Assessment of Frailty in Predicting Surgical Outcomes in Patients with Chronic Subdural Hematomas: Retrospective Chart Review

BACKGROUND: The aim of this study is to determine if frailty, defined as modified frailty index (MFI) >2.7, correlated with worse postoperative outcomes in patients with chronic subdural hematomas (CSDHs). We also compare the predictive ability of the MFI with another widely used frailty measure, the Clinical Frailty Scale (CFS). METHODS: We conducted a retrospective chart review of elderly patients (≥65 years) who underwent a twist-drill craniostomy for the evacuation of CSDH at Hamilton General Hospital, Canada, between 2016 and 2018. The primary outcome was the modified Rankin Scale scores at discharge. Logistic regression analyses and receiver operating characteristic curves were carried out to further analyze the factors that influenced independence and functional improvement at discharge. RESULTS: Frail patients were significantly more dependent at discharge (P < 0.0001) and had a lower rate of functional improvement (P = 0.003). When compared with frailty measured by the MFI, frailty as measured by the CFS had a stronger association with functional independence (odds ratio [OR]: 0.081 [0.031, 0.211] vs. OR: 0.256 [0.124, 0.529]) and functional improvement (OR: 0.272 [0.106, 0.693] vs. OR: 0.406 [0.185,0.889]) on logistic regression analyses. Area under the receiver operating characteristic curve analyses showed that the inclusion of frailty into our predictive models improved accuracy. CONCLUSIONS: Elderly patients presenting with CSDH who are frail (MFI >0.27) have significantly worse functional outcomes following twist-drill craniostomies. Therefore assessing frailty in this population is important before managing these patients, and for this purpose the CFS is a superior predictor of postoperative function than the MFI.