Demographics and Outcomes of Interhospital Neurosurgical Transfer Patients Undergoing Spine Surgery.

Objective: Interhospital patient transfer (IHT) of patients is common and accounts for a significant portion of health care costs, yet the variables driving neurosurgical IHT have not been systematically described. We analyzed variables that distinguished spine surgery patients who underwent IHT from patients who did not undergo IHT to report on the effect of frailty on IHT.

Methods: A retrospective chart review was performed to collect data on consecutive patients undergoing spinal procedures during 2015-2017. IHT patients were identified and compared with non-interhospital patient transfer (n-IHT) patients to identify factors that distinguished the 2 patient groups using multivariate regression analysis. Studied variables included case complexity, frailty (modified frailty index), age, insurance status, and baseline demographic variables. Postoperative outcomes affected by transfer status were identified in binary regression analysis.

Results: During 2015-2017, there were 595 n-IHT and 76 IHT spine surgery patients (N = 671). Increased frailty (modified frailty index ≥3; odds ratio = 2.4, P = 0.01) and increased spine surgery complexity (spine surgery complexity score ≥2; odds ratio = 2.57, P = 0.002) were independent risk factors associated with IHT. IHT was an independent risk factor for increased hospital length of stay and increased postoperative complications (Clavien-Dindo scale; P < 0.001).

Conclusions: IHT patients comprise a more frail and surgically complex surgical spine population compared with n-IHT patients. IHT was also an independent risk factor for increased complications and length of stay after spine surgery. Patients' insurance status and age did not distinguish between IHT and n-IHT groups. This is the first report in any specialty to demonstrate increasing frailty is associated with IHT.