyroidism (25%) and hyperparathyroidism in the setting of chronic kidney disease (12%). Mortality occurred in 17% of these admissions. Non-survivors had significantly higher calcium levels, phosphate and white cell count, and had lower haemoglobin and albumin levels.
Conclusion: Hypercalcaemia occurred in ~1% of admissions with main causes being malignancy and primary hyperparathyroidism, similar to historical studies. Hypercalcaemia in hospitalised patients is associated with high mortality and higher levels may be a marker for more severe underlying disease.
(© 2021 Royal Australasian College of Physicians.)