Benefit of switching dual antiplatelet therapy after ACS on dual antiplatelet therapy adherence: A prespecified analysis of the TOPIC randomized study

Abstract

The Timing Of Platelet Inhibition after acute Coronary Syndrome (TOPIC) trial showed that switching dual antiplatelet (DAPT) from aspirin plus a newer P2Y12 blocker (prasugrel or ticagrelor) to aspirin plus clopidogrel 1 month after an acute coronary syndrome (ACS) led to a reduction in bleeding complications with similar risk of ischemic recurrence. The objective of this prespecified analysis was to evaluate the impact of switching strategy on DAPT adherence. 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). Medical adherence to prescribed DAPT was assessed at 6 months and 1 year. Six hundred and forty-six patients were randomized and 645 analyzed, corresponding to 322 patients in the switched DAPT and 323 in the unchanged DAPT group. At 6 months and 1 year, the allocated DAPT regimen was significantly used more often in the switched group than in the unchanged DAPT group: 298 (92.5%) vs. 264 (81.7%) ( P < 0.01) at 6 months and 277 (87.7%) vs. and 242 (76.1%) ( P < 0.01) at 1 year. The reason for DAPT change was related to an adverse event in 66% of cases corresponding to an ischemic event in 17 patients (14.8%) and bleeding in 59 patients (51.3%) ( Fig. 1 ). In multivariable analysis, unchanged DAPT strategy and ischemic or bleeding events were significantly associated with non-adherence to prescribed DAPT ( Table 1 ). A switched DAPT was associated with significant improvement in the number of patients on prescribed DAPT at 6 months and 1 year following ACS. This improved adherence was related to reduction of side effects.