Differences in patient characteristics, changes in treatment algorithms, and advances in device technology, together or separately, might limit the applicability of older randomized trials to contemporary clinical practice.
In this case, we look at patients and devices used in the contemporary clinical practice vs. those in the EXTEND DAPT. These differences were associated with attenuated benefits and great harm attributable to unnecessarily prolonged DAPT duration.
The EXTEND DAPT (Dual Antiplatelet Therapy) had concluded that prolonged DAPT reduced ischemic events at the expense of greater bleeding.
However, since the DAPT was release, new devices with very different instent thrombosis rates have changed the game completely. In other words, at present, the beneficial effect in bleeding is maintained, but ischemic risk has significantly dropped. In this regard, if the EXTEND DAPT were carried out today, its conclusions would be radically different.
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The study compared patient characteristics of those receiving contemporary DES between 2016 and 2017. After multiple adjustments, researchers estimated the effects of receiving 30-month DAPT vs. 12 months after DES stenting in the “real world”.
The randomized cohort receiving DES was 8,864 patients and the registry included 568,540 patients. Compared with the trial population, registry patients had more comorbidities and were more likely to present myocardial infarction and receive 2nd-generation drug-eluting stents.
A new analysis looked at the same data and found prolonged DAPT no longer reduced thrombosis (OR 0.40; CI 95%, 0.99% to 0.15%), combined cardiovascular and cerebrovascular events (OR 0.52; CI 95%, 2.62% to 1.03%) or MI (OR 0.52; CI 95%, 2.62% to 1.03%) significantly.
All of the above in the context of prolonged DAPT and a two-fold increased risk in bleeding (OR 2.42%; CI 95%, 0.79% to 3.91%).
Conclusion
The differences between patients and devices used in the contemporary clinical practice compared with those used in the DAPT trial were associated with attenuated benefits of prolonged DAPT and the same damage associated to bleeding.
These findings limit the applicability of older study outcomes to the contemporary clinical practice.
Original Title: Estimation of DAPT Study Treatment Effects in Contemporary Clinical Practice: Findings From the EXTEND-DAPT Study.
Reference: Neel M. Butala et al. Circulation. 2022 Jan 11;145(2):97-106. doi: 10.1161/CIRCULATIONAHA.121.056878.
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