We used ICD-9/10 codes to identify subjects diagnosed with AUD (either alcohol abuse or dependence) codes. The codes are based on the work of Piette et al. (16) and are included in on-line supplementary material. Participants were considered to have a diagnosis of AUD if they had at least one inpatient or two outpatient alcohol-related ICD-9 or ICD-10 codes. This requirement has been shown to improve the specificity of ICD codes compared to chart review (17). Of note, we chose not to include codes consistent with alcohol-related conditions (e.g., alcoholic cirrhosis), as we wanted to create a phenotype of drinking behavior, not its complications, to which different genetic variants may contribute.
