Epidemiology and outcome analysis of blast injury patients in Japan: An analysis of the nationwide trauma registry database

Blast injuries in safe countries like Japan are understudied. This study examines nationwide data to reveal unique patterns, hypothesizing differences from conflict zones, and provides baseline insights for improving trauma care and disaster preparedness globally. This retrospective cohort study was conducted between 2004 and 2017 using a nationwide trauma registry in Japan. Data on patients with blast injuries were extracted from the registry and divided into 3 age groups: 0 to 15 years; 16 to 64 years; and 65-years. Data on patient demographics including age, gender, time of injury, cause of injury, and severity such as abbreviated injury scale for each component of the body and injury severity score (ISS) were analyzed among the groups. The examinations, treatment, and mortality were also assessed. The primary outcome of the study was the in-hospital mortality rate. We also performed subgroup analysis of patients with or without inhalation injuries. A total of 523 blast injury patients were treated during the study period. Among these, 18 belonged to the 0-15 year age group, 414 to the 16 to 64 year age group, and 91 to the 65-year age group. Males accounted for 83.4% of all patients. Most injuries were unintentional (56.2%), with all pediatric injuries occurring accidentally. The skin was the most frequently injured body part (84.3%) and a mean injury severity score was 9. Severe injuries (abbreviated injury scale ≥ 3) mainly involved burns. Only a single body area was damaged in 81.5% of all cases. Focused assessment with sonography for trauma was not performed in 66.5% of cases, and computed tomography scanning was not conducted in 67.7%. No surgery was performed in 67.1% of the cases. The overall in-hospital mortality rate was 6.1%, and the emergency department mortality rate was 1.5%. Intensive care unit admission was common (77.4%). Inhalation injuries were present in 31.5% of patients. These patients had higher intensive care unit admission rates (92.1%) compared to those without inhalation injuries (70.7%), and more frequent tracheal intubations (36.4% vs 15.4%). The study clarified the characteristics of blast injuries in Japan.