Validation of the AUDIT-C in adults seeking help with their drinking online

Early identification of people drinking at risky levels followed by brief intervention is the key individual-level intervention approach for reducing alcohol intake to safer levels [1, 2], with efficacy demonstrated in a range of settings including primary care, emergency departments, higher education and the workplace [3–8]. From the 1980s onwards the World Health Organisation (WHO) developed the Alcohol Use Disorders Identification Test (AUDIT), a 10-item screening questionnaire for detecting hazardous, harmful and dependent drinking in primary care [9]. There is now a substantial literature demonstrating the validity of the AUDIT in settings beyond primary care, such as inpatient hospital wards, emergency departments, universities, workplaces, outpatient settings and psychiatric services [10]. Above the basic threshold score of 8, the AUDIT guidance offers cut-off scores that indicate the severity of a person’s drinking, which in turn can be matched to the help they require, i.e. simple advice (score 8–15), simple advice plus brief counselling and continued monitoring (score 16–19), or referral to a specialist for assessment and treatment (score 20–40) [9]. These higher cut-offs are based on expert opinion rather than validation data.

Since the development of the AUDIT there have been a number of abbreviated versions that allow screening to take place in busy environments where time is limited [11]. The AUDIT-C is an abbreviated version of the AUDIT that has been advocated for use in both research and practice settings where there is insufficient time to administer the full AUDIT [11]. It consists of the first three questions of the AUDIT that relate to alcohol intake, where ‘C’ indicates ‘Consumption’ [12]. The AUDIT-C demonstrates similar accuracy to the full AUDIT [13, 14], however, the cut-off scores used to identify risky drinking, i.e. consumption above recommended limits, have varied in previous studies.

In 2007, a review of abbreviated versions of the AUDIT recommended an AUDIT-C cut-off score of ?3 (women) and ?4 (men) for detecting hazardous or harmful drinking [13]. This recommendation was based on a narrative review of 10 studies, of which four were in primary care patients, two in veteran populations, two in the general population [15, 16], one in hospitalised patients and one in psychiatric patients. Two studies included in this review found ‘optimal’ AUDIT-C scores (defined as those that maximise the sum of sensitivity and specificity) for detecting drinking above recommended limits in the general population of ?5 in Germany [15] and ?5 (men) and ?3 (women) in the US [16]. Another review published the following year, identified four studies that tested the accuracy (i.e. the highest overall proportion of true positives and false negatives) of the AUDIT-C in detecting risky drinking in European general population samples, with cut-off scores of ?5 and ?6 [15, 17–19], where prevalence ranged from 5 to 37% [14]. Surprisingly few studies published since these reviews have validated the AUDIT-C in general population samples. One recently published study based in the adult general population in Sweden found the ‘optimal’ AUDIT-C cut-off score for detecting drinking above recommended limits (termed “risk drinking”) was ?6 (men) and ?4 (women) [20]. The AUDIT-C has not been validated for identifying risky drinking in adults from the United Kingdom.

There may be many reasons for the heterogeneity in findings in previous studies including differences in populations, settings and cultures, where both prevalence and recommended drinking limits vary. Validation studies use different reference standards and forms of measurement for determining hazardous or harmful drinking, e.g. time-line follow-back, 10-item AUDIT, International Classification of Diseases (ICD-10 criteria) and the Diagnostic and Statistical Manual of Mental Disorders (DSM-III-R, DSM-IV) [13, 14]. There are also differences in the type of cut-off scores selected, depending on the use to which the test is put.

Screening and brief intervention delivered over the Internet has grown in popularity over the past decade and is now a substantial field of research [21]. Electronic screening enables instantaneous data collection and eliminates the need for manual data entry, thereby reducing errors that this process may introduce. Alcohol screening tests, which are conventionally delivered in-person or in paper-based format, appear to retain their psychometric properties when delivered online [22–26]. There is also some evidence that being self-administered, online screening is likely to generate more honest reporting of risky alcohol use, in comparison with a face-to-face interview [27, 28]. The AUDIT-C has been used to screen for eligibility in two trials of web-based alcohol screening and brief intervention delivered to students in New Zealand (?4 for men and women) [29, 30] and two trials of facilitated access to an online intervention delivered in primary care in Italy and Spain (?5 for men and ?4 women) [31, 32]. These trials did not validate the AUDIT-C for use online, and were not conducted in general population samples.

The purpose of this study was to determine a suitable cut-off score for the AUDIT-C for identifying risky drinkers in a general population sample of people seeking online help with their drinking. Objectives were to determine the sensitivity, specificity, likelihood ratios and area under the Receiver-operating characteristic (ROC) curves of different cut-off scores for the AUDIT-C, with a goal of identifying people drinking above the recommended UK weekly consumption limits. To the best of our knowledge, this is the first study that seeks to validate the AUDIT-C in a population of people seeking help with their drinking over the Internet.