COMPREHENSIVE REVIEW Predictors of study setting (primary care vs. hospital setting) among studies of the effectiveness of brief interventions among heavy alcohol users: A systematic review NOREEN DADIRAI MDEGE 1 & JUDITH WATSON 1,2 1 Addiction Research Group, Department of Health Sciences, University ofYork, York, UK, and 2 York Trials Unit, Department of Health Sciences, University ofYork, York, UK Abstract Issues. The aim of this study is to compare studies by their setting in order to identify design differences between studies on brief interventions (BI) for heavy alcohol use conducted in primary care and those in hospital settings. Approach. Potential studies were extracted from 16 reviews and from systematically searching literature up to October 2011.We assessed whether the following factors were statistically significant predictors of study setting: exclusion of very heavy/dependent drinkers; mean age of study sample; gender composition of study samples; sample size; total intervention delivery time; number of sessions; interventionist (physician vs. non-physician); various study design and intervention fidelity aspects; accounting for screening/ assessment reactivity; and control condition utilised. Key Findings. Seventy-six studies (30 in primary care and 46 in hospital settings) met the inclusion criteria.The following factors were statistically significant predictors of study setting: number of sessions {odds ratio [OR] = 0.281 [95% confidence interval (CI) 0.081, 0.979; P = 0.046]}, exclusion of very heavy/ dependent drinkers [OR = 0.052 (95% CI 0.004, 0.716, P = 0.027)] and gender composition of study samples [OR = 1.063 (95% CI 1.005, 1.125; P = 0.033)]. Implications. Researchers developing hospital setting BIs for excessive alcohol consumption should take into account methodological issues that could explain differences in the consistency of findings between hospital setting studies and primary care setting studies where BIs have been more consistently found effective in reducing alcohol use. Conclusion. The observed study design differences between hospital and primary care settings might partly explain the disparity in the consistency of findings on effectiveness of BIs between these settings. [Mdege ND, Watson J. Predictors of study setting (primary care vs. hospital setting) among studies of the effectiveness of brief interventions among heavy alcohol users: A systematic review. Drug Alcohol Rev 2013] Key words: brief intervention, primary care, hospital, effectiveness, systematic review. Introduction Opportunistic screening and brief interventions (BI) have been more consistently found effective in reducing alcohol use in patients with excessive alcohol consump- tion in primary care settings than in hospital settings. As a result, systematic reviews have concluded that BIs are effective in reducing alcohol use in patients with excessive alcohol consumption in primary care settings [1–3], whereas most systematic reviews of studies con- ducted in hospital settings have reported inconclusive findings [4–6]. BIs have therefore been advocated as part of population alcohol strategies in primary care settings [7]. On the other hand, it is unclear whether they should be encouraged in hospital settings even though these settings provide an opportunity to engage with heavy drinkers [8], especially those who might not be well represented in primary care settings such as men [9,10]. Some differences in the consistency of outcomes between these settings in general could indeed be due to the contextual differences in the loca- tions from which patients are identified, interventions Noreen Dadirai Mdege MPH, Research Fellow, Judith Watson DPhil, Research Fellow. Correspondence to Ms Noreen Dadirai Mdege, Department of Health Sciences, University of York, Heslington,York YO10 5DD, UK. Tel: +44 (0) 1904 321836; Fax: +44 (0) 1904 321387; E-mail: noreen.mdege@york.ac.uk Received 21 August 2012; accepted for publication 5 February 2013. REVIEW Drug and Alcohol Review (2013) DOI: 10.1111/dar.12036 © 2013 Australasian Professional Society on Alcohol and other Drugs