Development and a Pilot Randomized Controlled Trial of a Brief Alcohol Intervention During Smoking Cessation Treatment Delivered by Healthcare Professionals

Co-use of Alcohol and Tobacco Co-use of tobacco and alcohol is common globally. Positive association of smoking and drinking at individual level has been found in both community settings and psychiatric epidemiological studies. In the U.S (2001-2002), about 21.7% of current drinkers were also current smokers, and about 34.8% of current smokers were current drinkers. In Hong Kong, according to the population-based study conducted by Hong Kong Council on Smoking and Health in 2018, about 22.2% and 9.3% of current smokers drank at least once a week and drank alcohol daily, respectively. From the client data (2014-16) of Tung Wah Group of Hospitals Integrated Centre on Smoking Cessation (TWGH-ICSC), the largest cessation service provider in Hong Kong, the prevalence of lower-risk drinking, increasing risk drinking, harmful drinking, and probable alcohol dependence, screened by the Alcohol Use Disorders Identification Test (AUDIT). in their clients is about 46.7%, 10.9%, 2.7% and 2.4%, respectively.

Co-use of tobacco and alcohol is harmful and incur substantial economic loss. Both tobacco and alcohol were classified by World Health Organization (WHO) as a Group 1 carcinogens. Concurrent use of tobacco and alcohol leads to 25.3% mortality due to coronary heart disease, stroke, respiratory and smoking-related cancer, compared with 20.5% among people who only smoked and 12.8% among who only had 15+ units of alcohol each week. Co-use of alcohol and tobacco also poses a severe economic burden on family and community. According to the Lancet's 2017 study, tobacco use costs global economies more than US$1 trillion annually through loss of productivity and health-care expenditure, while the weighted average cost of alcohol consumption ranged from 0.45 and 5.44% of Gross domestic Product (GDP)purchasing power parity (PPP) globally.

How Alcohol Use Hinders Smoking Cessation Alcohol consumption hinders smoking cessation, which can be explained by the theory in subjective reward effects, cross-substance cue reactivity, and other psychosocial factors. Based on the subjective reward effects, alcohol consumption increases nicotine's subjective rewarding effects, and hence increases satisfaction, liking, and calming feelings due to nicotine. Therefore, attempts to quit smoking are less successful among those with alcohol use disorder. The cross-substance cue reactivity suggested that there are cognitive or semantic associations between alcohol and cigarette use. That is, one substance will cue the use of the other substance. When alcohol and tobacco are used together for a number of times, the use of either substance will trigger a craving of another substance. This theory was commonly used to explain why alcohol is always an obstacle in smoking cessation and a cue for smoking relapse. These mechanisms have been supported by intervention trials and observational studies, showing that smoking rates among drinkers of different levels were significantly higher compared with non-drinkers after receiving smoking cessation treatment. If health care professionals (HCPs) do not handle smokers' drinking problems, they may miss the opportunity to help smokers to tackle the drinking problems at the same time.

Local Findings From the 2014-16 record of TWGH-ICSC, the self-reported quit rate at 26-week for clients with baseline AUDIT score 1-8, 9-15, and ≥16 after receiving the standard smoking cessation treatment was 43.4% (95% Confidence Interval (CI) 41.8%-45.1%), 37.1% (95%CI 33.8%-40.5%) and 26.7% (95%CI 22.4%-31.4%), respectively. The 52-week quit rate in these three drinking groups showed similar contrast (AUDIT score 1-8: 38.7%, 95%CI 37.0%-40.3%; 9-15: 31.9%, 95%CI 28.7%-35.2%; ≥16: 21.6%, 95%CI 17.7%-26.1%). Therefore, higher alcohol dependence is associated with lower abstinence in quit attempters who receive smoking cessation treatment. Two participants who self-reported tobacco abstinence for over a month from our ongoing qualitative study (funded by Health and Medical Research Fund (HMRF), ref no. 15163001) of smoking cessation stated that they were only smoking when they were drinking alcohol. They expressed that they smoked whenever they were drinking with friends and did not perceive occasional smoking during drinking episode as smoking relapse. All these results suggested that alcohol use reduces the effectiveness of smoking cessation treatment.

Interventions for Smoking and Drinking Co-use The above literature review suggested that a smoking cessation treatment that simultaneously addresses both alcohol and smoking problems is needed in clinical practice. The U.S. clinical practice guideline of treating tobacco use and dependence mentioned that helping smokers to recognize the dangerous situations of alcohol use is essential, and HCPs should instruct smokers to reduce/abstain from alcohol while quitting smoking. Previous study in alcohol treatment showed that alcohol users generally accept a concurrent treatment of both smoking cessation and alcohol.Combination of pharmacotherapy (i.e. varenicline and naltrexone) has been recommended to effectively and simultaneously treat heavy alcohol use and nicotine dependence.