Journal Club Alcohol and Health: Current Evidence July–August 2005

Featured Article Screening for hazardous or harmful drinking using one or two quantity-frequency questions Canagasaby A, Vinson DC. Alcohol Alcohol. 2005;40(3):208–213.

Study Objective To compare the performances of brief screening tests to detect unhealthy alcohol use

Study Design Investigators screened… –1537 emergency department patients with an acute injury, –1151 emergency patients with a medical illness –1112 randomly selected people contacted by telephone Researchers first asked each subject… –a question about alcohol consumption in a day (“When was the last time you had more than X drinks in 1 day?” with X being 5 for men and 4 for women)

Study Design (cont.) They asked subjects who reported drinking >=6 drinks in the past year 2 standard questions about quantity and frequency of consumption: –the average number of drinks per occasion –the frequency of drinking (5-point ordinal scale from “less than once a month” to “almost every day”) Diagnostic interviews (the Diagnostic Interview Schedule) determined the presence of an alcohol use disorder (based on the Diagnostic and Statistical Manual of Mental Disorders, DSM IV). Validated calendar methods determined drinking amounts.

Assessing Validity of an Article about Diagnostic Tests Are the results valid? What are the results? How can I apply the results to patient care?

Are the Results Valid? Did clinicians face diagnostic uncertainty? Was there a blind comparison with an independent gold standard applied similarly to the treatment group and the control group? Did the results of the test being evaluated influence the decision to perform the reference standard?

Did clinicians face diagnostic uncertainty? Because of the nature of screening (testing people regardless of symptoms of the target disorder), there was inherent diagnostic uncertainty. –Diagnoses were not known prior to testing.

Was there a blind comparison with an independent gold standard applied similarly to the treatment group and the control group? There was a comparison with a “gold” (reference) standard applied to all subjects. –The reference standard was a structured interview conducted by trained research staff. Staff was not blinded to the answers provided by subjects.

Did the results of the test being evaluated influence the decision to perform the reference standard? No: –Everyone completed the reference standard. –However, the diagnostic reference standard (though well-accepted and extensively validated) defines people who deny having had >=6 drinks in the past year as having no alcohol use diagnosis.

What Are the Results? What likelihood ratios were associated with the range of possible test results?

What likelihood ratios were associated with the range of possible test results? At a specificity of at least 70%, the single question about alcohol consumption in a day had the best sensitivity. A response of “in the last 3 months” was associated with the following likelihood ratios: –For women: positive test 3.6; negative test 0.2 –For men: positive test 2.8; negative test 0.2

How Can I Apply the Results to Patient Care? Will the reproducibility of the test result and its interpretation be satisfactory in my clinical setting? Are the results applicable to the patients in my practice? Will the results change my management strategy? Will patients be better off as a result of the test?

Will the reproducibility of the test result and its interpretation be satisfactory in my clinical setting? The interpretation is not difficult. Reproducibility is uncertain since the screening questions were asked by trained research staff. The question is not difficult to ask and training is not required; however, patients may be less forthcoming with their own caregivers.

Are the results applicable to the patients in my practice? The results appear to have broad applicability since screening occurred in emergency and general population samples.

Will the results change my management strategy? Results could change patient management. –Like previous studies, this study found that the single alcohol screening question has excellent sensitivity and specificity. –Current practice is to use questions that are not validated, or more rarely, to use 4- or 10-item validated screening questionnaires.

Will the results change my management strategy? (cont.) Use of a single screening question appears to be valid and much more likely to be employed in busy clinical practice. In a new guide for clinicians, the National Institute on Alcohol Abuse and Alcoholism recommends a similar single question for alcohol screening.

Will patients be better off as a result of the test? Yes; patients will benefit from this approach to screening. –Screening followed by brief intervention, when indicated, in primary care settings has proven efficacy for decreasing risky drinking in nondependent drinkers. –Patients identified by screening who have alcohol dependence may also benefit from referral to specialty treatment.

Summary/Clinical Resolution A single question asking about the last time a patient drank excessively can detect unhealthy alcohol use including risky drinking and alcohol use disorders. The only methodological caveat is that the full diagnostic reference standard used in this study was not completed in very light drinkers. –However, the caveat is a small one since it is unlikely that many people who report drinking <6 drinks per year would have unhealthy alcohol use.