Abstract 11515: Does Prolonged Dual Antiplatelet Therapy Increase Mortality After Drug-Eluting Stent Implantation?

Abstract

Introduction: The Dual Antiplatelet Therapy (DAPT) trial found a borderline increase in the rate of all-cause mortality in patients treated with 30 compared with 12 months of DAPT (2.0% vs. 1.5%, HR 1.36, 95% CI 1.00-1.85, P = 0.05). Hypothesis: A finding of borderline significance in a mega-trial may reflect the play of chance. Methods: We used a Bayesian conjugate-normal approach (Figure A) to update the mortality results from the DAPT trial with an empiric prior probability distribution based on results in 9 smaller randomized controlled trials (RCTs). Results: The empiric prior (blue), which suggests that the odds of mortality in the 9 smaller RCTs could be 6% lower or as much as 40% higher after prolonged than after short DAPT, overlaps with the likelihood (red) from the DAPT trial itself. Bayesian inference (black) affirms a significant increase in mortality with prolonged DAPT (posterior mean odds ratio [OR] 1.21, 95% Bayesian confidence interval [BCI] 1.02-1.44). Sensitivity analysis, which weighs the number of effective events by the proportion of patients with acute coronary syndromes, produces a nearly identical point estimate (OR 1.23, 95% BCI 0.96-1.58). Conclusions: Our analysis provides credible evidence that 30 months of DAPT is associated with higher mortality rates than is 12 months of therapy. The mortality increase in the DAPT trial is predictable from prior RCTs and not likely to be a chance finding.