State-Level Helmet Use Laws, Helmet Use, and Head Injuries in EMS Patients Involved in Motorcycle Collisions

Objectives: Motorcycle helmets save lives and reduce serious injury after motorcycle collisions (MCC). In 2022, 18 states had laws requiring helmet use by motorcyclists aged ≥21 years. Our objective was to compare helmet use and head trauma in emergency medical services (EMS) patients involved in MCC in states with and without helmet use laws.

Methods: We conducted an analysis of the 2022 ImageTrend Collaborate national EMS dataset. We included 9-1-1 responses where the patient was a motorcyclist in a transport accident (ICD-10 V20-V29) and aged ≥21 years. Patient demographics, incident urbanicity, helmet use, presence of state helmet use law, patient disposition, Glasgow Coma Scale (GCS) score, and trauma team activations were examined. Our primary outcome of interest was EMS documentation of helmet use (yes/no). Our secondary outcome was the presence of a head injury. We examined EMS-documented head injury, defined using clinician impressions and chief complaint anatomical location. Chi-square tests were used to assess differences in proportions, and a multivariable logistic regression model was used to estimate odds of moderate/severe head injury adjusted for covariates of interest.

Results: A total of 15,891 patient encounters were included, 10,738 (67.6%) occurred in states without helmet use laws. States without helmet use laws had higher proportions of unhelmeted patients (56.8% vs 24.2%, p < 0.001), encounters in non-metro/rural areas (19.7% vs 13.3%, p < 0.001), and GCS-defined moderate/severe head injuries (4.6% vs 2.3%, p < 0.001). In a multivariable model that included 10-yr age groups, sex, race, urbanicity, and documented helmet use, the adjusted odds of moderate/severe head injury were lower for females (0.47, 95%CI, 0.35-0.65) and Black patients (0.47, 95%CI 0.32-0.70), and were higher for incidents in nonmetro/rural areas (1.58, 95%CI 1.28-1.95) and when EMS had not documented helmet use (3.17, 95%CI 2.56-3.92).

Conclusions: In this retrospective cross-sectional study, a higher proportion of patients involved in MCCs in states without helmet laws were not wearing helmets at the time of injury, and unhelemted patients had increased likelihood of sustaining a head injury. Emergency medical services agencies in states without helmet laws should prepare their systems and clinicians for an increased incidence of head injuries after MCCs.