Commentary

Screening for alcohol problems in clinical practice remains challenging, at least in part because of the difficulty of easily obtaining an accurate alcohol history. The purpose of the meta-analysis by Aertgeerts et al was to assess the accuracy of the CAGE questions in screening for alcohol abuse and dependence in several different populations. These populations were limited to inpatients, ambulatory medical patients, and primary care patients to minimise heterogeneity. The authors included only studies involving a lifetime diagnosis of alcohol abuse or dependence using DSM criteria. Despite limiting the clinical populations, heterogeneity still existed among studies. This is not surprising because the studies still differed in clinically important ways, including patient age and ethnic background.

The authors concluded that the CAGE is of limited value at the recommended cut point of 2 positive responses. Overall, this is a reasonable conclusion, but closer examination of their results indicates that the CAGE still has considerable utility. Firstly, the LRs in ambulatory medical and primary care patients appear quite similar. In each group, the positive LR is about 8 at a cut point of 2, which is high enough to increase the probability of detection of an alcohol problem to a clinically important degree at the prevalences of alcohol abuse and dependence studied. The positive LR is lower among inpatients. Secondly, the LRs in ambulatory patients increase as the number of positive answers increases, providing additional information. As the authors note, their analysis did not support a single optimal cut point for all of the populations.

In summary, this well done meta-analysis suggests that the CAGE is more useful in identifying alcohol problems in ambulatory than hospital patients and confirms that additional information can be gained by considering the score as a graded measure rather than simply positive or negative.