A single-question screen was sensitive and specific for the detection of unhealthy alcohol use in a sample of primary care patients. Its test characteristics were similar to those of a longer screening tool in this sample, as well as in numerous studies reported in the literature13,20–23
Unhealthy alcohol use is prevalent in primary care, and brief intervention in this setting effectively reduces consumption among those without dependence, and improves patient outcomes1,2
. Lack of detection of unhealthy alcohol use, however, stands as a barrier to such treatment6
. Time constraints in the primary care setting have been cited as a reason for non-adherence to screening and prevention guidelines in general, and for the under-diagnosis of unhealthy alcohol use specifically (according to one estimate, providing all recommended preventive services to an average primary care panel would require 7.4 hours out of each work day)24
. Among the best validated options for alcohol screening in primary care settings are the CAGE questionnaire, the AUDIT, and the MAST25–27
. More recently, and therefore with fewer validation studies in general care settings, researchers have tested instruments as short as single items and as long as 80 items requiring scoring algorithms and keys for interpretation10,28
. One widely known brief screening tool, the CAGE questionnaire, while accurately identifying more severe unhealthy alcohol use (i.e. dependence), was not developed to detect risky consumption amounts or alcohol problems that are more amenable to brief interventions in primary care29
. The MAST similarly identifies alcohol dependence and is less well validated for detecting risky use and at 25 items (or 10 items for a briefer version) does not present advantages in length25
. The 10-item AUDIT, although well-validated for detecting risky drinking, is less well known or used by primary care physicians, likely in part because it requires scoring and it is not easily memorized for incorporation into the medical interview. The AUDIT and ASSIST may have promise as electronic record systems with decision support become more widespread (and as evidence for the validity of the ASSIST accumulates). The ASSIST has one other major limitation — it does not directly identify risky consumption amounts. The single-question screen proposed by Williams et al. is not identical to that recommended by the NIAAA but it too has proven to be accurate for identifying unhealthy alcohol use among emergency department patients, in primary care, and among respondents to a household survey9,10,12
. In summary, in terms of brevity, ease of scoring, and validity for detecting the conditions of interest in primary care, and therefore, likely greater ease for widespread implementation as recommended by practice guidelines, the single item recommended by NIAAA appears to have favorable characteristics.
The results we report are similar to those from studies using different populations and different formulations of the single-question alcohol screen. This study adds to existing literature by validating the version recommended by the NIAAA in a sample of primary care patients — one of the main populations in which it was intended to be used. This version of the single-question screen was derived from a national household survey on alcohol use, the results of which were reported by Dawson, et al.15
. While they did not report test characteristics, and although the subjects were not primary care patients, analysis of their published results yields a sensitivity of 89.8% and a specificity of 68.3% for the detection of a current alcohol use disorder, results which were very close to those reported in the current study. In addition to being recommended for widespread use by a health authority, the question phrasing normalizes drinking of large amounts likely increasing honesty in replies, and it directly queries amounts that are defined as risky by national guidelines. The similar single-question screen proposed by Williams et al. that used different cut-off values (‘When was the last time you had more than X drinks in 1 day,’ with X
4 for women and 5 for men, and a response of less than 3 months ago considered a positive screen) yielded sensitivities of between 80% and 85% and specificities of between 70% and 77% for the detection of unhealthy alcohol use, and was validated in a sample of primary care patients by Seale, et al.10,12
. A third formulation of the single-question screen, using the third question of the AUDIT and its multiple response options (‘How often in the last year have you had 6 or more drinks on one occasion’ with a response other than ‘never’ considered a positive screen), had a sensitivity of 77% and a specificity of 83% for the detection of unhealthy alcohol use in a sample of male veteran primary care patients, though the sensitivity was lower in a separate study of female veterans (both findings confirmed in subsequent studies of non-veterans)11,13,20,21
. These comparisons suggest that using slightly different cut-offs or changing the phrasing of the question affects the test characteristics to only a small degree.
In order for a screening test for unhealthy alcohol use to be useful, it must be applicable to the broad range of people seen in primary care. The diversity of our subject sample allowed us to examine the effect of gender, ethnicity, primary language and education on the accuracy of the single-question screen. While variations were seen in the sensitivity and specificity of the test across these groups, the differences were small. The single-question screen performed well in an urban, predominately minority population, a population different from those in which single-question screens had been tested previously. This, taken together with the results of the other studies, conducted in a number of different settings, of the other single-question screens that similarly ask about heavy drinking, lends strong support to their use.
Our study has several limitations. Almost half of the patients approached in the primary care waiting room refused to be screened for eligibility in the study, and approximately one fourth of eligible subjects did not complete the study. A lack of information about those who did not participate raises the possibility that those studied were not representative of primary care patients, potentially limiting the generalizability of our results. A higher than expected proportion of subjects reported substance use disorders, likely reflecting the fact that they were recruited from an urban safety-net hospital located in a community where the prevalence of such problems is high, but potentially also reflecting selection bias. The evaluation of a test in an atypical population can result in spectrum bias if, for instance, the unusual severity of the condition renders it more or less easily detectable. While the very close approximation of our results to those of this question and similar questions in other settings suggests that such bias, if present, is small, further study of the question’s test characteristics in a more affluent, lower-risk population may be justified. A limitation of the NIAAA recommended question, and, as far as we know, of the other single-question screens, is that they have not yet been validated languages other than English. This represents another potential future area of study. Subjects were also assured anonymity, a condition which improves the accuracy of the reference standard interview but which may also serve to over-estimate the accuracy of the screening test itself. This is consistent, however, with the methodology of most other alcohol screening test studies.
The single-question screen accurately identified subjects with unhealthy alcohol use. Some patients who screen positive will have severe alcohol use disorders requiring referral to substance abuse treatment, while those who consume excessive amounts of alcohol but have not experienced severe health or interpersonal problems would benefit from brief intervention by the primary care provider. The lack of an efficient way to distinguish these two groups (the NIAAA Clinician’s Guide recommends following up a positive screening test with 13 questions about drinking amounts and alcohol problems), is a challenge that must be addressed when implementing screening for unhealthy alcohol use. The AUDIT and ASSIST, in providing scores, provide a measure of severity. Even though they may be too long for universal screening in many settings, they might be done as brief assessments after a single-item screening question is answered in the affirmative. But this approach has not been tested or validated. Vinson et al. found that two follow-up questions (about drinking in hazardous situations and drinking more or for longer than intended) could identify alcohol use disorders among those with a positive response to a single-question screen30
. This approach, if validated, might represent a more efficient solution than applying a longer test to all patients.
The single-question screen recommended by the NIAAA accurately identified unhealthy alcohol use in this sample of primary care patients. The sensitivity and specificity of this single question was comparable to that reported for longer instruments in other studies. These findings of validity support the use of this brief screen in primary care as recommended by NIAAA, which should, in turn, help with the implementation of universal screening for unhealthy alcohol use as recommended by national practice guidelines.