QT interval prolongation and mortality in sepsis: a retrospective cohort study from the MIMIC-IV database

Sepsis is a leading cause of mortality in patients admitted to the intensive care unit (ICU), and QT prolongation (QTP) is common in critically ill patients. However, the association between QTP and long-term mortality in sepsis remains unexamined. This retrospective study included patients meeting the Sepsis-3 criteria upon ICU admission between 2008 and 2019, identified from the Intensive Care Medical Information Mart IV (MIMIC-IV) database. Patients were categorized into two groups based on the presence (QTP group) or absence (non-QTP group) of QTP. Clinical outcomes were compared between patients with and without QTP. We used Kaplan–Meier analysis to compare the 28-day and 1-year all-cause mortality between septic patients with and without QTP. Furthermore, we utilized multivariate regression, propensity score matching (PSM), inverse probability of treatment weighting (IPTW), and a survey-weighted generalized linear model to assess the association of QTP with 28-day and 1-year all-cause mortality in patients with sepsis. A total of 4,845 patients were enrolled, with 1,424 (29.4%) in the QTP group. Compared with the non-QTP patients, the QTP group had significantly higher 28-day mortality (19.17% vs. 13.15%, p < 0.001) and 1-year mortality (33.99% vs. 24.82%, p < 0.001). Following PSM, the QTP group exhibited significantly higher mortality at both 28-day mortality (18.81% vs. 15.51%, p < 0.05) and 1-year mortality (33.60% vs. 27.64%, p < 0.001) compared to the non-QTP group. Patients in the QTP group exhibited increased risk of both 28-day mortality (adjusted OR = 1.34, 95% CI: 1.11–1.61, p = 0.002) and 1-year mortality (adjusted OR = 1.40, 95% CI: 1.20–1.63, p < 0.001). The incidence of QTP was significantly elevated in ICU patients with sepsis compared with the general population and QTP was associated with increased risk-adjusted 28-day and 1-year mortality in ICU patients with sepsis.