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.