Introduction
Smoking is one of the main risk factors for many chronic diseases, and it is still the main preventable cause of disease and premature death in the world. It is of great significance to implement smoking cessation treatment for all smokers. Nicotine contained in tobacco products can trigger the release of dopamine and other neurotransmitters in the brain, thereby enhancing smokers’ dependence on tobacco. 1 However, smoking is an addictive behavior, for most smokers, it is difficult for them to quit smoking permanently. In a survey of more than 5000 adults in England in 2006, about half of smokers have tried to quit smoking at least once in the past year, and it is estimated that there is a permanent smoking cessation rate of 2% to 3% every year. 2
For smokers with alcohol problems, they face greater health risks and it is more difficult to quit smoking. Globally, the disability adjusted life years of tobacco and alcohol use rank fourth and fourth and fifth respectively. 3 The co-occurrence of smoking and drinking is a significant public health concern, tobacco use and alcohol use disorder have a high prevalence of comorbidities. Smoking combined with alcohol use has negative health effects, including but not limited to increased cancer risk and mortality. 4-6Epidemiological studies show that there is a strong positive correlation between smoking and drinking. 3,7 For example, a study published in 2006 investigated cigarette smoking and the risk for alcohol use disorders among adolescent drinkers, and the results showed that smokers had 4.5-fold higher odds of alcohol use disorders than never-smokers. 8 Compared with people who do not drink alcohol, alcoholics have a higher smoking rate. 9-11For example, Elissa R. et al. conducted a survey in US colleges, and the most obvious finding is that 44-59% of alcoholic drinkers smoke.12 And clinical trials have shown that drinking after quitting smoking will promote the recurrence of smoking.13 It can be seen that it may be more difficult for smokers who use alcohol to quit smoking. Therefore, smoking cessation treatment for alcoholics can not only improve the success rate of smoking cessation, but also reduce the cost of medical care.
Drug therapy is the most common way to quit smoking. Randomized controlled trials (RCTs) are widely acknowledged as the design of choice for evaluating the effectiveness of health care. 14,15Many clinical trials and systematic reviews have revealed the effectiveness of some drugs in smoking cessation. In order to verify the effectiveness of different drugs on alcoholic smokers, a network meta-analysis is conducted in this study. At present, there are some clinical trials on smoking cessation of alcoholic smokers with different drug treatments. The existing traditional systematic review can only compare the effects of experimental drugs and control treatment. The purpose of this network meta-analysis is to directly or indirectly compare the smoking cessation effects of a variety of different drugs on alcoholic smokers, so as to rank the smoking cessation effects of different drugs.