Risk factors that predict mortality in patients with blunt chest wall trauma: an updated systematic review and meta-analysis

Background Over the last 10 years, research has highlighted emerging potential risk factors for poor outcomes following blunt chest wall trauma. The aim was to update a previous systematic review and meta-analysis of the risk factors for mortality in blunt chest wall trauma patients. Methods A systematic review of English and non-English articles using MEDLINE, Embase and Cochrane Library from January 2010 to March 2022 was completed. Broad search terms and inclusion criteria were used. All observational studies were included if they investigated estimates of association between a risk factor and mortality for blunt chest wall trauma patients. Where sufficient data were available, ORs with 95% CIs were calculated using a Mantel-Haenszel method. Heterogeneity was assessed using the I-2 statistic. Results 73 studies were identified which were of variable quality (including 29 from original review). Identified risk factors for mortality following blunt chest wall trauma were: age 65 years or more (OR: 2.11; 95% CI 1.85 to 2.41), three or more rib fractures (OR: 1.96; 95% CI 1.69 to 2.26) and presence of pre-existing disease (OR: 2.86; 95% CI 1.34 to 6.09). Other new risk factors identified were: increasing Injury Severity Score, need for mechanical ventilation, extremes of body mass index and smoking status. Meta-analysis was not possible for these variables due to insufficient studies and high levels of heterogeneity. Conclusions The results of this updated review suggest that despite a change in demographics of trauma patients and subsequent emerging evidence over the last 10 years, the main risk factors for mortality in patients sustaining blunt chest wall trauma remained largely unchanged. A number of new risk factors however have been reported that need consideration when updating current risk prediction models used in the ED.