Validity of self-reported alcohol consumption in the emergency room: data from the United States, Mexico and Spain

The validity of self-reported alcohol consumption within 6 hours prior to injury based on breath-analyzer readings obtained at the time of emergency room (ER) admission is compared among probability samples of ER patients in Contra Costa County, California (n = 450), Mexico City (n = 500) and Barcelona, Spain (n = 864). The same questionnaire, study design and methods were used in all three countries to maintain comparability for comparative analyses. The analysis was restricted to those breath analyzed within 6 hours of injury occurrence who reported no drinking following the event. Validity of self-reports was high in all three samples. The proportion of those reporting not drinking prior to injury who had positive breath-analyzer readings was .5% in the U.S., 1.5% in Spain and 3.3% in Mexico. Validity of self-reports was not associated with cause of injury in the United States. In Mexico those injured in motor vehicle accidents or by violence were most likely to deny drinking, while in Spain those injured in violent situations were most likely to report not drinking. Validity of self-reports in these studies is much higher than that found in other U.S. studies, but this may be partly due to the fact that self-reports were obtained after the patient had been breath analyzed.