Adverse events in acute myocardial infarction patients: the DAPT Score for risk stratification in an Asian population
Authors: Nakada S , Lee A , Huang W , Yeo K K ,   SingCLOUD Governance Committee
Published: October 2021

Abstract

Background
Dual antiplatelet therapy (DAPT) is essential in mitigating adverse ischemic events after myocardial infarction (MI), and current guidelines have recommended the therapy to be administered for at least 1 year. Though prolonged DAPT helps to reduce ischemic events in high-risk patients, it can also increase the risk of significant bleeding. Risk stratification tools, such as the DAPT Score, can help to identify patients who are most or least likely to benefit from prolonged DAPT.

Purpose
To evaluate the performance of the DAPT Score as a predictor of major adverse cardiovascular events (MACE) in an Asian cohort who underwent percutaneous coronary intervention (PCI) for MI.

Methods
The analysis cohort consisted of 2086 MI patients (86% of primary PCI patients) who were admitted to Singaporean hospitals between 2012 and 2014. Demographic, clinical and therapeutic data regarding the index hospitalisation and 12-month follow-up period were collected. Patients were grouped according to their DAPT Score (high ischemic vs high bleeding risk) and DAPT duration (12 vs &lt;12 months; Figure 1). The primary endpoint was MACE (all-cause mortality, recurrent MI and stroke). MACE as an outcome was evaluated using multivariable Cox regression adjusted for age, gender, ethnicity, smoking status, prior MI, PCI or coronary artery bypass graft, hypertension, dyslipidaemia, cerebrovascular disease, diabetes mellitus, family history of coronary artery disease, vein graft stent and type of MI at presentation.

Results
The overall incidence rate of MACE in this cohort was 12.3%. There was a significantly higher MACE rate in Group 2 patients compared to Group 1 patients (high ischemic risk and &lt;12-month DAPT vs high ischemic risk and 12-month DAPT; hazard ratio: 1.37, 95% confidence interval: 1.02–1.83, P=0.038). No other significant differences in MACE rates were observed among the rest of the groups (Group 3: 1.44 [0.89–2.34]; Group 4: 1.15 [0.61–2.16], P&gt;0.050). Furthermore, MACE was independently associated with diabetes, hypertension, prior MI and cerebrovascular disease (1.49 [1.10–2.02], 1.43 [1.00–2.05], 1.41 [1.01–1.98], 3.06 [2.15–4.37], respectively, P&lt;0.050). Patients &lt;65 years and males were found to be protected against MACE (0.71 [0.51–0.99], 0.72 [0.52–0.99], respectively, P&lt;0.050). The overall bleeding rate was 2.2% (Group 1: 2.0%; Group 2: 1.7%; Group 3: 6.0%; Group 4: 0.7%).

Conclusions
The DAPT Score predicted MACE up to 12 months after PCI in MI patients with high ischemic risk and &lt;12 months of DAPT. This highlights the importance of adequate duration of DAPT in high ischemic risk MI patients. Moreover, the elderly, female, diabetic, hypertensive and those with prior cerebrovascular disease or MI were at increased risk for MACE.

Funding Acknowledgement
Type of funding sources: Public grant(s) – National budget only. Main funding source(s): National Medical Research Council - Health Services Research Grants (Ministry of Health, Singapore) CohortsCox regression for MACE