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

This study aimed to evaluate the utility of the 11-variable modified Frailty Index (mFI) in prognosticating elderly patients with traumatic acute subdural hematomas (aSDHs). A state-service level 1 trauma center registry was interrogated to investigate consecutive patients >= 65 years of age presenting with traumatic aSDH, with or without major extracranial injury, between January 2013 and December 2017. mFI on admission, demographics, and admission details, including Glasgow Coma Scale (GCS) and pupillary status and radiological findings, were retrospectively retrieved from institutional records. Clinical outcome data were retrieved from medical records and the Victorian State Trauma Registry (VSTR). Outcome measures were 1) 30-day mortality and 2) 6-month unfavorable outcome, defined by the Extended Glasgow Outcome Scale (GOS-E). Five hundred twenty-nine consecutive cases were identified from the registry. Demographic data included: 1) age (median; interquartile range) = 80.46; 74.17-85.89; 2) mFI (mean +/- standard deviation) = 1.96 +/- 1.42 of 11 variables. Four hundred sixteen 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 unfavorable outcome risk increased from 40.51% to 96.43% (p < 0.001). Multi-variate 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 unfavorable 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 unfavorable outcome in elderly patients presenting with aSDH to a level 1 neurotrauma center. Assessment of mFI in elderly patients with aSDH may be a useful determinant of outcome for this rapidly growing population.