Operative trauma volume is not related to risk-adjusted mortality rates among Pennsylvania trauma centers

BACKGROUND Higher center-level operative volume is associated with lower mortality after complex elective surgeries, but this relationship has not been robustly demonstrated for operative trauma. We hypothesized that trauma centers in Pennsylvania with higher operative trauma volumes would have lower risk-adjusted mortality rates than lower volume institutions. METHODS We queried the Pennsylvania Trauma Outcomes Study database (2017-2019) for injured patients 18 years or older at Level I and II trauma centers who underwent an International Classification of Diseases, Tenth Revision (ICD-10), procedure code-defined operative procedure within 6 hours of admission. The primary exposure was tertile of center-level operative volume. The primary outcome of interest was inpatient mortality. We entered factors associated with mortality in univariate analysis (age, injury severity, mechanism, physiology) into multivariable logistic regression models with tertiles of volume accounting for center-level clustering. We conducted secondary analyses varying the form of the association between the volume and mortality to including dichotomous and fractional polynomial models. RESULTS We identified 3,650 patients at 29 centers meeting the inclusion criteria. Overall mortality was 15.9% (center-level range, 6.7-34.2%). Operative procedure types were cardiopulmonary (7.3%), vascular (20.1%), abdominopelvic (24.3%), and multiple (48.3%). The mean annual operative volume over the 3 years of data was 10 to 21 operations for low-volume centers, 22 to 47 for medium-volume centers, and 47 to 158 for high-volume centers. After controlling for patient demographics, physiology, and injury characteristics, there was no significant difference in mortality between highest and lowest tertile centers (odds ratio, 0.92; confidence interval, 0.57-1.49). Secondary analyses similarly demonstrated no relationship between center operative volume and mortality in key procedure subgroups. CONCLUSION In a mature trauma system, we found no association between center-level operative volume and mortality for patients who required early operative intervention for trauma. Efforts to standardize the care of seriously injured patients in Pennsylvania may ensure that even lower-volume centers are prepared to generate satisfactory outcomes. LEVEL OF EVIDENCE Prognostic and Epidemiological; Level III.