Worse cranial neurosurgical outcomes predicted by increasing frailty in patients with interhospital transfer status: Analysis of 47,736 patients from the National Surgical Quality Improvement Program (NSQIP) 2015–2019

Introduction: With limited healthcare resources and risks associated with unwarranted interhospital transfers (IHT), it is important to select patients most likely to have improved outcomes with IHT. The present study analyzed the effect of IHT and frailty on postoperative outcomes in a large database of patients who underwent cranial neurosurgical operations. Methods: The National Surgical Quality Improvement Program (NSQIP) database was queried for patients who underwent cranial neurosurgical procedures (2015–2019, N = 47,736). Baseline demographics, clinical characteristics, and outcome variables were compared between IHT and n-IHT patients. Univariate and multivariable analyses analyzed the effect of IHT status on postoperative outcomes and the utility of frailty (modified frailty index-5 [mFI-5] stratified into “pre-frail, “frail”, and “severely frail”) as a preoperative risk factor. Effect sizes from regression analyses were presented as odds ratio (OR) with associated 95% confidence intervals (95% CI). Results: Of 47,736 patients with cranial neurosurgical operations, 9612 (20.1%) were IHT. Patients with IHT were older, frailer, with a higher rate of functional dependence. In multivariable analysis adjusted for baseline covariates, IHT status was independent associated with 30-day mortality (OR: 2.0, 95% CI: 1.2–3.6), major complication (OR: 1.5, 95% CI: 1.1–2.1), extended hospital length of stay (eLOS) (OR: 3.8, 95% CI: 3.6–4.1), and non-routine discharge disposition (OR: 2.4, 95% CI: 1.8–3.2) (all p < 0.05). Within the IHT cohort, increasing frailty (“pre-frail”, “frail”, “severely frail”) was independently associated with increasing odds of 30-day mortality (OR: 1.4, 1.9, 3.9), major complication (OR: 1.4, 1.9, 3.3), unplanned readmission (OR: 1.1, 1.4, 2.1), reoperation (OR: 1.3, 1.5, 1.9), eLOS (OR: 1.2, 1.3, 1.5), and non-routine discharge (OR: 1.4, 1.9, 4.4) (all p < 0.05). All levels of frailty were more strongly associated with postoperative outcomes than chronological age. Conclusions: This novel analysis suggests that patients transferred for cranial neurosurgery operations are significantly more likely to have worse postoperative health outcomes. Furthermore, the analysis suggests that frailty (as measured by mFI-5) is a powerful independent predictor of outcomes in transferred cranial neurosurgery patients. The findings support the use of frailty scoring in the pre-transfer and preoperative setting for patient counseling and risk stratification.