One month of dual antiplatelet therapy (DAPT) did not reach noninferiority compared with three months of DAPT for net adverse clinical events (NACE) in East Asian patients with high bleeding risk (HBR) following PCI with a drug-eluting stent (DES), according to results from the HOST-BR trial published Oct. 23 in The Lancet. Furthermore, three months of DAPT was noninferior to 12 months of DAPT for net adverse clinical events and major adverse cardiac or cerebral events (MACCE), and it was superior for bleeding in patients without HBR.

"Evidence on the duration of DAPT according to bleeding risk is scarce," write study authors Jeehoon Kang, MD, et al. To address this gap, the open-label HOST-BR clinical trial, conducted across 50 centers in South Korea, stratified 4,897 patients undergoing PCI with DES as either HBR (n=1,598; median age 76 years; 34% women) or non-HBR (n=3,299; median age 64 years; 21% women). Those in the HBR arm were subsequently randomized 1:1 to either one-month (n=798) or three-month DAPT (n=800), while those in the non-HBR arm were randomized 1:1 to either three-month (n=1,649) or 12-month DAPT (n=1,650).

Results at one year in the HBR arm showed that one-month DAPT did not reach noninferiority for NACE, defined as all-cause death, myocardial infarction [MI], stent thrombosis, stroke or major bleeding, which occurred in 19% of patients compared with 14% of those receiving three-month DAPT (hazard ratio [HR], 1.337; p=0.82 for noninferiority). MACCE (including cardiovascular death, MI, definite or probable stent thrombosis or ischemic stroke) occurred in 10% vs. 6% of patients and actionable nonsurgical bleeding in 14% vs. 16%, respectively.

Among patients in the non-HBR arm, 3% who received three-month DAPT vs. 5% who received 12-month DAPT experienced NACE (HR, 0.657; p<0.0001 for noninferiority); 2.2% vs. 2.3% experienced MACCE (HR, 0.984; p=0.0082 for noninferiority) and 8% vs. 12% experienced bleeding (HR, 0.631; p<0.0001).

Within the HBR arm, "The higher incidence of adverse events with one-month DAPT was potentially driven by a higher risk of thrombotic events, which can be inferred from the increased risk of cardiovascular death, and ischemic stroke," Kang, et al., write. "The increased risk of cardiovascular death could be explained by the natural healing process after stent implantation...A premature discontinuation of DAPT before full endothelial coverage could lead to thrombotic events."