The 5-Item Modified Frailty Index Aids in Predicting Risk of In-Hospital Complications Following Spine Trauma: A United States Nationwide Cohort Analysis of 356,583 Patients

Frailty has emerged as an important predictor of postoperative complications across surgical fields, but its role in traumatic spinal fractures remains underexplored. This study evaluated the relationship between frailty, measured with the 5-item Modified Frailty Index (mFI), and in-hospital complications in a national cohort of patients with spinal fracture. A retrospective cohort study was conducted using the National Trauma Databank from 2017 to 2021, identifying adult patients with spinal fractures. Patients were classified as nonfrail (NF, mFI = 0), mildly frail (MF, mFI = 0.2), and severely frail (SF, mFI ≥ 0.4) according to the 5-item mFI. Multivariable logistic regression analysis was performed to assess the association between frailty and complications during the primary hospitalization for spinal trauma while adjusting for key covariates, including Glasgow Coma Scale (GCS), Injury Severity Score (ISS), spine region, spinal cord injury, concomitant head injury, surgical intervention, and hospital characteristics. The final cohort included 356,583 patients. 53.0% were classified as NF, 25.5% as MF, and 21.5% as SF. SF patients had higher odds of developing complications compared with NF patients (OR = 1.86, 95% CI: 1.77–1.96, p < 0.001). Complications such as cardiac events (1.3%), thromboembolism (1.1%), and pressure ulcers (0.6%) were more prevalent in frail patients. Lower GCS scores (GCS 3–8: OR = 3.19, 95% CI: 3.03–3.36, p < 0.001) and higher ISS scores (ISS 16–24: OR = 5.27, 95% CI: 5.02–5.53, p < 0.001) were associated with increased complication risk. Additionally, surgical intervention (OR = 2.84, 95% CI: 2.73–2.94, p < 0.001), the presence of spinal cord injury (OR = 2.73, 95% CI: 2.60–2.87, p < 0.001), and head injury (OR = 1.57, 95% CI: 1.52–1.63, p < 0.001) increased the likelihood of complications. Alongside the GCS and ISS, the 5-item mFI is an effective tool for identifying patients who may be at increased risk of in-hospital complications following traumatic spinal fractures. These findings highlight the importance of frailty assessment in spine trauma management and optimized patient care.