Association between corrected serum calcium levels and 28-day mortality in patients with sepsis: A cohort study

Abnormally corrected serum calcium (sCa) levels are associated with poor outcomes in various diseases, yet their relationship with short-term mortality in sepsis patients remains underexplored. This study investigates the association between corrected sCa levels and 28-day mortality in sepsis patients. We analyzed data from 7627 sepsis patients in the electronic intensive care unit Collaborative Research Database, categorizing them into 4 groups based on corrected sCa levels. Multivariate logistic regression, subgroup analysis, restricted cubic splines, and segmented regression models assessed the relationship between corrected calcium levels and mortality. Kaplan-Meier curves compared survival probabilities across groups. The 28-day mortality rate was 15.94%. After adjusting for confounders, patients in the highest corrected sCa group (>10.5 mg/dL) exhibited a significantly increased mortality risk (hazard ratio [HR]: 1.642, 95% confidence interval: 1.278-2.109) compared to the reference group (8.5-9.5 mg/dL). A U-shaped relationship was noted, with an inflection point at 9.08 mg/dL. Below this point, each 1.0 mg/dL increase in corrected sCa reduced mortality risk by 7.0% (HR, 0.930). Above 9.08 mg/dL, each 1.0 mg/dL increase raised mortality risk by 21.3% (HR, 1.213). Both low and high corrected sCa levels are linked to increased 28-day mortality in sepsis patients, highlighting the importance of monitoring calcium levels in this population.