A comparison of the efficacy of brief interventions to reduce hazardous and harmful alcohol consumption between European and non-European countries: a systematic review and meta-analysis of randomised controlled trials

AIMS: The extent of variation attributable to regional differences for the efficacy of brief intervention (BI) to reduce hazardous and harmful alcohol consumption is unclear. The primary aim of this study was to determine overall efficacy of BI at 6 and 12 month follow-up in primary health care (PHC) and emergency department (ED) studies. The secondary aim was to examine whether variance in study outcome can be explained by the geographical region in which trials have taken place (European versus non-European).

METHODS: A systematic review and meta-analysis of randomised controlled trials (RCTs) published before August 2014 was undertaken. Twenty RCTs conducted in PHC settings with a total of 8226 participants (European=4564/non-European=3662) and eight RCTs conducted in ED settings with a total of 4799 participants (European=2465/non-European=2334) were eligible. Primary outcome measure was reduction in grams of alcohol consumed per week for BI and control groups at 6 and 12 month follow-up. An inverse variance model was applied to measure the effect of treatment in mean differences for BI and control groups at 6 and 12 month follow-up. Variance between study outcomes was explored using sub-group analysis of European versus non-European countries.

RESULTS: For PHC trials at 6 month follow-up, statistically significant benefits of BI were indicated (Mean Difference (MD)=-21.98 grams/week; 95% Confidence Interval (CI)=-37.40 to -6.57; p=0.005). At 12 month follow-up, statistically significant benefit of BI was evident (MD=-30.86 g/w; 95% CI=-46.49 to -15.23; p= 0.0001). For ED trials at 6 month follow-up, statistically significant benefits of BI were indicated (MD=-17.97 g/w; 95% CI=-29.69 to -6.24; p=0.003). At 12 month follow-up, statistically significant benefit in favour of BI was evident (MD=-18.21 g/w; 95% CI=-26.71 to -9.70; p<0.0001). No statistically significant differences were detected in subgroup analyses of outcomes for European versus non-European studies.

CONCLUSIONS: Brief intervention (BI) to reduce alcohol consumption is associated with reducing grams of alcohol consumed per week amongst hazardous and harmful drinkers at 6 and 12 month follow-up in primary health care and emergency department trials. The geographical region in which trials are undertaken does not appear to explain variance in trial outcomes for reducing alcohol consumption.