Assessing the impact of the national traffic safety campaign: a nationwide cohort study in Japan

OBJECTIVES: This study aimed to examine the difference in mortality from serious road traffic injuries during the National Traffic Safety Campaign compared with other periods and identify the common mechanisms of injury by age group in Japan. DESIGN: A retrospective review of Japan Trauma Data Bank (JTDB). SETTING: A total of 280 participating major emergency institutions across Japan. PARTICIPANTS: Patients with road traffic injuries registered in JTDB between 2004 and 2018 were recruited in the study. We included patients injured by traffic crashes during the National Traffic Safety Campaigns and controls using a double control method. The National Traffic Safety Campaign comprises 10 consecutive days in spring and fall (20 days in each year), and controls was the same calendar days 2 weeks before and after the days in the National Traffic Safety Campaigns (40 days in each year) to control for weekday, seasonal and yearly trends. PRIMARY AND SECONDARY OUTCOME MEASURES: The primary outcome was in-hospital mortality. The secondary outcome was the incidences of severe traffic injury. RESULTS: Among 126 857 patients recorded as road traffic injuries in JTDB, we identified 6181 patients (21 cases per day) with injuries occurring during the National Traffic Safety Campaigns and 12 382 controls (21 cases per day). The overall in-hospital mortality was 11.4%. We did not observe a significant difference in in-hospital mortality between the groups (11.8% vs 11.1%) with an adjusted OR of 1.05 (95% CI 0.95 to 1.16). The most common mechanism of injury in each age group was bicycle crash among children, motorcycle crash among adults and pedestrian among the elderly. CONCLUSIONS: We found no change in the incidence of severe traffic injury or in-hospital mortality during the National Traffic Safety Campaign in Japan. Serious road trauma was high for bicycles among children, motorcycles among adults and pedestrian among the elderly.