A comparison of patient characteristics and survival in two trauma centreslocated in different countries

Introduction: The aim of the study was to compare patient characteristics a nd mortality in severely injured patients in two trauma centres located in different countries. allowing for differences in case-mix. It represents a direct bench-marking exercise between the trauma centres at the North Staff ordshire Hospital (NSH), Stoke-on-Trent, UK and the Oregon Health Sciences University (OHSU) Hospital, Portland, Oregon, USA. Methods: Patients of all ages admitted to the two hospitals during 1995 and 1996 with an Injury Severity Score > 15 were included. except for those wh o died in the emergency departments. Twenty-three factors were studied, inc luding the Injury Severity Score, Glasgow Coma Score, mechanism of injury a nd anatomical site of injury. Outcome analysis was based on mortality at di scharge. Results: The pattern of trauma differed significantly between Stoke and Por tland. Patients from Stoke tended to be older, presented with a lower consc ious level and a lower systolic blood pressure and were intubated less freq uently before arriving at hospital, Mortality depended on similar factors i n both centres, especially age, highest AIS score, systolic blood pressure and Glasgow Coma Score. The crude analysis of mortality showed a highly significant odds-ratio of 1 .64 in Stoke compared with Portland. Single-factor adjustments were made fo r the above four factors, which had a similar influence on mortality in bot h centres. Adjusting for the first three factors individually did not alter the odds-ratio, which stayed in the range 1.53-1.59 and remained highly si gnificant. Adjusting for the Glasgow Coma Score reduced the odds-ratio to 0 .82 and rendered it non-significant. In a multi-factor logistic regression model incorporating all of the factors shown to influence mortality in eith er centre, the odds-ratio was 1.7 but was not significant. Conclusion: The analysis illustrates the limitations and pitfalls of making crude outcome comparisons between centres. Highly significant differences in crude mortality were rendered non-significant by case-mix adjustments, s upporting the null hypothesis that the two centres were equally effective i n terms of this short-term indicator of outcome. To achieve a meaningful co mparison between centres. adjustments must be made for the factors which af fect mortality. (C) 2000 Elsevier Science Ltd. All rights reserved.