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.

Study Design: Retrospective analysis of a prospectively maintained database.

Objectives: To evaluate the effects of interhospital transfer (IHT) status, age, and frailty on postoperative outcomes in patients who underwent spine surgery.

Methods: 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).

Results: 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.

Conclusions: 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.