Purpose: Many older patients with acute myocardial infarction (AMI) have impaired ability for activities of daily living (ADL). Impaired ADL leads to poor prognosis in elderly patients. The Global Registry of Acute Coronary Events (GRACE) score is widely used for risk stratification in AMI patients but does not consider physical performance, which is an important prognosis predictor for older adults. This study assessed whether the Barthel Index (BI) score combine the GRACE score would achieve improved one-year mortality prediction in older AMI patients.Patients and Methods: This single-center retrospective study included 688 AMI patients aged >= 65 years who were divided into an impaired ADL group (BI <= 60, n = 102) and a normal ADL group (BI >60, n = 586) based on BI scores at discharge. The participants were followed up for one year. Cox survival models were constructed for BI score, GRACE score, and BI score combined GRACE score for one-year mortality prediction.Results: Patients had a mean age of 76.29 +/- 7.42 years, and 399 were men (58%). A lower BI score was associated with more years of hypertension and diabetes, less revascularization, longer hospital stays, and higher one-year mortality after discharge. Multivariable Cox regression analysis identified BI as a significant risk factor for one-year mortality in older AMI patients (HR 0.977, 95% CI, 0.963-0.992, P = 0.002). BI (0.774, 95% CI: 0.731-0.818) and GRACE (0.758, 95% CI: 0.704-0.812) scores had similar predictive power, but their combination outperformed either score alone (0.810, 95% CI: 0.770-0.851).Conclusion: BI at discharge is a significant risk factor for one-year mortality in older AMI patients, which can be better predicted by the combination of BI and GRACE scores.