Association between the Clinical Frailty Scale and Neurological Outcomes in Out-of-Hospital Cardiac Arrest: A Retrospective Study

Background: Frailty is a physical condition characterized by increased vulnerability to external stressors. This study investigated the impact of premorbid frailty, as measured by the Clinical Frailty Scale (CFS), on neurological prognosis in patients with out-of-hospital cardiac arrest (OHCA). Methods: This is a single-center retrospective study. Data from 2006 to 2020 were analyzed for 595 adult OHCA patients admitted to the intensive care unit of National Taiwan University Hospital following resuscitation. Variables included demographics, medical history, resuscitation details, post-resuscitation data, and frailty assessments based on CFS. The primary outcome was favorable neurological performance, defined as a cerebral performance category (CPC) score of 2 or less at discharge. Results: In total, 523 of the 595 patients were included in the analysis. Among these, 224 survived, and 173 exhibited favorable neurological outcomes. Patients with favorable outcomes had significantly lower CFS scores than those with poor outcomes (3.2 +/- 1.5 vs. 4.5 +/- 1.8, p < 0.0001). The proportion of favorable neurological outcomes declined as CFS scores increased. Multivariate logistic regression analysis identified several factors independently associated with worse neurological outcomes: CFS >4 (odds ratio (OR): 0.301, 95% confidence interval (CI): 0.163-0.540), age >70 years (OR: 0.969, 95% CI: 0.953-0.986), history of malignancy (OR: 0.421, 95% CI: 0.209-0.813), epinephrine >2 mg during resuscitation (OR: 0.776, 95% CI: 0.712-0.840), and arterial blood gas pH <7.1 (OR: 28.396, 95% CI: 6.487-129.350). The model demonstrated good performance, with an area under the curve (AUC) value of 0.853. No significant relationships were observed between CFS and other variables. Conclusions: CFS values <= 4 were independently associated with favorable neurological outcomes following OHCA.