Hypocalcemia associated with adverse outcomes following severe traumatic injury in the Western Cape of South Africa: a secondary analysis of multicenter data from the Epidemiology and Outcomes of Prolonged Trauma Care (EpiC) study.

Background: Hypocalcemia precipitated by severe traumatic injury is well-described in the literature and has been associated with numerous adverse outcomes including mortality, transfusion requirement, and coagulopathy severity. The majority of studies to-date have been conducted in well-resourced clinical practice settings. Here, we describe adverse outcomes associated with severe hypocalcemia among a cohort of individuals presenting to emergency care following acute traumatic injury in a resource-limited setting.

Methods: The present study is a secondary analysis of the Epidemiology and Outcomes of Prolonged Trauma Care (EpiC) study, a prospective observational multicenter study of adult trauma patients in the Western Cape of South Africa. Individuals for whom a serum calcium level was measured at the time of hospital arrival were included, and the incidence of various adverse outcomes, including 30-day mortality, length of hospital stay, need for ICU admission, severity of organ dysfunction (defined by Sequential Organ Failure Assessment (SOFA) score), and blood transfusion requirement were compared across calcium strata. In total, 1989 individuals met criteria for inclusion.

Results: The incidence of any hypocalcemia (ionized calcium < 1.15 mmol/L) was 52%, while the incidence of severe hypocalcemia (< 1.00 mmol/L) was 5%. Adverse outcomes including 30-day mortality (4.0% vs. 2.9%), need for ICU admission (17% vs. 5.9%), maximum total SOFA score within 7 days (4 vs. 2), and need for blood product transfusion (35% vs. 18%), were all significantly more common in the severe hypocalcemia group as compared with others (p < 0.001 for all). Although hypercalcemia was uncommon (n = 21), there was a disproportionally high incidence of 30-day mortality in this population as compared with normocalcemic controls (19% vs. 2.6%, p < 0.001).

Conclusion: Severe hypocalcemia following trauma is associated with an increased risk of adverse outcomes including mortality, severe organ dysfunction, and need for ICU admission. It remains unclear whether hypocalcemia is a mediator of adverse events or simply a marker of illness severity. Furthermore, given the significantly increased risk of mortality observed in the hypercalcemia group, the role for calcium supplementation in the prevention of adverse outcomes in this population remains similarly unknown.