Frailty predicts worse outcomes for spine surgery patients with interhospital transfer status: Analysis of 295,875 patients from the National Surgical Quality Improvement Program (NSQIP) 2015-2019

Retrospective analysis of a prospectively maintained database.To evaluate the effects of interhospital transfer (IHT) status, age, and frailty on postoperative outcomes in patients who underwent spine surgery.The National Surgical Quality Improvement Program (NSQIP) database was queried for patients who underwent spine surgeries from 2015 to 2019 (N = 295,875). Univariate and multivariable analyses were utilized to analyze the effect of IHT on postoperative outcomes and the contribution of baseline frailty status (mFI-5 score stratified into "pre-frail", "frail", and "severely frail") on outcomes in IHT patients. Effect sizes were summarized by odds ratio (OR) with associated 95% confidence intervals (95% CI).Of 295,875 patients in the study, 3.3% (N = 9666) were IHT status. On multivariable analysis, controlling for covariates, IHT status was significantly associated with greater likelihood of 30-day mortality (odds ratio [OR] = 9.3), major complications (OR=5.0), Clavien-Dindo (CD) grade IV complications (OR=7.0), unplanned readmission (OR=2.1), unplanned reoperation (OR=2.6), eLOS (OR=16.1), and discharge to non-home destination (OR=12.7) (all P 0.001). Increasing frailty was significantly associated with poor outcomes in spine surgery patients with IHT status compared to chronological age.This study provides evidence that IHT status is associated with poor outcomes in spine surgery patients. Furthermore, increasing frailty more than increasing age was a robust predictor of poor outcomes among IHT spine surgical patients. Baseline frailty status, as measured by the mFI-5, may be utilized for preoperative risk stratification of patients with IHT status with anticipated spine surgery.