Profound motorcycle risks: a national mileage exposure-adjusted analysis

Motorcycle crashes (MCC) account for a minority of vehicle miles in the United States, but their exposure-adjusted burden among trauma admissions is not well defined. The purpose of this study was to compare the injury burden of MCC versus motor vehicle crashes (MVC) using outcomes standardized by annual vehicle miles traveled (VMT).

A retrospective cohort study of American College of Surgeons Trauma Quality Programs (ACS-TQP) admissions from 2017 to 2023 was performed for adults aged 18-80 years admitted after MCC or MVC. Primary outcomes were admission, intensive care unit (ICU) admission, amputation, and in-hospital mortality per 100 million VMT using Federal Highway Administration denominators. Motorcycle VMT was used for MCC, and light-duty vehicle VMT was used for MVC. Secondary outcomes included Injury Severity Score thresholds (≥16 and ≥25), severe head/neck injury, open long-bone fracture, ventilation, and return to the operating room. Relative risks (RRs) were estimated using binomial regression models with a log link.

Among 1,419,094 admissions, 334,310 followed MCC and 1,084,784 followed MVC. MCC accounted for 23.6% of admissions but only 0.71% of included VMT. Per 100 million VMT, MCC had higher rates of admission (236.4 vs. 5.49; rate ratio, 43.0), ICU admission (70.8 vs. 1.57; rate ratio, 45.1), amputation (5.06 vs. 0.028; rate ratio, 183.0), and in-hospital mortality (6.4 vs. 0.12; rate ratio, 51.6). Among admitted patients, MCC was associated with higher risks of open long-bone fracture (14.7% vs. 6.6%; RR, 2.22), amputation (2.1% vs. 0.5%; RR, 4.25), and in-hospital mortality (2.7% vs. 2.2%; RR, 1.20).

MCCs contribute a disproportionately high burden of severe trauma in the United States, with higher mileage-adjusted rates of ICU admission, amputation, and in-hospital mortality than MVCs.