Meta-analysis of the efficacy of the DAPT score to decide on treatment duration
Meta-Analysis of Studies Examining the External Validity of the DAPT Score
Introduction and methods
The optimal duration of dual antiplatelet therapy (DAPT) in patients undergoing percutaneous coronary intervention (PCI) is an often debated issue. As DAPT is extended, a balance needs to be found between reducing ischemic events (such as stent thrombosis (ST) and myocardial infarction (MI)) on one side and increasing bleeding risk on the other side, while risk of mortality is unaffected . Current US and European practice guidelines strongly advise customization of DAPT duration according to the patient’s individual relative risk for ischemia vs. bleeding hazards [2,3]. The DAPT score has been developed for the evaluation of these competing risks and to aid clinicians in making a choice for DAPT duration .
Several studies have examined the external validity of the DAPT score, but results were inconsistent and showed no potential benefit from using the DAPT score decision tool [5-9]. However, most of these studies had a moderate sample size, thus, it is possible that negative results are due to low statistical power. This meta-analysis therefore set out to examine the external validity of the DAPT score and/or its decision tool.
Seven studies (total sample size 77,274 patients) were included in this meta-analysis [4-10]. The follow-up ranged from 9-24 months (median 18 months). The primary efficacy outcome was the composite of MI or ST, and the primary safety efficacy was bleeding events. The main analysis concerned the efficacy and safety outcomes of post PCI patients treated with extended (>12 up to 24 months) vs. standard (6-12 months) DAPT duration stratified by DAPT score stratum (DAPT score <2= low score stratum, DAPT score ≥2 = high score stratum).
- High DAPT score (≥2) was associated with increased risk for MI/ST (OR 1.54, 95%CI 1.41-1.69, P<0.01, I²=45%, 7 studies, n=77,274) and reduced risk for bleeding (OR 0.84, 95%CI 0.73-0.97, P=0.01 I²=0%, 7 studies, n=77272).
- In the high DAPT score stratum (≥2), extended as compared to standard DAPT duration was associated with lower risk for MI/ST (OR 0.67, 95% CI 0.48-0.94, P=0.02 I²=0%, 4 studies, n=6,173), and no increase in bleeding risk (OR 1.04, 95% CI 0.65-1.66, P=0.88 I²=0%, 4 studies, n=6,173).
- In the low DAPT score stratum (<2), extended DAPT duration was associated with no difference in risk for MI/ST (OR 1.04, 95% CI 0.76-1.43, P=0.80 I²=24%, 4 studies, n=9,948), and increased risk for bleeding (OR 1.58, 95% CI 1.15-2.15, P<0.01 I²=5%, 4 studies, n=9,948).
This meta-analysis of the efficacy and safety of extended vs standard DAPT in post PCI patients stratified by DAPT score strata, suggests that the DAPT score is useful for stratifying patients into risk strata for ischemic and bleeding events, and for the choice of DAPT duration. For patients with a high DAPT score, extended DAPT duration resulted in reduced ischemic risk with no increase in bleeding risk. For low DAPT score patients, extended therapy led to no difference in ischemic risk, but increased risk for bleeding.