Analysis of hypercalcemia in hospitalized patients in Spain from 2001 through 2015

Few studies have explored the characteristics of hospitalized patients with hypercalcemia. Our goal was to analyze clinical-epidemiological features, mortality, and incidence of hypercalcemia in Spanish adult inpatients.

We conducted a retrospective study using Spain's nationwide hospital database ("Conjunto Mínimo Básico de Datos Hospitalización", CMBD-H), analyzing all hospital discharges from 2001 through 2015. Hypercalcemia was defined according to ICD-9-CM code 275.42. We examined causes, sex, median age, length of stay, and in-hospital mortality. Annual rates, adjusted for age and sex, were analyzed too.

A total of 41,103 cases of hypercalcemia were analyzed out of 59,978,703 hospital discharges. Median age was 70 (interquartile range [IQR], 59-79), with 51.3% males. Internal Medicine had the most discharges (32.8%). Hypercalcemia was the leading cause in 11.4% of cases. Most common etiologies were cancer (83.8%) and hyperparathyroidism (15.1%). Neoplasms were more prevalent in males and older patients. Mean incidence was 0.7/1000 admissions, with a 7.1% annual growth rate. The overall in-hospital mortality rate was 27.1%, which remained unchanged over the study period. Factors associated with mortality included increasing age (OR, 1.01; 95% CI, 1.01-1.02), male sex (1.60; 1.53-1.68), emergency admission (1.43; 1.34-1.52), hypercalcemia as main diagnosis (1.89; 1.74-2.06), and neoplasm (5.24; 4.92-5.58).

This is the largest and most comprehensive general study on in-hospital hypercalcemia conducted to this date. The rate of hypercalcemia in hospitalized patients is increasing, likely due to the growing number of cancer inpatients. Hypercalcemia was associated with high mortality.