Systematic review of published evidence regarding trauma system effectiveness

Objective—To provide a systematic review of the published literature assessing the effect of trauma centre/system implementation on patient outcomes.

Methods—A search of Medline, HealthSTAR, and CINAHL yielded 245 papers with 39 additional manuscripts identified by references of reviewed manuscripts. Literature was restricted to United States and Canadian studies. The strength of evidence associated with each article was critically appraised by a three tier classification system developed to assess the traumatic brain injury literature. Class I studies were prospective randomised controlled trials. Class II studies were well designed prospective or retrospective controlled cohort studies, or case-control studies. Class III studies were other quasi-experimental studies that use existing databases, registries, or relied on case series data.

Results—42 papers were included in the critical appraisal review. This review found mainly Class III evidence, which consisted of three different study types; “Panel studies” used expert panels to determine whether trauma systems are effective in reducing preventable death. The authors pointed out a number of possible sources of bias in this methodology including the use of local assessors with knowledge of the system, lack of blinding to the centre of treatment (trauma centre or not), and the varying quality of injury information of necropsy reporting. “Comparisons to National injury registries” used mostly Major Trauma Outcome Study (MTOS) methodology to examine numbers of expected deaths against numbers of observed deaths. However, there were inconsistencies with data collection protocols, case mix and injury demographics and criticisms that MTOS data are not population based. This led to the authors classifying such comparisons as Class III evidence. “Population-based studies” used larger databases, including claims and vital statistic data, which permitted trauma system assessment within an entire region or state, commonly using pre-system versus post-system, or trauma …