Abstract Background Previous studies have indicated that activities of daily living (ADL) can influence the prognosis of patients with acute myocardial infarction. The purpose of this study is to delineate the clinical characteristics, treatment regimens, and prognosis of patients with acute ST-segment elevation myocardial infarction (STEMI) who have impaired ADL. Methods The data for this study were derived from a Health and Medical Big Data Superplatform, comprising a retrospective cohort of patients admitted to and discharged from 72 secondary and tertiary hospitals from 2010 to 2023. The inclusion criteria encompassed patients with a discharge diagnosis of STEMI.ADL prior to STEMI was evaluated using the Barthel index(BI),a widely used assessment tool for evaluating ADL.The patients' BI were obtained from their resident health records.Patients were categorized into two groups: ADL normal group and ADL impaired group. A comparative analysis was conducted between the two groups regarding clinical characteristics, treatment regimens, and prognosis. Results This study included 24,906 STEMI patients with normal ADL and 1,002 STEMI patients with impaired ADL. Baseline data revealed that patients in the ADL impaired group had a higher proportion of females (43.0% vs. 37.8%, p=0.001), were older (74.0[64.0,81.0] vs. 69.0[65.0,75.0], p<0.001), and had a higher proportion of Killip III and above (24.30% vs. 14.10%, p<0.001). Additionally, the ADL impaired group had a higher prevalence of comorbidities. In terms of treatment, the ADL impaired group had lower proportions of patients undergoing percutaneous coronary intervention (PCI) (43.8% vs. 65.3%, p<0.001) and primary PCI (PPCI) (36.4% vs. 55.1%, p<0.001). Additionally, the ADL impaired group exhibited lower utilization rates of antiplatelet drugs, ACEI/ARB, beta-blockers, ARNI, and statins, but higher rates of diuretics and cardiac glycosides. Regarding prognosis, the ADL impaired group had a higher in-hospital mortality rate (5.69% vs. 2.89%, p<0.001). The median follow-up time was 1,220 days. In the ADL impaired group, the rates of all-cause mortality (52.0% vs. 24.7%, p<0.001), cardiovascular mortality (37.3% vs. 17.3%, p<0.001), recurrent non-fatal myocardial infarction (11.1% vs. 8.30%, p=0.002), and recurrent stroke (11.9% vs. 8.66%, p=0.001) were higher. However, the rate of revascularization was lower in the ADL impaired group (6.69% vs. 9.20%, p=0.008), and the risk of cerebral hemorrhage showed no significant difference (1.00% vs. 0.81%, p=0.631). In a multivariate Cox regression analysis adjusting for age, gender, Killip, medical history, and treatment strategies, impaired ADL remained an independent risk factor for increased all-cause mortality (aHR 1.309, 95% CI: 1.195-1.434, p<0.001). Conclusions Impairment of ADL is associated with adverse clinical outcomes in patients with STEMI.Baseline characteristics of patientsMedications of patients