Hospital Volume-Outcome Relationship in Severe Traumatic Brain Injury: A Nationwide Observational Study in Japan.

Abstract

The hospital volume-outcome relationship in patients with severe traumatic brain injury (TBI) remains unclear. This study investigated the association between the volume of patients with severe TBI and in-hospital mortality. This observational study identified patients with severe TBI (Glasgow Coma Scale score <9 and Abbreviated Injury Scale head score ≥3) from the Japan Trauma Databank (2010-2018). Hospitals were grouped on the basis of annual patient volume as follows: low-volume (4-19 patients/year); middle-volume (20-35 patients/year); and high-volume (36-51 patients/year) groups. The association between hospital volume categories and in-hospital mortality was examined using a multivariate mixed-effect logistic regression analysis. A subgroup analysis was performed based on the presence of severe extracranial injuries. A total of 11,344 patients from 64 hospitals were included. The median age of the patients was 57 years (interquartile range, 40-77), and 7933 (70.0%) patients were men. A total of 4879 (43.1%) patients died in the hospital. The medium-volume (adjusted odds ratio [OR], 0.76; 95% confidence interval [CI], 0.62-0.93) and high-volume (adjusted OR, 0.69; 95% CI, 0.52-0.94) groups were significantly associated with lower in-hospital mortality. The subgroup analysis revealed that the medium-volume (adjusted OR, 0.70; 95% CI, 0.54-0.92) and high-volume (adjusted OR, 0.64; 95% CI, 0.42-0.96) groups were significantly associated with lower in-hospital mortality for isolated TBI patients. Higher hospital volumes were significantly associated with lower in-hospital mortality after severe TBI. Regionalization and referral to higher-volume hospitals are beneficial for severe TBI patients.