To determine the benefit or harm of a new therapy, ideally, randomized controlled trials are usually conducted, a "gold standard" trial, as it is often called. In such a trial, one group, called the treatment group of people are exposed to the treatment and another similar group, the control group is not. After some months or years have elapsed, mortality and morbidity in the two groups is compared. In the case of smoking cessation trials, the measures focus on rate of successful withdrawal, length of time in withdrawal and relapses.
There are many people and organizations touting what are claimed to be effective methods of helping smokers to stop. Such claims of success are rarely backed up by independent comparative clinical trials or correctly calculated success rates. A separate thorough review of the evidence for each of several methods and aids for stopping smoking is available via the Cochrane Library website.[1]
Many such trials have been conducted to determine the health effects of quitting smoking although most have used quitting plus other lifestyle changes in diet and exercise, with or without drugs to improve blood pressure and blood cholesterol. The Cochrane Collaboration [2] have examined these trials and concluded that such interventions do not improve life expectancy or the death rate due to heart disease. They conclude that "Contrary to expectations, these lifestyle changes had little or no impact on the risk of heart attack or death" and "The continued enthusiasm for health promotion practices given the failure of these community intervention trials is curious, especially given the huge resources which have been put into them."
A U.S government study of smoking cessation research was published in 2000 called “Clinical Practice Guideline: Treating Tobacco Use and Dependence” [3] This was updated in 2008 in the publication "Clinical Practice Guideline: Treating Tobacco Use and Dependence: 2008 Update" [4] (to be called here the "Clinical Practice Guideline", or "2008 update" or simply "Guideline" report). Experts screened over 8700 research articles published between 1975 and 2007. More than 300 studies passed the criteria for the gold standard trials. Using these 300 studies for a meta-analysis of relevant treatments, it gives advice on smoking cessation treatment. An additional 600 reports were not included in the meta-analysis, but helped formulate the recommendations.
In general: a) Control groups quit at a rate of around 10%. b) Pharmacological treatments resulted in 15-33% quit rates. d) Psychosocial interventions resulted in 14-25% quit rates. e? Little or no evidence was found to support use of alternate medicine or cigarette substitutes.
For the meta-analysis, The Clinical Practice Guideline used percent of subjects who were not smoking at a follow-up 5–6 months after the start of the study as their common measure of success. The authors state that this measure is representative of successful cessations. Most relapses occur before this time and longer term measures are generally comparable to this measure. (See chapter 1, section Outcome Data for a further discussion). Comparisons between treatment group and control group measures is expressed as the ratio of the treatment group scores divided by the control group scores. (see chapter 1, section on Meta-Analytic Techniques for a further discussion). The report includes tables setting forth percentage of subjects abstaining from smoking at the 6 month follow-up ("quit rates") and success rates for various treatments relative to control groups. Some of the statistically significant results are listed below (reported in chapter 6 of the Guideline report).
The following results are shown in Table 6.26 comparing placebo effect to pharmacological treatments.
Not reported in the Guideline, several studies have found that smoking cessation advice is not always given in primary care in patients aged 65 and older,[5][6] despite the significant health benefits which can ensue in the older population.[7]
(1) Contact of 3 to 10 minutes can increase quit rate 60%. (Table 6.8) (2) Cessation programs involving more than 30 minutes of contact time increased success rates over no contact (11%) as much as 2 to almost 3 times (26% to 38.4%), regardless of other quitting method included (Table 6.9) (3) Number of Sessions: Programs involving 8 or more treatment sessions can double success rates (24%) over 0 or 1 session (12%). (Table 6.10)
The Guideline report from 2000 showed significant results for two methods. However, the Guideline 2008 update indicates that these methods may not be as effective as shown in 2000. The two methods are given a lower "Strength of Evidence" rating in the 2008 Guideline. These methods are as follows:
Ten other formats of intervention are not recommended. See Chapter 6, section 3. Treatment Elements for further explanation.
The authors indicate that there is no adequate evidence to support the use of hypnosis, acupuncture, or laser therapy as treatments for smoking cessation. No research meeting the required "Gold Standard" criteria was reported on use of cigarette substitutes.