Incidence of hypocalcemia and hypercalcemia in hospitalized patients: Is it changing?

Disorders of calcium metabolism are frequently encountered in routine clinical practice. However limited data are available on the epidemiology of hypocalcemia and hypercalcemia in hospitalized patients. Our aim was to evaluate the frequency of hypocalcemia and hypercalcemia in hospitalized patients. This is a retrospective study based on the laboratory results of all hospitalized subjects (n = 12,334) whose calcemia was determined between January 1st, 2011 and December 31st, 2014. Measurements of serum calcium were carried out by a single centralized laboratory. Hypocalcemia was defined as serum calcium levels <8.2 mg/dl and hypercalcemia as serum calcium levels >10.4 mg/dl. Albumin correction was applied to adjust serum calcium values. Overall, hypocalcemia accounted for 27.72% (n = 3420) and hypercalcemia for 4.74% (n = 585) of the 12,334 inpatients. The highest prevalence of hypocalcemia was found in patients over 65 yr. (n = 2097, 61.31%) vs. younger subjects, while the highest prevalence of hypercalcemia was observed in patients aged 0-18 yr. (n = 380, 64.95%). Hypocalcemia was more often encountered in males (n = 1952, 57.07%) while no gender differences were found regarding hypercalcemia. Incidence of hypocalcemia changed over time varying from 35.42% (n = 1061) in 2011 to 21.93% (n = 672) in 2014 (r = -0.98; p = 0.01). Differently, incidence of hypercalcemia did not significantly increase significantly from 3.47% (n = 104) in 2011 to 6.92% (n = 211) in 2014 (r = 0.94; p = 0.052). Despite increased awareness about electrolytes disturbance, physicians should consider calcium levels because of life-threatening consequences associated to hypo- and hypercalcemia. Patient's gender and age could be associated to a different risk of calcium disturbance in hospitalized patients.