The effect of socio-economic status on non-fatal outcome after injury: a systematic review

Background: Over the past decades, the number of survivors of injuries has rapidly grown. It has become important to focus more on the determinants of non-fatal outcome. Although socio-economic status (SES) is considered to be a fundamental determinant of health in general, the role of SES as a determinant of non-fatal outcome after injury is largely unknown.
Methods: An online search was conducted in November 2015 using Embase, Medline, Web of Science, Cinahl, Cochrane, Google scholar and PubMed. Studies examining the relation between SES and a physical or psychological outcome measure, or using SES as a confounder in a general trauma population were included. There were no restrictions regarding study design. The 'Quality in Prognostic Studies tool' was used to assess the methodological quality of the included studies.
Results: The 24 included studies showed large variations in methodological quality. The number of participants ranged from 56 to 4639, and assessments of the measures ranged from immediately to 6. year post-injury. Studies used a large number of variables as indicators of SES. Participant's educational level was used most frequently. The majority of the studies used a multivariable technique to analyse the relation between SES and non-fatal outcome after injury. All studies found a positive association (80% of studies significant, n = 19) between increased SES and better non-fatal outcome after injury.
Conclusion: Although an adequate and valid measure of SES is lacking, the results of this review showed that SES is an important determinant of non-fatal outcome after injury. Future research should focus on the definition and measurement of SES and should further underpin the effect of SES on non-fatal outcome after injury.