Crash-related factors associated with the severity of road traffic injuries in Iran.

Although the impact of traffic crashes is very high in Iran, there are few works on the association of crash-related factors with injury severity. This study was conducted on 145 drivers injured on the Qazvin-Loshan road in order to assess this association. The New Injury Severity Score (NISS), based on the conditions of the injured drivers during their first visit to regional hospitals, was used as the main outcome measure. Multiple linear regression analysis was performed by considering logarithmic scale for NISS as response variable and adjusting for the confounding effects, including the transfer to hospital variables. The results showed that high-vehicle damage (i.e. damage with repair cost more than 25% of the pre-crash value of the driver's vehicle) and being trapped inside the motor vehicle raised the NISS by 5.25 (95% confidence interval (CI) 2.51-10.71) and 2.34 (95% CI 1.20-4.67), respectively.