DAPT Medication Nonadherence and Clinical Trial Results
- The trial compared the following regimens: abbreviated DAPT (1-month DAPT followed by single antiplatelet therapy [SAPT] for 11 months among patients not on OAC or SAPT+OAC for 5 months followed by OAC only among patients on OAC) vs. standard DAPT regimen (6-month DAPT followed by ASA among patients not on OAC or DAPT+OAC for 3 months followed by ASA+OAC among patients until 11 months followed by OAC only).
- After adjusting for nonadherence, there was no difference in the ischemic endpoint in the two groups regardless of OAC use.
- There was significantly less bleeding in the abbreviated DAPT group, and among OAC patients, SAPT discontinuation after 6 months was associated with lower rates of bleeding.
What is the impact of nonadherence to antiplatelet therapy after percutaneous coronary intervention (PCI) in clinical trials?
At 1 month after PCI, 4,579 high bleeding risk patients in the MASTER DAPT (Management of High Bleeding Risk Patients Post Bioresorbable Polymer Coated Stent Implantation With an Abbreviated Versus Prolonged DAPT Regimen) trial were randomized to single antiplatelet therapy (SAPT) for 11 months (or 5 months in patients on oral anticoagulation [OAC]) or dual antiplatelet therapy (DAPT) for >2 months followed by SAPT. Coprimary outcomes included net adverse clinical events (NACE), major adverse cardiac and cerebral events (MACE), and major or clinically relevant nonmajor bleeding (MCB) at 335 days. Inverse probability-of-censoring weights were used to correct for nonadherence Academic Research Consortium type 2 or 3.
In total, 464 (20.2%) patients in the abbreviated-treatment and 214 (9.4%) in the standard-treatment groups incurred nonadherence Academic Research Consortium type 2 or 3. At inverse probability-of-censoring weights analyses, NACE (hazard ratio [HR], 1.01; 95% confidence interval [CI], 0.88-1.27) or MACE (HR, 1.07; 95% CI, 0.83-1.40) did not differ, and MCB was lower with abbreviated compared with standard treatment (HR, 0.51; 95% CI, 0.60-0.73) consistently across OAC subgroups; among OAC patients, SAPT discontinuation 6 months after PCI was associated with similar MACE and lower MCB (HR, 0.47; 95% CI, 0.22-0.99) compared with SAPT continuation.
In the MASTER DAPT adherent population, 1-month compared with >3-month DAPT was associated with similar NACE or MACE and lower MCB. Among OAC patients, SAPT discontinuation after 6 months was associated with similar MACE and lower MCB than SAPT continuation.
The authors published the results of this prespecified per-protocol analysis of the MASTER DAPT trial evaluating abbreviated DAPT vs. standard DAPT therapy stratified further by OAC use after correcting for nonadherence. The trial compared the following regimens: abbreviated DAPT (1-month DAPT followed by SAPT for 11 months among patients not on OAC or SAPT+OAC for 5 months followed by OAC only among patients on OAC) vs. standard DAPT regimen (6-month DAPT followed by aspirin [ASA] among patients not on OAC or DAPT+OAC for 3 months followed by ASA+OAC among patients until 11 months followed by OAC only). They performed inverse probability-of-censoring weights to correct for nonadherence and results showed no difference in ischemic events between the two groups regardless of OAC use. More importantly, abbreviated DAPT regimen was associated with lower odds of major and nonmajor bleeding in the OAC and non-OAC population. Findings highlight the importance of appropriate correction for nonadherence in clinical trials to limit result bias, and suggest that SAPT discontinuation after 6 months is associated with lower bleeding among patients on OAC.
Keywords: Absorbable Implants, Anticoagulants, Aspirin, Drug-Eluting Stents, Hemorrhage, Medication Adherence, Myocardial Ischemia, Percutaneous Coronary Intervention, Platelet Aggregation Inhibitors, Polymers, Randomized Controlled Trials as Topic, Secondary Prevention
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