Risk-Score Guided Estimation of Absolute Benefit From Beta-blockers after Myocardial Infarction in Patients Without Heart Failure.
Abstract
Aims
To assess whether a modified clinical risk-score can stratify baseline risk and estimate expected absolute benefit from beta-blocker therapy in post-MI (myocardial infarction) patients with LVEF (left ventricular ejection fraction) ≥40%.
Methods
This substudy of the BETAMI-DANBLOCK trial included patients with a recent MI and LVEF ≥40% who were randomized to beta-blocker or no beta-blocker therapy. A modified Thrombolysis in Myocardial Infarction Risk Score for Secondary Prevention (TRS-2P) was constructed, and patients were categorized as low-, intermediate-, or high-risk. The primary outcome was a composite of all-cause mortality, new-MI, unplanned coronary revascularization, ischemic stroke, heart failure, or malignant ventricular arrhythmia. Treatment effects across TRS-2P strata were estimated using Cox proportional hazards and Fine-Gray subdistribution hazard models. Three-year absolute risk reduction (ARR) and number needed to treat (NNT) were calculated for each risk stratum.
Results
Among 5558 patients, 38.4% were classified as low-risk, 52.8% as intermediate-risk, and 8.8% as high-risk. Event rates increased stepwise with higher modified TRS-2P, with no evidence of heterogeneity in the relative treatment effects across risk-strata (hazard ratios: 0.88, 0.81 and 0.88, respectively). However, the score translated the modest relative effects into clinically distinct absolute benefits: Three-year ARR was 1.4% (NNT=72 [95% CI: 41 to 361]) in low-risk, 2.1% (NNT=47 [95% CI: 27 to 239]) in intermediate-risk, and 3.6% (NNT=28 [95% CI: 16 to 140]) in high-risk patients.
Conclusions
The modified TRS-2P stratified baseline risk and provided estimates of absolute beta-blocker benefit, supporting further evaluation of individualized, risk-guided treatment after MI in patients with LVEF ≥40%.