Weekend & Night Outcomes in a Mature State Trauma System

1. Weekend & Night Outcomes in a Mature State Trauma System Brendan G. Carr, MD MS Department of Emergency Medicine Department of Biostatistics and Epidemiology University of Pennsylvania School of Medicine

2. Background • Outcomes for time-sensitive medical conditions are dependent upon the existence of comprehensive systems of care • Variability in outcomes has been demonstrated for a number of time-sensitive conditions including STEMI, cardiac arrest, and ischemic stroke

3. The New Jersey STEMI “system”

5. Background • Trauma Care in the US • Verification process • Demonstrated survival benefit • Explicit criteria required for: • Structures (staffing, OR availability) • Processes (QI program, prehospital notification)

6. Goals of the Investigation We sought to determine whether the probability of death or adverse clinical outcomes was higher among injured patients presenting at night or on the weekend.

7. Hypothesis We hypothesized that outcomes after trauma would be similar for patients presenting during nights or on the weekend.

8. Methods • Retrospective cohort analysis • Five years of data (2004-2008) • Pennsylvania Statewide Trauma Registry • 32 accredited trauma centers • Admitting diagnosis of injury • Age >18

9. Methods • Main Outcomes: • In-hospital mortality • Secondary Outcomes: • ICU length of stay • Hospital length of stay • Delay of more than two hours to laparotomy or craniotomy

10. Methods • Exposure: • Night presentation • 11pm – 6:59am • Weekend presentation • 11pm Friday – 6:59am Monday • Saturday 12:01 am – Sunday 11:59pm

11. Methods - Power • We calculated the detectable mortality difference given: • Known sample size • 2-tailed alpha of 0.05 • Power of 90% • Effect size estimate (mortality differences for night and weekend presentation based on pilot data)

12. Methods - Analysis • Unadjusted • Pearson’s chi-square, rank sum, T-test, Logistic regression • Adjusted • Logistic regression • Negative binomial regression (LOS)

13. Methods - Analysis • Case Mix adjustment • Modified Charlson • 15 instead of 19 comorbid conditions • Injury Severity adjustment • TRISS (Trauma – Injury Severity Score) • Anatomic injury scoring system (ISS) • Physiological scoring system (Revised Trauma Score)

14. Results - Power • Night as compared to day • Powered to detect 0.63% mortality difference • Weekend as compared to weekday • Powered to detect 0.53% mortality difference

15. Results – Demographics

16. Results - Demographics

17. Summary Results (Adjusted) Night Weekend Mortality Age < 55 Severe injury Blunt - Penetrating - Delay to laparotomy - Delay to craniotomy - ICU LOS - Hospital LOS • Mortality - • Age < 55 - • Severe injury - • Blunt - • Penetrating - • Delay to laparotomy + • Delay to craniotomy - • ICU LOS • Hospital LOS

18. Limitations Retrospective data Single state analysis Negative findings raise power concerns Inadequate injury severity adjustment Inadequate case mix adjustment Exclusion of transfer patients

19. Conclusions Patients presenting at night are no more likely to die than patients presenting during the day Patients presenting on the weekend are less likely to die than patients presenting on weekdays

20. Implications Explicit staffing and resource requirements for unplanned critical illness protect against the “weekend effect” The impact of similar systems based interventions should be tested for other time-sensitive conditions

21. Acknowledgments • Co-authors • Pat Reilly, MD • C. William Schwab, MD • Charles C. Branas, PhD • Juliet Geiger, RN MSN • Douglas J. Wiebe, PhD • AHRQ K08HS017960 • Pennsylvania Trauma System Foundation

22. Questions?