Trends and outcomes of blunt renal trauma management: a nationwide cohort study in Japan

Background There is a paucity of information for predicting patient outcomes other than the American Association for the Surgery of Trauma (AAST) renal injury scale. The aim of this study was to evaluate the association between the patient characteristics and outcomes of patients with blunt renal trauma using a nationwide database in Japan. Methods We performed a retrospective analysis of the Japan Trauma Data Bank (JTDB) from 2004 to 2018. We identified patients with blunt renal trauma by AIS codes converted to AAST grades. We evaluated trends in patient characteristics and management and assessed factors associated with mortality and nephrectomy using a multivariable logistic regression analysis. Results We identified 3550 patients with blunt renal trauma. Their median age was 43 years and 74.2% were male. Nephrectomy was performed in 3.8%, and the overall mortality rate was 9.5%. We found increasing trends in age and emergency abdominal angiography and decreasing trends in nephrectomy and mortality over the 15-year period. The following factors were associated with mortality: age >= 65 years (adjusted OR 3.36); pedestrian accident (adjusted OR 1.94); fall from height (adjusted OR 1.91); shock on arrival (adjusted OR 4.02); concomitant injuries to the head/neck (adjusted OR 3.14), pelvis/lower-extremity (adjusted OR 1.59), liver (adjusted OR 1.68), spleen (adjusted OR 1.45), and gastrointestinal tract (adjusted OR 1.90); AAST grades III-V (adjusted ORs 1.42, 2.16, and 5.55); and emergency abdominal angiography (adjusted OR 0.70). The following factors were associated with nephrectomy: shock on arrival (adjusted OR 1.98), concomitant injuries to the thorax (adjusted OR 0.46) and spleen (adjusted OR 2.07), AAST grades III, IV, and V (adjusted ORs 18.40, 113.89, and 468.17), and emergency abdominal angiography (adjusted OR 0.28). Conclusions We demonstrated that the AAST grade and emergency angiography were associated with mortality and nephrectomy in blunt renal trauma in the Japanese population.