Association between frailty and clinical outcomes in critically ill coronary artery disease patients: A retrospective cohort study.

ObjectiveFrailty is prevalent in cardiovascular disease but lacks objective assessment tools in critical care. This study evaluated the association between the Frailty Index based on laboratory data (FI-LAB) at ICU admission and clinical outcomes in critically ill patients with coronary artery disease (CAD).MethodsThis retrospective cohort study used data from the MIMIC-IV and MIMIC-III Carevue databases. Patients were stratified by FI-LAB into mild (<0.25), moderate (0.25-0.4), and severe (>0.4) frailty. Multivariable logistic regression assessed in-hospital mortality, Cox models evaluated 28-day and 1-year mortality, and Fine-Gray competing risk models examined malignant arrhythmia. Dose-response relationships and subgroup effects were also assessed.ResultsAfter full adjustment, severe frailty was associated with elevated in-hospital mortality (OR = 4.41, 95% CI: 2.60-7.48, P < 0.001), 28-day mortality (HR = 3.42, 95% CI: 2.17-5.40, P < 0.001), and 1-year mortality (HR = 3.60, 95% CI: 2.56-5.06, P < 0.001). Moderate frailty similarly conferred increased risks for 28-day (HR = 1.70, P = 0.026) and 1-year mortality (HR = 2.09, P < 0.001). The Fine-Gray model showed that severe frailty was associated with a higher subdistribution hazard of malignant arrhythmia (SHR = 2.68, 95% CI: 1.39-5.18, P = 0.003). A nonlinear relationship between FI-LAB and 1-year mortality was observed (P for nonlinearity = 0.042). Results were consistent in the MIMIC-III cohort.ConclusionsHigher FI-LAB scores at ICU admission were associated with increased risks of in-hospital mortality, 28-day mortality, 1-year mortality, and malignant arrhythmia. FI-LAB may serve as a useful prognostic tool for risk stratification in critically ill patients with CAD.