Recent trends in 30-day mortality in patients with blunt splenic injury: A nationwide trauma database study in Japan

BACKGROUND:Splenic injury frequently occurs after blunt abdominal trauma; however, limited epidemiological data regarding mortality are available. We aimed to investigate mortality rate trends after blunt splenic injury in Japan. METHODS:We retrospectively identified 1,721 adults with blunt splenic injury (American Association for the Surgery of Trauma splenic injury scale grades III-V) from the 2004-2014 Japan Trauma Data Bank. We grouped the records of these patients into 3 time phases: phase I (2004-2008), phase II (2009-2012), and phase III (2013-2014). Over the 3 phases, we analysed 30-day mortality rates and investigated their association with the prevalence of certain initial interventions (Mantel-Haenszel trend test). We further performed multiple imputation and multivariable analyses for comparing the characteristics and outcomes of patients who underwent TAE or splenectomy/splenorrhaphy, adjusting for known potential confounders and for within-hospital clustering using generalised estimating equation. RESULTS:Over time, there was a significant decrease in 30-day mortality after splenic injury (p < 0.01). Logistic regression analysis revealed that mortality significantly decreased over time (from phase I to phase II, odds ratio: 0.39, 95% confidence interval: 0.22-0.67; from phase I to phase III, odds ratio: 0.34, 95% confidence interval: 0.19-0.62) for the overall cohort. While the 30-day mortality for splenectomy/splenorrhaphy diminished significantly over time (p = 0.01), there were no significant differences regarding mortality for non-operative management, with or without transcatheter arterial embolisation (p = 0.43, p = 0.29, respectively). CONCLUSIONS:In Japan, in-hospital 30-day mortality rates decreased significantly after splenic injury between 2004 and 2014, even after adjustment for within-hospital clustering and other factors independently associated with mortality. Over time, mortality rates decreased significantly after splenectomy/splenorrhaphy, but not after non-operative management. This information is useful for clinicians when making decisions about treatments for patients with blunt splenic injury.