Factors associated with prolonged on-scene time in ambulance transportation among patients with minor diseases or injuries in Japan: a population-based observational study

Abstract Background Prolonged prehospital time is a major global problem in the emergency medical system (EMS). Although factors related to prolonged on-scene times (OSTs) have been reported in patients with trauma and critical medical conditions, those in patients with minor diseases or injuries remain unclear. We examined factors associated with prolonged OSTs in patients with minor diseases or injuries. Methods This population-based observational study used the ambulance transportation and request call record databases of the Higashihiroshima Fire Department, Japan, between January 1, 2016, and December 31, 2022. The participants were patients with minor diseases or injuries during the study period. We performed a multivariable logistic regression analysis with robust error variance to examine the association between patient age, sex, severity, accident type, date and time of ambulance call, and the coronavirus disease 2019 (COVID-19) pandemic with prolonged OSTs. Prolonged OST was defined as ≥ 30 min from the ambulance arrival at the scene to departure. Results Of the 60,309 people transported by ambulance during the study period, 20,069 with minor diseases or injuries were included in the analysis. A total of 1,241 patients (6.2%) experienced prolonged OSTs. Fire accidents (adjusted odds ratio [aOR]: 7.77, 95% confidence interval [CI]: 3.82–15.79), natural disasters (aOR: 28.52, 95% CI: 2.09–389.76), motor vehicle accidents (aOR: 1.63, 95% CI: 1.30–2.06), assaults (aOR: 2.91, 95% CI: 1.86–4.53), self-injuries (aOR: 5.60, 95% CI: 3.37–9.32), number of hospital inquiries ≥ 4 (aOR: 77.34, 95% CI: 53.55–111.69), and the COVID-19 pandemic (aOR: 2.01, 95% CI: 1.62–2.50) were associated with prolonged OSTs. Moreover, older and female patients had prolonged OSTs (aOR: 1.18, 95% CI: 1.01–1.36 and aOR: 1.12, 95% CI: 1.08–1.18, respectively). Conclusions Older age, female sex, fire accidents, natural disasters, motor vehicle accidents, assaults, self-injuries, number of hospital inquiries ≥ 4, and the COVID-19 pandemic influenced prolonged OSTs among patients with minor diseases or injuries. To improve community EMS, we should reconsider how to intervene with potentially modifiable factors, such as EMS personnel performance, the impact of the presence of allied services, hospital patient acceptance systems, and cooperation between general emergency and psychiatric hospitals.