Frailty Status and Outcomes in Patients with Acute Coronary Syndrome Undergoing Percutaneous Coronary Intervention: a multicentre retrospective cohort study.
AIM Frailty is increasingly recognised as an age-independent predictor of adverse outcomes in cardiovascular disease, yet it is rarely assessed in acute coronary syndrome (ACS) due to practical limitations. This study examined the prognostic significance of frailty, assessed using a laboratory-based frailty index (FI-Lab), in patients with ACS undergoing percutaneous coronary intervention (PCI). METHODS AND RESULTS We conducted a multicentre retrospective cohort study across five Korean hospitals using the Observational Medical Outcomes Partnership Common Data Model. Adult patients (≥18 years) who underwent PCI for ACS were included. Frailty status was determined as FI-Lab ≥ 0.4, calculated as the proportion of deficits across 28 routine laboratory variables, with inclusion restricted to patients having at least 70% of laboratory values available. Propensity score matching (1:1) and cox proportional hazards regression were employed to examine the relationships between frailty and clinical outcomes including recurrent acute myocardial infarction, hospital readmissions, and all-cause mortality. Of 5,405 patients, 25.2% were classified as frail. After matching, 929 pairs were analysed. Frailty was significantly associated with hospital readmission (HR 1.946; 95% CI 1.635-2.316) and all-cause mortality (HR 3.675; 95% CI 2.680-5.038), but not with recurrent AMI (HR 0.995; 95% CI 0.854-1.160). Subgroup analyses confirmed consistent associations across age and sex, with robust links to mortality in patients ≥65 years. CONCLUSION Frailty, as assessed by FI-Lab, independently predicted hospital readmission and mortality after PCI in patients with ACS. Automated, laboratory-based frailty screening is feasible in acute settings and supports its integration into cardiovascular nursing for early risk stratification and personalised care.