Retrospective validation of the STUMBL score in a Level 1 trauma centre

Chest trauma is a common presentation to major trauma centres. Risk assessment tools have proven useful to support decision making in this group and the STUMBL (STUdy of the Management of BLunt chest wall trauma) score is one such measure that has been increasingly utilised. The aim of this study was to retrospectively validate the STUMBL score in an Australian population of patients admitted following chest trauma.

Methods: A single-centre retrospective validation study was undertaken using information from all patients with an Emergency Department (ED) attendance for isolated blunt chest trauma at a major trauma centre in Australia from 2018. The performance of the STUMBL score was measured including the cut-off score which best predicted 1) the discharge disposition from ED (ward or intensive care unit [ICU]), 2) the development of pulmonary complications, 3) an extended length of stay (LOS) (7 days or more) and 4) any complication (pulmonary, extended LOS, in hospital mortality). The performance measures included sensitivity, specificity, negative and positive predictive values as well discrimination and calibration.

Results: There were 300 patients admitted between 1st January 2018 and 31st December 2018 with a median age of 60 years (IQR 44-75) and 65 % were male. The risk prediction cut-off score for our patient cohort ranged from 18.5 for LOS 7 days or more to 11.5 for ward admission from ED. The positive predictive value (PPV) ranged from 56.7 % for ward admission from ED to 21.1 % for pulmonary complications. The negative predictive value (NPV) and sensitivity was highest for ICU admission from ED (96.5 % and 80.6 %) and the specificity ranged from 78 % for all complication prediction to 65.3 % for LOS of 7 or more days. The C statistic ranged from 0.82 for ICU admission to 0.65 for pulmonary morbidity.

Conclusion: The performance measures of the STUMBL score are suboptimal in our population. The best performing measure was the ability to predict ICU admission. Further validation work that includes additional factors may improve the positive predictive value and clinical utility of the score in our cohort.