Risk Factors of Significant Pain Syndrome 90 Days After Minor Thoracic Injury: Trajectory Analysis

ObjectivesThe objective was to identify the risk factors of clinically significant pain at 90days in patients with minor thoracic injury (MTI) discharged from the emergency department (ED). MethodsA prospective, multicenter, cohort study was conducted in four Canadian EDs from November 2006 to November 2010. All consecutive patients aged 16years or older with MTI were eligible at discharge from EDs. They underwent standardized clinical and radiologic evaluations at 1 and 2weeks, followed by standardized telephone interviews at 30 and 90days. A pain trajectory model characterized groups of patients with different pain evolutions and ascertained specific risk factors in each group through multivariate analysis. ResultsIn this cohort of 1,132 patients, 734 were eligible for study inclusion. The authors identified a pain trajectory that characterized 18.2% of the study population experiencing clinically significant pain (>3 of 10) at 90days after a MTI. Multivariate modeling found two or more rib fractures, smoking, and initial oxygen saturation below 95% to be predictors of this group of patients. ConclusionsTo the authors' knowledge, this is the first prospective study of trajectory modeling to detect risk factors associated with significant pain at 90days after MTI. These factors may help in planning specific treatment strategies and should be validated in another prospective cohort.