The Association of Calcium Derangements With 24-Hour Outcomes in the Deployed Combat Setting

Introduction: Calcium derangements remain poorly characterized in the combat trauma population. We describe the incidence of emergency department (ED) calcium derangements, associated physiologic derangements, and 24-hour mortality from the deployed combat setting. Materials and Methods: We analyzed adult casualties from 2007 to 2023 from the DoD Trauma Registry for U.S. military, U.S. contractor, and coalition casualties that had at least 1 ionized calcium value documented in the ED at a Role 2 or Role 3 military treatment facility. We constructed a series of multivariable logistic regression models to test for the association of hypocalcemia and hypercalcemia with physiological derangements, blood product consumption, and survival. Vital signs and other laboratory studies were based on the concurrent ED encounter. Results: There were 941 casualties that met inclusion for this analysis with 26% (245) having at least 1 calcium derangement. Among those, 22% (211) had at least 1 episode of hypocalcemia and 5% (43) had at least 1 episode of hypercalcemia in the ED. The vast majority (97%, 917) received calcium at least once. Median composite injury severity scores were lower among those with no calcium derangement (8 versus 17, P < .001). Survival was higher during the total hospitalization (98% versus 93%) among those with calcium derangements but similar at 24 hours (99% versus 98%, P = .059). After adjusting for confounder, any hypocalcemic measurement was associated with an elevated international normalized ratio (odds ratio 1.94, 95% CI 1.19-3.16), acidosis (1.66, 1.17-2.37), tachycardia (2.11, 1.42-3.15), hypotension (1.92, 1.09-3.38), depressed Glasgow coma scale (3.20, 2.13-4.81), elevated shock index (2.19, 1.45-3.31), submassive transfusion (3.97, 2.60-6.05), massive transfusion (4.22, 2.66-6.70), supermassive transfusion (3.65, 2.07-6.43), and all hospital stay mortality (2.30, 1.00-5.29). Comparatively, any hypercalcemic measurement was associated with acidosis (2.96, 1.39-6.32), depressed Glasgow coma scale (4.28, 1.81-10.13), submassive transfusion (3.40, 1.37-8.43), massive transfusion (6.25, 2.63-14.83), and supermassive transfusion (13.00, 5.47-30.85). Conclusions: Both hypocalcemia and hypercalcemia in the ED were associated with physiological derangements and blood product use, with a greater extent observed in those with hypocalcemia compared to those with hypercalcemia. Prospective studies are underway to better explain and validate these findings.