Item bias in the CAGE screening test for alcohol use disorders

OBJECTIVE: To explore potential item bias in the CAGE questions (mnemonic for cut-down, annoyed, guilty, and eye-opener) when used to screen for alcohol use disorders in primary care patients. DESIGN AND SETTING: Cross-sectional study, conducted in a university-based, family practice clinic, with the presence of an alcohol use disorder determined by structured diagnostic interview using the Alcohol Use Disorder and Associated Disabilities Interview Schedule. PATIENTS: A probability sample of 1,333 adult primary care patients, with oversampling of female and minority (African-American and Mexican-American) patients. MAIN RESULTS: Unadjusted analyses showed marked differences in the sensitivity and specificity of each CAGE question against a lifetime alcohol use disorder, across patient subgroups. Women, Mexican-American patients, and patients with annual incomes above $40,000 were consistently less likely to endorse each CAGE question 'yes,' after adjusting for the presence of an alcohol use disorder and pattern of alcohol consumption. In results from logistic regression analyses predicting an alcohol use disorder, cut-down was the only question retained in models for each of the subgroups. The guilty question did not contribute to the prediction of an alcohol use disorder: annoyed and eye-opener were inconsistent predictors. CONCLUSIONS: Despite its many advantages, the CAGE questionnaire is an inconsistent indicator of alcohol use disorders when used with male and female primary care patients of varying racial and ethnic backgrounds. Gender and cultural differences in the consequences of drinking and perceptions of problem alcohol use may explain these effects. These biases suggest the CAGE is a poor 'rule-out' screening test. Brief and unbiased screens for alcohol use disorders in primary care patients are needed.