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

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

The New Jersey STEMI “system”

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

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.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.

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

Methods Retrospective cohort analysisRetrospective cohort analysis Five years of data ( )Five years of data ( ) Pennsylvania Statewide Trauma RegistryPennsylvania Statewide Trauma Registry  32 accredited trauma centers  Admitting diagnosis of injury  Age >18

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

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

Methods - Power We calculated the detectable mortality difference given: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)

Methods - Analysis UnadjustedUnadjusted  Pearson’s chi-square, rank sum, T-test, Logistic regression AdjustedAdjusted  Logistic regression  Negative binomial regression (LOS)

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

Results - Power Night as compared to dayNight as compared to day  Powered to detect 0.63% mortality difference Weekend as compared to weekdayWeekend as compared to weekday  Powered to detect 0.53% mortality difference

Results – Demographics

Results - Demographics

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

Limitations Retrospective dataRetrospective data Single state analysisSingle state analysis Negative findings raise power concernsNegative findings raise power concerns Inadequate injury severity adjustmentInadequate injury severity adjustment Inadequate case mix adjustmentInadequate case mix adjustment Exclusion of transfer patientsExclusion of transfer patients

Conclusions Patients presenting at night are no more likely to die than patients presenting during the dayPatients 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 weekdaysPatients presenting on the weekend are less likely to die than patients presenting on weekdays

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

Acknowledgments Co-authorsCo-authors  Pat Reilly, MD  C. William Schwab, MD  Charles C. Branas, PhD  Juliet Geiger, RN MSN  Douglas J. Wiebe, PhD AHRQ K08HS017960AHRQ K08HS Pennsylvania Trauma System FoundationPennsylvania Trauma System Foundation

Questions?