Skip to Main Content

Study Summary

The performance of the DAPT score — a clinical decision tool aimed to balance ischemic and bleeding risk and identify patients who would benefit from another 18 months of dual antiplatelet therapy (DAPT) following completion of an initial 12 months of DAPT —was evaluated in a nationwide real-world population. A total of 41,101 participants in Sweden (SWEDEHEART registry) who were event-free on DAPT for 12 months were followed up for 30 months. When stratified by DAPT score, the discrimination of risk was 0.58 (95% confidence interval [CI]: 0.56 to 0.60) for myocardial infarction or stent thrombosis; 0.54 (95% CI: 0.53 to 0.55) for major adverse cardiovascular and cerebrovascular events (MACCE; myocardial infarction, stroke, and all-cause death), and 0.49 (95% CI: 0.45 to 0.53) for fatal or major bleeding (see accompanying Hurst’s Central Illustration). The calibration, which measures the ability of a model to predict absolute risk, was shown to follow a U-shaped pattern for MACCE, with patients with low DAPT score having intermediate risk of MACCE and those with intermediate DAPT scores having a low risk. The thrombotic and bleeding events differed from the DAPT trial from which the score was initially derived in that the rates of fatal or major bleeding were similar between high risk and low risk groups (cumulative incidence 0.7% vs. 0.8%; HR: 0.88; 95% CI: 0.69 to 1.12) and lower than the rates in the DAPT study (thienopyridine arm 2.5% vs. placebo 1.6%; HR 1.61 [95% CI, 1.21 to 2.16]; P = 0.001).

Commentary

Study Strength: The large, unselected, and real-world population enabled assessment of the DAPT score in a contemporary setting. Advanced statistical modeling was used.

Study Limitations: It is important to note the differences in methodologies used in the original DAPT trial and the SWEDEHEART registry. First, the original DAPT trial included patients who had received first-generation drug-eluting stents and excluded patients who had received stents with diameters <2.25 mm or >4.0 mm. Second, in addition to aspirin, 65.2% of patients in the original DAPT trial received clopidogrel and 34.8% received prasugrel, compared with the21.6% vs 20.7% who received ticagrelor, 76.1% vs. 75.5% who received clopidogrel and 2.3% vs. 3.8% who received prasugrel in the low (<2) and high (≥2) DAPT score subgroups, respectively, in the real-world trial. Lastly, definitions of bleeding differed between the two trials. The DAPT score used the GUSTO criteria for bleeding while the real-world trial used a composite outcome of fatal bleeding and nonfatal major bleeding.

Next Steps/Clinical Perspective: The SWEDEHEART trial proved the importance of clinical judgment in guiding treatment. This study demonstrated that the DAPT score is a statistical model of uncertain utility.

Trial Reference

+
Ueda  P, Jernberg  T, James  S, et al. External validation of the DAPT score in a nationwide population. J. Am. Coll. Cardiol. doi:10.1016/j.jacc.2018.06.023

Pop-up div Successfully Displayed

This div only appears when the trigger link is hovered over. Otherwise it is hidden from view.

>