AUDITs Compared with Quantity-Frequency Criterion
Table 2 compares the likelihood of hazardous alcohol use, defined by a quantity-frequency criterion, associated with each score of the AUDIT, AUDIT-C, and AUDIT-3. It is important to note that at each score the true positives of screening are only persons identified at that score. For example, at an AUDIT score of 7, 53 of 754 hazardous drinkers were identified with the resulting likelihood ratio (3.0) and predictive value (26.9%).
For comparisons of the AUDIT, AUDIT-C, and AUDIT-3 at identifying hazardous drinkers who scored at or greater than a minimal cutoff, the sensitivity and specificity compared with a quantity-frequency criterion is shown in Table 3. For cut-point values of an AUDIT score of 8 or higher, the sensitivity of the AUDIT was 76%. Similarly, the sensitivities of the AUDIT-C (with score Ž3) and AUDIT-3 (with score Ž1) were 99.6% and 89.1%, as sensitive as the quantity-frequency questions in detecting these patients. Specificity of the AUDIT, AUDIT-C, and AUDIT-3 at these cutoff values was 92%, 48%, and 65%, respectively.
AUROCs were constructed from all cut-point values Figure 2. Computation of the AUROC indicates the effectiveness of the instrument to discriminate hazardous drinkers over a range of AUDIT scores. The AUROCs for the AUDIT, AUDIT-C, and AUDIT-3 were significantly more discriminating than the line of identity (AUROC=0.5). The AUROC of the AUDIT was significantly different from the AUDIT-C (z=2.69; P=.004). The AUDIT-3 AUROC was significantly different than the AUDIT (z=10.03; P <.001) and AUDIT-C (z=12.69; P <.001).
Abbreviated AUDITs Compared with Full AUDIT Criterion
The full AUDIT is often used as a standard to assess hazardous drinking. We compared the abbreviated instruments to the full AUDIT, with a positive score of 8 or higher as a criterion for such drinking. The AUDIT-C (score (3) and AUDIT-3 (score Ž1) were 94.9% and 99.9% as sensitive and 68.8% and 51.1% as specific as the full AUDIT in obtaining a positive score. We also determined the performance of the AUDIT-3 when compared with a reference standard of a positive AUDIT-C. The AUDIT-3 (score Ž1) was 69% sensitive and 95% specific as the AUDIT-C (score Ž3) at identifying hazardous drinkers (data not shown).
Discussion
We evaluated the performance of the AUDIT and abbreviated AUDIT instruments to detect hazardous drinking in a large multisite primary care sample. The abbreviated forms of the AUDIT were as effective as the AUDIT at identifying hazardous drinkers. Compared with quantity-frequency questions, the AUDIT and AUDIT-C were superior at identifying hazardous drinkers than the AUDIT-3. The abbreviated forms of the AUDIT were as sensitive as the full AUDIT at detecting hazardous drinkers when using standard cutoff values for hazardous drinking.
As with the 4-item CAGE questionnaire for alcohol dependence, a 1- or 3-item AUDIT instrument may increase care providers’ recognition of hazardous drinkers. Providers do not routinely ask standard alcohol questions, are particularly poor at identifying hazardous drinkers, and do not enter patients into alcohol treatment.16 Therefore, providing clinicians with a few easily remembered questions to determine hazardous drinking behavior would be beneficial.39 A short questionnaire would be simple to administer and applicable in a wide variety of practice settings. A positive response would increase suspicion regarding hazardous or abusive drinking behavior and prompt additional questions about patients’ alcohol use.18,40 For example, care providers could use the AUDIT-3 or AUDIT-C (to detect at least hazardous drinking), then administer the questionnaire (to detect abuse and dependence), if the patient’s response was positive.
It is important to realize that the AUDIT and its abbreviated forms are only sensitive to detect hazardous drinking, not to specifically assign patients’ drinking habits as hazardous only. The AUDIT was originally designed to distinguish a person with hazardous drinking from one with nonhazardous drinking.26 As such, this instrument may not be specific enough to distinguish hazardous drinkers from others with severe alcohol behaviors; people who score positive may qualify for alcohol abuse and dependence. For less risky alcohol behaviors, it is more important for a health care provider to identify all hazardous drinkers (true positives), at the risk of falsely identifying a person who may not have this behavior (false positives).18 Therefore, when screening to establish a threshold level of treatment intervention, screening instruments should maximize sensitivity, even at the expense of low specificity.
In our sample, the AUDIT (score Ž8), AUDIT-C (score Ž3), and AUDIT-3 (score Ž1) were as sensitive as quantity-frequency questions in detecting hazardous drinking. This increase in sensitivity of the AUDIT-C and AUDIT-3 is likely related to the consumption focus of these questions. The AUDIT-C consists of quantity and frequency type questions, and the third question is specific for quantity of drinking at one session. However, the performance of AUDIT instruments in our study is comparable and confirms results found in a study by Bush and colleagues,34 even though the studies used different criteria for assessment of abbreviated instruments.