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.