Study designs of evaluations included in the review
Only studies that included consecutive patients or a random sample of patients were included.
Specific interventions included in the review
Studies that assessed the CAGE questionnaire as an independent questionnaire were eligible for inclusion. Studies that embedded CAGE in a larger questionnaire were included if the four CAGE questions were kept together.
Reference standard test against which the new test was compared
Studies had to use the American Psychiatric Association's DSM criteria for the diagnosis of alcohol abuse or dependence as the reference standard. Studies in which only patients who screened positive on CAGE received the reference standard interview were excluded, as were studies in which less than 50% of the initially defined study population received the reference standard. Studies in which all screen-positive patients and a random sample of the screen-negative patients received the reference standard were included.
Participants included in the review
Only studies conducted in general clinical populations were included. Studies conducted in psychiatric or emergency departments were excluded. The studies had to provide a good description of the study population so that it could be classified as in-patient or out-patient, and as belonging to primary care or a general hospital population. The included studies involved in-patients, ambulatory medical patients and primary care patients; most studies included patients with specified minimum ages that ranged from 16 to 65 years.
Outcomes assessed in the review
The studies had to provide sufficient data to calculate diagnostic value indicators at all different thresholds for the CAGE questionnaire.
How were decisions on the relevance of primary studies made?
Two reviewers independently assessed studies for inclusion. Any disagreements were resolved by referral to a third reviewer.