Mortality benefit of transfer to level I versus level II trauma centers for head-injured patients.
OBJECTIVE
To determine whether head-injured patients transferred to level I trauma centers have reduced mortality relative to transfers to level II trauma centers.


METHODS
Retrospective cohort study of 542 patients with head injury who initially presented to 1 of 31 rural trauma centers in Oregon and Washington, and were transferred from the emergency department to 1 of 15 level I or level II trauma centers, between 1991 and 1994.


METHODS
A bivariate probit, instrumental variables model was used to estimate the effect of transfer to level I versus level II trauma centers on 30-day postdischarge mortality. Independent variables included age, gender, Injury Severity Scale (ISS), other indicators of injury severity, and a dichotomous variable indicating transfer to a level I trauma center. The differential distance between the nearest level I and level II trauma centers was used as an instrument.


RESULTS
Patients transferred to level I trauma centers differ in unmeasured ways from patients transferred to level II trauma centers, biasing estimates based on standard statistical methods. Transfer to a level I trauma center reduced absolute mortality risk by 10.1% (95% confidence interval 0.3%, 22.2%) compared with transfer to level II trauma centers.


CONCLUSIONS
Patients with severe head injuries transferred from rural trauma centers to level I centers are likely to have improved survival relative to transfer to level II centers.
McConnell
K John
KJ
Center for Policy and Research in Emergency Medicine, Department of Emergency Medicine, Oregon Health and Science University, Portland, OR, USA.
Newgard
Craig D
CD
Mullins
Richard J
RJ
Arthur
Melanie
M
Hedges
Jerris R
JR
D002391:Catchment Area, Health; D015331:Cohort Studies; D016001:Confidence Intervals; D006259:Craniocerebral Trauma / Q000145:classification / Q000401:mortality* / Q000534:rehabilitation; D004636:Emergency Service, Hospital; D006780:Hospitals, Rural / Q000592:standards / Q000706:statistics & numerical data; D006786:Hospitals, Urban / Q000592:standards / Q000706:statistics & numerical data; D006801:Humans; D015601:Injury Severity Score; D009922:Oregon / Q000453:epidemiology; D010360:Patient Transfer / Q000706:statistics & numerical data*; D012189:Retrospective Studies; D016019:Survival Analysis; D014187:Transportation of Patients / Q000706:statistics & numerical data; D014193:Trauma Centers / Q000145:classification* / Q000706:statistics & numerical data*; D014861:Washington / Q000453:epidemiology