Association Between Beta-Blocker Use and Outcomes in Patients with Sepsis-Induced Myocardial Injury: An Analysis Based on MIMIC-IV and eICU Databases

BACKGROUND: Sepsis-induced myocardial injury (SIMI) is a severe complication with high mortality. Beta-blocker therapy in SIMI remains controversial, lacking large-sample evidence. OBJECTIVES: To evaluate beta-blocker impact on mortality in SIMI patients using Medical Information Mart for Intensive Care IV (MIMIC-IV) and emergency intensive care unit (eICU) databases. METHODS: A retrospective cohort study based on MIMIC-IV (2008-2022) and eICU (2014-2015) databases included adult SIMI patients meeting Sepsis-3.0 criteria with elevated cardiac troponin. The primary exposure was beta-blocker use during ICU stay, and the primary outcome was in-hospital all-cause mortality. 1:1 propensity score matching was used to balance baseline characteristics, with multiple sensitivity analyses to verify result robustness. RESULTS: MIMIC-IV included 2368 SIMI patients (1338 using beta-blockers); eICU included 3805 patients (1030 using beta-blockers). After propensity score matching (MIMIC-IV: 837/group; eICU: 902/group), beta-blocker use was associated with a significant reduction in-hospital mortality (MIMIC-IV: 19.7% vs 29.9%, OR = 0.75, 95% CI: 0.60-0.94; eICU: 28.6% vs 35.1%, OR = 0.70, 95% CI: 0.56-0.88). Long-term mortality was lower by 39% (28-day), 33% (90-day), and 27% (1-year) (all P < 0.001). Multiple sensitivity analyses confirmed robustness (E-value: 2.00-2.21). Severely ill patients (Sequential Organ Failure Assessment ≥8) had the greatest mortality reduction associated with beta-blocker use (55%). Prolonged hospital stay was consistent with a survival benefit rather than adverse effects. CONCLUSION: Beta-blocker use is associated with reduced mortality and better long-term survival in SIMI patients, requiring prospective validation.