Many injured patients presenting to level III/IV trauma centers will be transferred to level I/II centers, but how these transfers influence benchmarking at level III/IV centers has not been described. We hypothesized that the apparent observed to expected (O:E) mortality ratios at level III/IV centers are influenced by the location at which mortality is measured in transferred patients.
We conducted a retrospective study of adult patients presenting to Level III/IV trauma centers in Pennsylvania from 2008-2017. We used probabilistic matching to match patients transferred between centers. We used a risk-adjusted mortality model to estimate predicted mortality, which we compared to observed mortality at discharge from the level III/IV center (O1) or observed mortality at discharge from the level III/IV center for non-transferred patients and at discharge from the level I/II center for transferred patients (O2).
In total, 9,477 patients presented to 11 Level III/IV trauma centers over the study period (90% white, 49% female, 97% blunt mechanism, median ISS 8 IQR (4-10). Of these, 4,238 (44%) were transferred to Level I/II centers, of which 3,586 (85%) were able to be matched. Expected mortality in the overall cohort was 332 (3.8%). A total of 332 (3.8%) patients died, of which 177 (53%) died at the initial level III/IV centers (O1). Including post-transfer mortality for transferred patients in addition to observed mortality in non-transferred patients (O2) resulted in worse apparent O:E ratios for all centers and significant differences in O:E ratios for the overall cohort (O1:E: 0.53, 95% CI 0.45-0.61 vs. O2:E: 1.00, 95% CI 0.92-1.11, p<0.001).
Apparent O:E mortality ratios at level III/IV centers are influenced by the timing of measurement. To provide fair and accurate benchmarking and identify opportunities across the continuum of the trauma system, a system of shared attribution for outcomes of transferred patients should be devised.
Level 3: Retrospective cohort study
1Division of Traumatology, Surgical Critical Care and Emergency Surgery, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA
2Center for Clinical Epidemiology and Biostatistics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA
3Pennsylvania Trauma Systems Foundation, Harrisburg, PA
4Department of Emergency Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA
5Department of Emergency Medicine, Kimmel School of Medicine at the Thomas Jefferson University, Philadelphia, PA
Corresponding author and requests for reprint requests: Daniel Holena, MD MSCE, Department of Surgery, University of Pennsylvania School of Medicine, 51 N 39th St, MOB building 1st floor, Philadelphia PA 19104, Phone: 215-662-7323, email@example.com
Conflicts of Interest and Source of Funding: No authors have conflicts to declare. Portions of this work were supported by a training grant through the National Heart, Lung, and Blood Institute. (DNH; K08HL131995)
Meetings at which this work will be presented: 78th Annual Meeting of AAST and Clinical Congress of Acute Care Surgery in Dallas, Texas
Article Type: Clinical Science