Adherence to guideline-directed medical therapy and 3-year clinical outcome following acute myocardial infarction

Aims: Despite the well-established clinical benefits and strong recommendations in clinical guidelines, adherence to guideline-directed medical therapy (GDMT) is known to be insufficient. We investigated the adherence to GDMT and its impact on the 3-year clinical outcomes in patients with acute myocardial infarction (AMI). Methods and results: Source data were obtained from KAMIR-NIH, a Korean multi-centre observational registry. GDMT was defined according to the ACC/AHA Class I recommendations. Adherence to GDMT was assessed at discharge and every year thereafter. The differences in clinical characteristics between patients receiving and those not receiving GDMT were adjusted using propensity score matching (PSM) or inverse probability of treatment weighting (IPTW). The primary endpoint was major adverse cardiovascular events (MACE), which was a composite of all-cause death and non-fatal MACE, including myocardial infarction (MI), revascularization, or stroke. Of 12 815 patients, GDMT adherence was 70.2% at discharge, and decreased gradually into 54.6% at 3-year. GDMT at discharge was associated with lower MACE risk in the unadjusted analysis [hazard ratio (HR) = 0.51, 95% confidence intervals (CI) = 0.47-0.55, P < 0.001] and also in the PSM- or IPTW-adjusted analyses (HR = 0.77, 95% CI = 0.69-0.86; HR = 0.79, 95% CI = 0.72-0.86; P < 0.001, all). These findings were replicated in the 1-year or 2-year landmark analyses (HR = 0.58 to 0.82, P < 0.01, all). Conclusion: Adherence to GDMT was sub-optimal among patients with AMI in Korea. As the adherence to GDMT was associated with a lower incidence of MACE during 3-year follow-up, the maintenance of long-term GDMT might be crucial for patients with AMI.