One-year clinical outcomes of aspirin versus indobufen in patients with NSTEMI: a multicenter retrospective cohort study

Background Aspirin is the cornerstone of antiplatelet therapy for non-ST-elevation myocardial infarction (NSTEMI), while indobufen serves as an alternative for patients with aspirin intolerance. However, comparative data on their long-term efficacy and safety in real-world NSTEMI populations are limited. Purpose This study aimed to compare the 1-year clinical outcomes of aspirin versus indobufen in a large real-world cohort of NSTEMI patients. Methods We conducted a multicenter retrospective cohort study including 68,514 NSTEMI patients from 82 hospitals in China (2010–2024). Propensity score matching (PSM) was performed to adjust for baseline imbalances, including age, sex, Killip's class, and comorbidities. Cox proportional hazards models were used to estimate adjusted hazard ratios (aHRs) for clinical endpoints. The primary endpoint was major adverse cardio-cerebrovascular events (MACCE) at 1 year. Secondary endpoints included net adverse clinical events (NACE) and gastrointestinal bleeding. Results Among 68,514 included patients, 67,496 received aspirin and 1,018 received indobufen. Prior to matching, the indobufen group was significantly older (mean age 72.50 vs. 64.87 years) and had higher prevalences of prior cerebral infarction (45.2% vs. 24.4%), diabetes (44.5% vs. 30.2%), and hypertension (75.3% vs. 51.6%) (all P < 0.001). After PSM, 1,012 matched pairs were formed. Aspirin was associated with a significantly lower risk of all-cause death compared to indobufen (aHR 0.751, 95% CI 0.587–0.961, P=0.023). No significant differences were observed for MACCE (aHR 1.101, P=0.286) or NACE (aHR 1.065, P=0.483). Notably, aspirin demonstrated a significantly lower risk of gastrointestinal bleeding (aHR 0.412, 95% CI 0.328–0.518, P<0.001). Subgroup analyses revealed that the survival benefit of aspirin was more pronounced in males, patients aged ≥65 years, those with hypertension, and those treated with clopidogrel (P for interaction = 0.083). Conclusions In this real-world NSTEMI population, aspirin was associated with superior 1-year survival and a more favorable bleeding safety profile compared with indobufen. The survival advantage of aspirin appears particularly evident when used in combination with clopidogrel.