In clinical practice, the impact of procedural or patient-related risk factors on 1-year clinical outcomes in patients receiving 1-month of dual antiplatelet therapy (DAPT) followed by P2Y12 inhibitor monotherapy after contemporary percutaneous coronary intervention (PCI) remains unclear. Using data from the multi-center REIWA registry which included patients treated with thin-strut biodegradable polymer drug-eluting stent (BP-DES) and 1-month DAPT followed by P2Y12 inhibitor monotherapy, we assessed the primary endpoint (a composite of cardiovascular death, myocardial infarction, definite stent thrombosis, ischemic or hemorrhagic stroke, and major or minor bleeding) in patients with and without procedural (treatment of three vessels, three or more lesions, three or more stents, bifurcation with two stents, long stenting, and target of chronic total occlusion) and patient-related risk factor (renal insufficiency, anemia, peripheral vascular disease, prior or current history of heart failure and advanced age of ≥ 75 years). Among the 1,202 patients who underwent complete revascularization by PCI, 276 (23.0%) had at least one procedural factor and 510 (42.4%) had one or more patient-related risks. At the 1-year follow-up, there were no statistical differences in the primary endpoint between patients with and without procedural risk factors. However, patients with patient-related risk factors, particularly those with renal insufficiency, anemia, heart failure, or advanced age, had a significantly higher incidence of the primary endpoint. In conclusion, patient-related risk factors significantly affected the 1-year clinical outcomes after BP-DES implantation and 1-month DAPT followed by P2Y12 inhibitor monotherapy, whereas procedural risk factors had little impact.