Renson A, et al. - Researchers intended to determine the impact of the seatbelt use alone or along with airbag on risk of severe liver injury. It has been already established that seatbelt use, alone and in conjunction with an airbag, is associated with lower risk of mortality, blunt abdominal trauma and kidney injury in motor vehicle crashes (MVCs). Lower liver injury severity was reported in relation to use of seatbelts, which when used in conjunction with an airbag, provided more protection. Airbags without seatbelt use were shown to be not protective against severe injury among patients with liver injury.

• In this retrospective cohort study, patient admissions with liver injuries from MVCs from the National Trauma Data Bank (NTDB), collected from 2010 to 2015 in the USA, were included.
• Researchers assessed links between injury severity and seatbelt use and airbag presence individually and in the presence of additive interaction.
• Mortality, complications and discharge disposition were assessed as secondary outcomes.

• A total of 55,543 records were analyzed.
• Adjusted analysis revealed that seatbelt use alone was protective against severe (AAST VI or above) hepatic injury (risk ratio (RR) 0.79, 95% CI 0.75 to 0.84), while airbag presence alone was not (RR 1.05, 95% CI 0.8 to 1.12).
• Relative to seatbelts alone, joint association of seatbelt use and airbag presence with injury severity was noted to be greater (RR 0.74, 95% CI 0.70 to 0.79), with 13% of the joint lower risk attributable to interaction (95% CI 3% to 24%).
• Researchers noted that in comparison to patients who used a seatbelt in conjunction with a present airbag (5.3%, n=699, p<0.001), those without protective devices (10.3%, n=2297) had nearly double adjusted mortality risk.