Parenteral calcium administration and outcomes in critically ill patients with hypocalcemia: A retrospective cohort study.

Background: Hypocalcemia is common among patients admitted to the intensive care unit (ICU). The administration of calcium in critically ill patients with hypocalcemia remains debated, as previous data on outcomes are conflicting, and subgroup analyses are lacking. This study aimed to investigate the association between parenteral calcium administration and clinical outcomes in critically ill patients who had hypocalcemia with and without sepsis. Methods: This retrospective cohort study included individuals who developed hypocalcemia during the first 7 days of admission to a mixed medical-surgical adult ICU at a University-affiliated teaching hospital. Patients who were not receiving renal replacement therapy, and were admitted to the ICU for at least 48 h between October 1, 2015 and September 24, 2020, were included. The primary outcomes included all-cause 180-day mortality and time-to-shock resolution. Subgroup analyses were conducted in sepsis and nonsepsis patients with mild or moderate hypocalcemia, based on median splits. Proportional hazard regression analyses were performed to identify the association between parenteral calcium administration and outcome parameters. Results: Among the 1100 patients who met the inclusion criteria, 427 (38.8 %) patients were admitted for sepsis and 576 (52.4 %) patients received parenteral calcium. Patients who received and did not receive parenteral calcium demonstrated no significant difference in 180-day mortality (adjusted hazard ratio [aHR] = 1.18, 95 % confidence interval [CI]: 0.90 to 1.56). Intravenous calcium administration reduced the probability of a shorter time to shock resolution (adjusted odds ratio = 0.81, 95 % CI: 0.70 to 0.94). Subgroup analyses in patients with and without sepsis indicated no significant association between calcium administration (aHR = 1.63, 95 % CI: 0.99 to 2.69) and 180-day mortality (aHR = 1.06, 95  % CI: 0.74 to 1.51). Notably, parenteral calcium was associated with an elevated risk of 90- and 180-day mortality in patients who had sepsis and mild hypocalcemia (aHR = 1.88, 95 % CI: 1.02 to 3.47 and aHR = 1.79, 95 % CI: 1.07 to 3.00, respectively). Conclusions: Intravenous calcium administration did not provide survival or shock resolution benefits in ICU patients with hypocalcemia, and may even be harmful. Further research, including randomized controlled trials, are needed to confirm these findings.