PMID- 25972600 OWN - NLM STAT- MEDLINE DCOM- 20160906 LR - 20181113 IS - 1475-5785 (Electronic) IS - 1353-8047 (Print) IS - 1353-8047 (Linking) VI - 21 IP - 6 DP - 2015 Dec TI - Does transport time help explain the high trauma mortality rates in rural areas? New and traditional predictors assessed by new and traditional statistical methods. PG - 367-73 LID - 10.1136/injuryprev-2014-041473 [doi] AB - BACKGROUND: Trauma is a leading global cause of death. Trauma mortality rates are higher in rural areas, constituting a challenge for quality and equality in trauma care. The aim of the study was to explore population density and transport time to hospital care as possible predictors of geographical differences in mortality rates, and to what extent choice of statistical method might affect the analytical results and accompanying clinical conclusions. METHODS: Using data from the Norwegian Cause of Death registry, deaths from external causes 1998-2007 were analysed. Norway consists of 434 municipalities, and municipality population density and travel time to hospital care were entered as predictors of municipality mortality rates in univariate and multiple regression models of increasing model complexity. We fitted linear regression models with continuous and categorised predictors, as well as piecewise linear and generalised additive models (GAMs). Models were compared using Akaike's information criterion (AIC). RESULTS: Population density was an independent predictor of trauma mortality rates, while the contribution of transport time to hospital care was highly dependent on choice of statistical model. A multiple GAM or piecewise linear model was superior, and similar, in terms of AIC. However, while transport time was statistically significant in multiple models with piecewise linear or categorised predictors, it was not in GAM or standard linear regression. CONCLUSIONS: Population density is an independent predictor of trauma mortality rates. The added explanatory value of transport time to hospital care is marginal and model-dependent, highlighting the importance of exploring several statistical models when studying complex associations in observational data. CI - Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/ FAU - Roislien, Jo AU - Roislien J AD - Department of Health Sciences, University of Stavanger, Stavanger, Norway Department of Biostatistics, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway. FAU - Lossius, Hans Morten AU - Lossius HM AD - Department of Health Sciences, University of Stavanger, Stavanger, Norway Department of Research, Norwegian Air Ambulance Foundation, Drobak, Norway. FAU - Kristiansen, Thomas AU - Kristiansen T AD - Department of Research, Norwegian Air Ambulance Foundation, Drobak, Norway Department of Anaesthesiology, Vestre Viken Hospital Trust, Drammen, Norway. LA - eng PT - Journal Article DEP - 20150513 PL - England TA - Inj Prev JT - Injury prevention : journal of the International Society for Child and Adolescent Injury Prevention JID - 9510056 SB - IM MH - Age Factors MH - Humans MH - *Models, Statistical MH - Multiple Trauma/*mortality MH - Multivariate Analysis MH - Norway/epidemiology MH - Population Density MH - Registries MH - Risk Factors MH - Rural Population/*statistics & numerical data MH - Time Factors MH - Transportation of Patients/*statistics & numerical data PMC - PMC4717406 EDAT- 2015/05/15 06:00 MHDA- 2016/09/07 06:00 PMCR- 2016/01/19 CRDT- 2015/05/15 06:00 PHST- 2014/10/22 00:00 [received] PHST- 2015/03/27 00:00 [accepted] PHST- 2015/05/15 06:00 [entrez] PHST- 2015/05/15 06:00 [pubmed] PHST- 2016/09/07 06:00 [medline] PHST- 2016/01/19 00:00 [pmc-release] AID - injuryprev-2014-041473 [pii] AID - 10.1136/injuryprev-2014-041473 [doi] PST - ppublish SO - Inj Prev. 2015 Dec;21(6):367-73. doi: 10.1136/injuryprev-2014-041473. Epub 2015 May 13.