Comparison of the Incidence and Severity of Traumatic Brain Injury Caused by Electrical Bicycle and Bicycle Accidents—A Retrospective Cohort Study From a Swiss Level I Trauma Center

Abstract

Electrical bicycles (E-bikes) allow people of all ages to ride at high speeds but have an inherent risk of traumatic brain injury (TBI). Their sales have increased tremendously in recent years. We performed a retrospective cohort study to compare the incidence and severity of TBI in E-bikers and conventional bicyclists. We included patients at a Swiss level 1 trauma center admitted from 2010 to 2015. The primary outcome was the association between TBI and the bicycle type. The secondary outcome was the association between helmet use and TBI severity. Of 557 patients injured riding an E-bike (n= 73) or a bicycle (n= 484), 60% sustained a TBI, most of which were mild (Glasgow coma scale [GCS] score, 13-15; E-bike, 78%; bicycle, 88%). TBI was more often moderate (GCS score, 9-12) or severe (GCS score, 3-8) in E-bikers than in bicyclists (P= 0.04). Intracranial hemorrhage, traumatic subarachnoid hemorrhage, and subdural hematoma occurred significantly more often in E-bikers than in bicyclists (P < 0.05). Neurosurgical intervention was necessary for 5 E-bikers (7%) and 25 (5%) bicyclists (P= 0.15). Wearing a helmet correlated with a lower risk of neurosurgical intervention in bicyclists (odds ratio [OR], 0.21; 95% confidence interval [CI], 0.06-0.73; P= 0.01) and a lower risk of calvarial fractures in both bicyclists (OR, 0.16; 95% CI, 0.06-0.42; P < 0.01) and E-bikers (OR, 0.21; 95% CI, 0.05-0.84; P= 0.03). E-bikers had a significantly greater risk of moderate to severe TBI compared with bicyclists. Helmet use was associated with decreased odds of severe TBI in bicyclists and a tendency toward a more favorable outcome for E-bikers.