Association of Frailty with Adverse Outcomes in Patients with Critical Acute Myocardial Infarction: A Retrospective Cohort Study

Background: Frailty is a risk factor for acute myocardial infarction (AMI). This study examined the association between the modified frailty index (MFI) and adverse outcomes in patients with critical AMI.Methods: Data were obtained from the Medical Information Mart for Intensive Care IV database. Logistic and Cox regression models and a competing risk model were applied.Results: Of 5003 patients, 1496 were non-frail and 3507 were frail. Frailty was significantly associated with in-hospital mortality (per point, OR 1.13, 95% CI: 1.05-1.21; frail vs non-frail, OR 1.31, 95% CI: 1.04-1.65) and 1-year mortality (per point, HR 1.15, 95% CI: 1.11-1.20; frail vs non-frail, HR 1.37, 95% CI: 1.20-1.58). Frailty was significantly associated with post-discharge care needs (per point, OR 1.23, 95% CI: 1.14-1.33; frail vs non-frail, OR 1.47, 95% CI: 1.22-1.78). In the competing risk models, frailty was significantly associated with a lower probability of being discharged from the ICU (per point, HR 0.87, 95% CI: 0.85-0.90; frail vs non-frail, HR 0.73, 95% CI: 0.68-0.79) and hospital (per point, HR 0.82, 95% CI: 0.80-0.85; frail vs non-frail, HR 0.62, 95% CI: 0.57-0.68). Subgroup analyses showed the association of frailty with in-hospital and 1-year mortality was stronger in patients with a SOFA score <= 2 than in those with a SOFA score >2 (both p<0.05 for interaction).Conclusion: Frailty assessed by the MFI was an independent predictor of adverse outcomes in patients with critical AMI and may be helpful for prognostic risk stratification.