Impact of diabetes on benefit of switching dual antiplatelet therapy after acute coronary syndrome: A subanalysis of the TOPIC randomized study

Background The TOPIC trial showed that switching dual antiplatelet (DAPT) from aspirin plus a newer P2Y12 blocker (prasugrel or ticagrelor) to aspirin plus clopidogrel led to a reduction in bleeding complications with similar risk of ischemic recurrence. Purpose The objective of this analysis was to evaluate the impact of diabetes on the benefit of switched strategy. Methods TOPIC study randomized patients admitted for an ACS without adverse event at 1 month on aspirin and a newer P2Y12 blocker, to aspirin and clopidogrel (switched DAPT) or continuation of their drug regimen (unchanged DAPT). Results Three hundred and twenty-two patients were randomized to switched DAPT and 323 to unchanged DAPT. The primary endpoint of this analysis aimed to evaluate the impact of diabetes on clinical outcomes (composite of cardiovascular death, urgent revascularization, stroke and bleeding BARC classification ≥ 2) at 1 year. Hundred and seventy-seven patients were diabetics corresponding to 84 (26%) in the switched arm and 93 (29%) in the unchanged. No differences in primary outcome incidence was observed in the unchanged arm between diabetic and non-diabetic (25.8% vs. 26.5%, HR 95% CI 0.96 (0.60–1.54), P  = 0.88) while in the switched arm, primary endpoint occurred significantly more in diabetics (22.6% vs. 10.1%, 95% CI 2.72 (1.37–5.42), P P P  = 0.53). This lack of benefit in the diabetic arm was related to increased risk of recurrent ischemic events (HR 95% CI 1.52 (0.70–3.27), P  = 0.29) ( Fig. 1 ) despite reduction in bleedings BARC ≥ 2 (HR 0.37, P  = 0.04) ( Fig. 1 ). Conclusion Switching DAPT proved its benefit after ACS in terms of bleeding prevention. However, in diabetic patients switching DAPT was associated with excess of ischemic events despite bleeding prevention. Switching DAPT strategy should be preferred in non-diabetic patients.