Validity of self-reports of drinking before injury by cause of injury and societal context among emergency department patients.

INTRODUCTION AND AIMS: Validity of self-reported alcohol consumption is a topic of continued interest with mixed findings. Validity of self-reports prior to injury is analysed among emergency department (ED) patients by cause of injury, blood alcohol concentration (BAC) and societal context. DESIGN AND METHODS: Data are on 16 196 injured patients from 23 countries in the International Collaborative Alcohol and Injury Project. The proportion of those reporting drinking within 6 h prior to injury among the 2658 BAC positive patients was analysed by injury cause (traffic, violence, falls, other), BAC level (0.01-0.079 mg%, ≥ 0.08 mg%), detrimental drinking pattern (DDP) and the International Alcohol Policy and Injury Index (IAPII).
RESULTS: Validity averaged 92%, ranging from 85% for drivers to 95% for violence-related injuries. Validity was significantly lower at lower BAC levels for all injuries (P < 0.01) and for violence and falls. Countries with a high DDP and those with lower IAPII scores (less restrictive alcohol policy) also appeared more likely to deny drinking which was significant for DDP for falls (P < 0.01) and for IAPII for passengers/pedestrians (P < 0.05) and violence (P < 0.05). Validity was highest for high IAPII countries, ranging from 92% to 99%. DISCUSSION AND
CONCLUSIONS: Validity of self-report compared to breathalyzer readings at the time of admission to the ED was high, but varied by cause of injury, BAC level, country-level detrimental drinking patterns and the restrictiveness of alcohol control policy. Findings may support the utility or self-reports as an alternative to a quantifiable measure of BAC in the ED setting.