Using trauma center data to identify missed bicycle injuries and their associated costs

Recently, there has been a 58% increase in the number of observed cyclists in San Francisco. In 2009, 3.2% of commuters were traveling by bicycle in this city, which is well above the national average of less than 1%. Police reports are the industry standard for assessing transportation-related collisions and informing policies and interventions that address the issue. Previous studies have suggested that police reports miss a substantial portion of bicycle crashes not involving motor vehicles. No study to date has explored the health and economic impact of cyclist-only (CO) injuries for adults in the United States. Our objective was to use trauma registry data to investigate possible underrepresentation of certain cyclist injuries and characterize cost.

We reviewed hospital and police records for 2,504 patients treated for bicycle-related injuries at San Francisco General Hospital (SFGH). We compared incidence, injury severity, admission rate, and cost of injury for CO and auto-versus-bicycle (AVB) injuries treated at SFGH. We then calculated the cost of injury.

Of all bicycle-related injuries at SFGH, 41.5% were CO injuries and 58.5% were AVB injuries. Those with CO injuries were more than four times as likely to be required of hospital admission compared with those with AVB injuries (odds ratio, 4.76; 95% confidence interval, 3.93-5.76; p < 0.0001). From 2000 to 2009, 54.5% of bicycle injuries treated at SFGH were not associated with a police report, revealing that bicycle crashes and injuries are underrecognized in San Francisco. Costs for care were significantly higher for AVB injuries and increased dramatically over time; total cost for CO and AVB injuries were $12.6 and $17.8 million.

Based on this study, we conclude that trauma centers can play a key role in future collaborations to define issues and develop prevention strategies for CO crashes.

Epidemiologic study, level II.