title: The effect of interfacility transfer on outcome in an urban trauma system.
abstract: BACKGROUND
  Transporting all trauma patients to regional trauma centers is inefficient; however, the bypass of nearer, nondesignated hospitals in deference to regional trauma centers decreases mortality in the severely injured. One approach to improving efficiency is to allow the initial assessment of selected patients at lower level (Level III/IV) designated centers. We set out to evaluate whether patients initially assessed at these centers and then transferred to a Level I facility were adversely affected by delays to definitive care.
  
  
  METHODS
  This is a retrospective cohort study in which the primary exposure being evaluated is initial assessment at a Level III or IV trauma center before transport to a Level I center in an urban setting. The outcomes in this transfer cohort were compared with outcomes in patients transported directly from the scene to a Level I center (direct cohort). The outcomes of interest were mortality, length of stay, and hospital charges. Multivariate analyses were used to adjust for differences in baseline characteristics across these two cohorts.
  
  
  RESULTS
  Crude length of stay was comparable, whereas mortality was lower and charges were 40% higher in the transfer cohort (n = 281) compared with the direct cohort (n = 4,439). After adjusting for confounders, mortality and length of stay were similar and total charges were significantly greater in the transferred patients.
  
  
  CONCLUSIONS
  Interfacility transfers in a mature urban trauma system do not appear to impact on clinical outcome. However, transfer patients use significantly greater resources as measured by hospital charges. This effect is likely because of the nature of their injuries or, alternatively, delays in reaching definitive care.
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D005260:Female; D006760:Hospitalization / Q000191:economics*; D006801:Humans; D015601:Injury Severity Score; D007902:Length of Stay; D008297:Male; D008875:Middle Aged; D010043:Outcome and Process Assessment, Health Care; D010360:Patient Transfer / Q000706:statistics & numerical data*; D012189:Retrospective Studies; D014193:Trauma Centers / Q000145:classification / Q000191:economics; D014505:Urban Population; D014861:Washington; D014947:Wounds and Injuries / Q000145:classification* / Q000209:etiology / Q000401:mortality