Impact of β-blockers on mortality in critically Ill patients with type 2 myocardial infarction: insights from a retrospective cohort study

Background: Type 2 myocardial infarction (T2MI) is common in critically ill patients, is associated with high mortality. However, the effect of β-blocker therapy on mortality remains uncertain. Objective: To evaluate the impact of β-blockers on short-term and long-term mortality in intensive care unit (ICU) patients with T2MI. Methods: This retrospective study analyzed 1,636 T2MI patients from the MIMIC-IV database. Propensity score matching (PSM) adjusted for confounders, resulting in 489 matched pairs. Mortality risks were analyzed using multivariable regression models, with subgroup and sensitivity analyses validating findings. Results: < 0.001). After propensity score matching to balance baseline characteristics, multivariable regression analysis demonstrated that β-blocker therapy was associated with a 45% reduction in in-hospital mortality [odds ratio (OR): 0.55, 95% confidence interval (CI): 0.38-0.82], a 36% reduction in 30-day mortality [hazard ratio (HR): 0.64, 95% CI: 0.48-0.84], and a 27% reduction in 1-year mortality (HR: 0.73, 95% CI: 0.61-0.88). Sensitivity analyses supported the robustness of these results. Conclusions: β-blockers significantly reduce mortality in critically ill T2MI patients, supporting their use as a key treatment strategy for this population.