Abstract: We included in this updated review one new study (70 participants), resulting in a total of three RCTs (140 participants who drank 3 to 40 AU/d). All three studies were of moderate to good quality. All studies evaluated the effects of intensive alcohol cessation interventions, including pharmacological strategies for alcohol withdrawal symptoms, patient education, and relapse prophylaxis. We identified one ongoing study. Overall, 53 of the 122 participants from three studies who underwent surgery developed any type of postoperative complication that required treatment. Of 61 participants in the intervention groups, 20 had complications, compared with 33 of 61 participants in the control groups (risk ratio (RR) 0.62, 95% confidence interval (CI) 0.40 to 0.96). Results show differences between the three clinical studies regarding outcome measurement and intensity of the interventions. However, all alcohol cessation programmes were intensive and included pharmacological therapy. The overall quality of evidence for this outcome is moderate. In-hospital and 30-day postoperative mortality rates were low in the three studies. Researchers reported one death among 61 participants in the intervention groups, and three deaths among 61 participants in the control groups (RR 0.47, 95% CI 0.07 to 2.96). The quality of evidence for this outcome is low. Investigators describe more successful quitters at the end of the intervention programme than among controls. Forty-one out of 70 participants in the intervention groups successfully quit drinking compared with only five out of 70 participants in the control groups (RR 8.22, 95% CI 1.67 to 40.44). The quality of evidence for this outcome is moderate. All three studies reported postoperative alcohol consumption (grams of alcohol/week) at the end of the programme as median and range values; therefore it was not possible to estimate the mean and the standard deviation (SD). We performed no meta-analysis. All three studies reported length of stay, and none of these studies described a significant difference in length of stay. Data were insufficient for review authors to perform a meta-analysis. No studies reported on the prevalence of participants without risky drinking in the longer term. This systematic review assessed the efficacy of perioperative alcohol cessation interventions for postoperative complications and alcohol consumption. All three studies showed a significant reduction in the number of participants who quit drinking alcohol during the intervention period. Intensive alcohol cessation interventions offered for four to eight weeks to participants undergoing all types of surgical procedures to achieve complete alcohol cessation before surgery probably reduced the number of postoperative complications. Data were insufficient for review authors to assess their effects on postoperative mortality. No studies reported an effect on length of stay, and no studies addressed the prevalence of risky drinking in the longer term. Included studies were few and reported small sample sizes; therefore one should be careful about drawing firm conclusions based on these study results. All three studies were conducted in Denmark, and most participants were men. The included participants may represent a selective group, as they could have been more motivated and/or more interested in participating in clinical research or otherwise different, and effects may have been overestimated for both intervention and control groups in these studies. Trial results indicate that these studies are difficult to perform, that strong research competencies are necessary for future studies, and that further evaluation of perioperative alcohol cessation interventions in high-quality randomized controlled trials is needed. Once published and assessed, the one 'ongoing' study identified may alter the conclusions of this review.

Plain-language summary: We included three randomized controlled trials with a total of 140 participants. All three studies included participants with risky alcohol intake (3 to 40 AU daily) who were in need of surgery. These studies investigated intensive alcohol interventions aimed at complete alcohol cessation at the time of surgery compared with no intervention. Interventions included educational strategies for alcohol withdrawal and relapse prevention. Programmes were started three months before surgery, four weeks before surgery, and from the time of admission to surgery, and continued for six weeks after surgery, respectively. The quality of the evidence is of moderate to low quality. In all three studies, intensive intervention programmes clearly increased the number of participants who quit drinking alcohol. The occurrence of postoperative complications appeared to be reduced as well. Of 61 participants in the intervention groups, 20 had complications requiring treatment, compared with 33 of 61 participants in the control groups (moderate-quality evidence). Of 70 participants in the intervention groups, 41 successfully quit drinking, compared to five of 70 participants in the control groups (moderate-quality evidence). Data were insufficient to show the effect of quitting drinking on the number of deaths (low-quality evidence), and results show no effect on length of hospital stay. None of the included studies reported on the number of participants who continued to avoid risky drinking in the longer term (at three-, six-, nine-, and 12-month follow-up). Included studies were few and reported small sample sizes; therefore one should be careful about drawing firm conclusions based on these results. All three studies were conducted in Denmark, and most participants were men. The included participants may represent a selective group, as they could be more motivated and/or more interested in participating in clinical research or otherwise different, and effects may therefore have been overestimated for both intervention and control groups in these studies. More research is needed and new strategies are required to improve outcomes after surgery among risky drinkers.