The Utility of the Modified Frailty Index in Outcome Prediction for Elderly Patients with Acute Traumatic Subdural Hematoma

Abstract

This study aimed to evaluate the utility of the 11-variable modified Frailty Index (mFI) in prognosticating elderly patients with traumatic acute subdural haematomas (aSDH). A state-service Level 1 trauma centre registry was interrogated to investigate consecutive patients ≥65 years presenting with traumatic aSDH, with or without major extracranial injury, between January 2013 and December 2017. mFI on admission, demographics, admission details including Glasgow Coma Scale (GCS) and pupillary status and radiological findings were retrospectively retrieved from institutional records. Clinical outcome data was retrieved from medical records and the Victorian State Trauma Registry (VSTR). The outcome measures were (i) 30-day mortality; and (ii) 6-month unfavourable outcome, defined by the Extended Glasgow Outcome Scale (GOS-E). 529 consecutive cases were identified from the registry. Demographic data included: (i) age (median; IQR) = 80.46;74.17-85.89; (ii) mFI (mean±SD) = 1.96±1.42 of 11 variables. 416 cases (79%) had complete outcome data. As mFI increased from 0/11 variables to ≥5/11 variables (≥0.45), 30-day mortality risk increased from 17.72% to 39.29% (p=0.023) and 6-month unfavourable outcome risk increased from 40.51% to 96.43% (p<0.001). Multivariate analysis showed that greater mFI score of ≥3/11 variables (≥0.27) suggested a significantly higher risk of 30-day mortality (p=0.009) and unfavourable outcome (p<0.001). We conclude that increasing frailty, as measured by the mFI, was associated with significantly higher risk of 30-day mortality and 6-month unfavourable outcome in elderly patients presenting with aSDH to a Level 1 neurotrauma centre. Assessment of mFI in elderly patients with aSDH may be a useful determinant of outcome for this rapidly growing population.