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

## TL;DR

This study shows that β-blockers significantly reduce mortality in critically ill patients with type 2 myocardial infarction.

## Contribution

The study provides novel evidence that β-blocker therapy reduces both short-term and long-term mortality in ICU patients with T2MI.

## Key findings

- β-blocker use was associated with a 45% reduction in in-hospital mortality.
- The therapy reduced 30-day mortality by 36% and 1-year mortality by 27%.
- Results were robust across sensitivity and subgroup analyses.

## Abstract

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.

To evaluate the impact of β-blockers on short-term and long-term mortality in intensive care unit (ICU) patients with T2MI.

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.

Before PSM, in-hospital, 30-day, and 1-year mortality rates were 13.3%, 17.2%, and 34.1%. Kaplan–Meier survival analysis demonstrated significantly higher survival probability in the β-blocker group (log-rank test, P < 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.

β-blockers significantly reduce mortality in critically ill T2MI patients, supporting their use as a key treatment strategy for this population.