Biomedical risk assessment as an aid for smoking cessation

Long-Term Consequences of Spirometry During Military Routine Medical Examinations on Smoking Cessation Compared to Minimal Advice

BACKGROUND

Smoking kills 8 million people a year worldwide. It is the most prevalent cause of death in France by cancer, cardiovascular, or respiratory diseases. Minimal advice consists in asking patients who smoke if they are interested in quitting. It is effective in reducing smoking. The French High Health Authority recommends its systematic use with patients, whatever their reason for seeking treatment. The beneficial effect of spirometry on smoking cessation is controversial. The objective of our study was to measure the consequences of spirometry associated with minimal advice, compared with only minimal advice in soldiers seen during a routine medical examination.

METHODS

Our prospective, longitudinal, open, multicenter, controlled, randomized study was conducted among French military smokers presenting for an occupational medicine visit. Each participant received, depending on their group (intervention or control), either minimal advice associated with an evaluation of lung function by mini-spirometer, or only minimal advice. Follow-up visits were performed at 6 and 12 months. The primary objective was self-reported tobacco use cessation at 6 months.

RESULTS

A total of 267 participants (126 in the intervention group and 141 for the control arm) were included in 10 centers between June 2019 and June 2020. The response rate was 75.6% at 6 months. The cessation rates were 17% and 18% in the intervention and control groups, respectively, with no significant difference between the two groups (P = 0.9). The cessation rate in the general population was 13% at 6 months.

CONCLUSIONS

Spirometry does not seem to influence smoke cessation on a military population at 6 months. The overall cessation rate in our study was well in excess of the 3-6% expected from only providing minimal which is underused in general practice and should be encouraged.

Interventions for tobacco use cessation in people living with HIV

BACKGROUND

The prevalence of tobacco use among people living with HIV (PLWH) is up to four times higher than in the general population. Unfortunately, tobacco use increases the risk of progression to AIDS and death. Individual- and group-level interventions, and system-change interventions that are effective in helping PLWH stop using tobacco can markedly improve the health and quality of life of this population. However, clear evidence to guide policy and practice is lacking, which hinders the integration of tobacco use cessation interventions into routine HIV care. This is an update of a review that was published in 2016. We include 11 new studies.

OBJECTIVES

To assess the benefits, harms and tolerability of interventions for tobacco use cessation among people living with HIV. To compare the benefits, harms and tolerability of interventions for tobacco use cessation that are tailored to the needs of people living with HIV with that of non-tailored cessation interventions.

SEARCH METHODS

We searched the Cochrane Tobacco Addiction Group's Specialised Register, CENTRAL, MEDLINE, Embase, and PsycINFO in December 2022.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) of individual-/group-level behavioural or pharmacological interventions, or both, for tobacco use cessation, delivered directly to PLWH aged 18 years and over, who use tobacco. We also included RCTs, quasi-RCTs, other non-randomised controlled studies (e.g. controlled before and after studies), and interrupted time series studies of system-change interventions for tobacco use cessation among PLWH. For system-change interventions, participants could be PLWH receiving care, or staff working in healthcare settings and providing care to PLWH; but studies where intervention delivery was by research personnel were excluded. For both individual-/group-level interventions, and system-change interventions, any comparator was eligible.

DATA COLLECTION AND ANALYSIS

We followed standard Cochrane methods, and used GRADE to assess certainty of the evidence. The primary measure of benefit was tobacco use cessation at a minimum of six months. Primary measures for harm were adverse events (AEs) and serious adverse events (SAEs). We also measured quit attempts or quit episodes, the receipt of a tobacco use cessation intervention, quality of life, HIV viral load, CD4 count, and the incidence of opportunistic infections.

MAIN RESULTS

We identified 17 studies (16 RCTs and one non-randomised study) with a total of 9959 participants; 11 studies are new to this update. Nine studies contributed to meta-analyses (2741 participants). Fifteen studies evaluated individual-/group-level interventions, and two evaluated system-change interventions. Twelve studies were from the USA, two from Switzerland, and there were single studies for France, Russia and South Africa. All studies focused on cigarette smoking cessation. All studies received funding from independent national- or institutional-level funding. Three studies received study medication free of charge from a pharmaceutical company. Of the 16 RCTs, three were at low risk of bias overall, five were at high risk, and eight were at unclear risk. Behavioural support or system-change interventions versus no or less intensive behavioural support Low-certainty evidence (7 studies, 2314 participants) did not demonstrate a clear benefit for tobacco use cessation rates in PLWH randomised to receive behavioural support compared with brief advice or no intervention: risk ratio (RR) 1.11, 95% confidence interval (CI) 0.87 to 1.42, with no evidence of heterogeneity. Abstinence at six months or more was 10% (n = 108/1121) in the control group and 11% (n = 127/1193) in the intervention group. There was no evidence of an effect on tobacco use cessation on system-change interventions: calling the quitline and transferring the call to the patient whilst they are still in hospital ('warm handoff') versus fax referral (RR 3.18, 95% CI 0.76 to 13.99; 1 study, 25 participants; very low-certainty evidence). None of the studies in this comparison assessed SAE. Pharmacological interventions versus placebo, no intervention, or another pharmacotherapy Moderate-certainty evidence (2 studies, 427 participants) suggested that varenicline may help more PLWH to quit smoking than placebo (RR 1.95, 95% CI 1.05 to 3.62) with no evidence of heterogeneity. Abstinence at six months or more was 7% (n = 14/215) in the placebo control group and 13% (n = 27/212) in the varenicline group. There was no evidence of intervention effects from individual studies on behavioural support plus nicotine replacement therapy (NRT) versus brief advice (RR 8.00, 95% CI 0.51 to 126.67; 15 participants; very low-certainty evidence), behavioural support plus NRT versus behavioural support alone (RR 1.47, 95% CI 0.92 to 2.36; 560 participants; low-certainty evidence), varenicline versus NRT (RR 0.93, 95% CI 0.48 to 1.83; 200 participants; very low-certainty evidence), and cytisine versus NRT (RR 1.18, 95% CI 0.66 to 2.11; 200 participants; very low-certainty evidence). Low-certainty evidence (2 studies, 427 participants) did not detect a difference between varenicline and placebo in the proportion of participants experiencing SAEs (8% (n = 17/212) versus 7% (n = 15/215), respectively; RR 1.14, 95% CI 0.58 to 2.22) with no evidence of heterogeneity. Low-certainty evidence from one study indicated similar SAE rates between behavioural support plus NRT and behavioural support only (1.8% (n = 5/279) versus 1.4% (n = 4/281), respectively; RR 1.26, 95% CI 0.34 to 4.64). No studies assessed SAEs for the following: behavioural support plus NRT versus brief advice; varenicline versus NRT and cytisine versus NRT.

AUTHORS' CONCLUSIONS

There is no clear evidence to support or refute the use of behavioural support over brief advice, one type of behavioural support over another, behavioural support plus NRT over behavioural support alone or brief advice, varenicline over NRT, or cytisine over NRT for tobacco use cessation for six months or more among PLWH. Nor is there clear evidence to support or refute the use of system-change interventions such as warm handoff over fax referral, to increase tobacco use cessation or receipt of cessation interventions among PLWH who use tobacco. However, the results must be considered in the context of the small number of studies included. Varenicline likely helps PLWH to quit smoking for six months or more compared to control. We did not find evidence of difference in SAE rates between varenicline and placebo, although the certainty of the evidence is low.

Case-Finding and Treatment Effects in COPD: Secondary Analysis of an Interdisciplinary Intervention Trial

Background

US Preventive Services Taskforce recommends against screening for COPD in asymptomatic adults due to limited evidence on the efficacy of treatments for this population. However, global and Australian guidelines recommend a case-finding approach where those with symptoms and/or risk factors, including smoking, are screened. This study aims to explore patient characteristics by time of COPD diagnosis and the effectiveness of early treatment in those with or without symptoms.

Methods

Secondary analysis of a randomised controlled trial that included those with a pre-existing (n=130) or new diagnosis (n=142) of COPD. Those randomised to the intervention arm received an interdisciplinary intervention of smoking cessation support, home medicines review and home-based pulmonary rehabilitation, while controls received usual care. The primary outcome was health-related quality of life (HR-QoL) measured using St George's Respiratory Questionnaire. To estimate the impact of early treatment, we compared the effectiveness of treatment versus control at 6- and 12-months for the new versus pre-existing diagnosis groups, and those symptomatic versus asymptomatic or minimally symptomatic based on COPD Assessment Test score.

Results

Approximately half of those newly diagnosed with COPD were already symptomatic. Early treatment in those diagnosed via case-finding had a positive non-significant impact on HR-QoL. The size of the treatment effects generally favoured the pre-existing diagnosis group when compared to case-finding and favoured those symptomatic when compared to those asymptomatic.

Conclusion

Despite useful insights into the impacts of case-finding and early treatments, this study, like most others, was not sufficiently powered. Further larger studies or combining sub-groups across studies are required.

Effectiveness of the spirometry-based motivational intervention to quit smoking: RESET randomised trial

BACKGROUND

The effectiveness of providing feedback on spirometry results for smoking cessation remains inconclusive according to the current evidence.

OBJECTIVES

To assess the effectiveness of a motivational intervention based on spirometry results in achieving prolonged smoking abstinence (12 months post-intervention).

DESIGN AND SETTING

A randomised, controlled, observer-blinded, multicentre clinical trial was conducted (from January 2012 to December 2015) in 20 primary healthcare centres in the Tarragona province, Spain.

METHODS

Participants, active smokers aged 35-70 without known respiratory disease, were recruited from primary healthcare centres by family doctors and nurses. They were randomly assigned to either the intervention group (IG = 308) or the control group (CG = 306). Both groups received brief smoking cessation counselling. Additionally, the IG underwent spirometry and received detailed information about the results, including lung age. The primary outcome was prolonged abstinence, defined as lasting at least 12 months and validated through cotinine measurement in urine.

RESULTS

The prolonged abstinence rate was 7.8% in the IG, compared to 2.6% in the CG (p = 0.004). At 12 months, in the multivariate analysis, the intervention was identified as an independent factor for smoking cessation (OR 2.8; 95%CI 1.2 to 7.7), a trend maintained throughout the follow-up (HR 2.74; 95%CI 1.13 to 6.62). Moreover, according to the Prochaska and DiClemente model, the preparation or action phase to quit was also associated with smoking cessation (HR 2.55, 95%CI 1.07 to 6.09).

CONCLUSION

A primary care-delivered intervention involving brief counselling and detailed spirometry information proves effective in increasing abstinence rates among active smokers without known respiratory disease. Additionally, smoking cessation is also influenced by the individual's stage of change.

TRIAL REGISTRATION

ClinicatTrials.gov NCT02153047.

Randomised controlled trial testing effectiveness of feedback about lung age or exhaled CO combined with very brief advice for smoking cessation compared to very brief advice alone in North Macedonia: findings from the Breathe Well group

INTRODUCTION

In 2019, smoking prevalence in North Macedonia was one of the world's highest at around 46% in adults. However, access to smoking cessation treatment is limited and no co-ordinated smoking cessation programmes are provided in primary care.

METHODS

We conducted a three parallel-armed randomised controlled trial (n = 1368) to investigate effectiveness and cost-effectiveness of lung age (LA) or exhaled carbon monoxide (CO) feedback combined with very brief advice (VBA) to prompt smoking cessation compared with VBA alone, delivered by GPs in primary care in North Macedonia. All participants who decided to attempt to quit smoking were advised about accessing smoking cessation medications and were also offered behavioural support as part of the "ACT" component of VBA. Participants were aged ≥ 35 years, smoked ≥ 10 cigarettes per day, were recruited from 31 GP practices regardless of motivation to quit and were randomised (1:1:1) using a sequence generated before the start of recruitment. The primary outcome was biochemically validated 7-day point prevalence abstinence at 4 weeks (wks). Participants and GPs were not blinded to allocation after randomisation, however outcome assessors were blind to treatment allocation.

RESULTS

There was no evidence of a difference in biochemically confirmed quitting between intervention and control at 4wks (VBA + LA RR 0.90 (97.5%CI: 0.35, 2.27); VBA + CO RR 1.04 (97.5%CI: 0.44, 2.44)), however the absolute number of quitters was small (VBA + LA 1.6%, VBA + CO 1.8%, VBA 1.8%). A similar lack of effect was observed at 12 and 26wks, apart from in the VBA + LA arm where the point estimate was significant but the confidence intervals were very wide. In both treatment arms, a larger proportion reported a reduction in cigarettes smoked per day at 4wks (VBA + LA 1.30 (1.10, 1.54); VBA + CO 1.23 (1.03, 1.49)) compared with VBA. The point estimates indicated a similar direction of effect at 12wks and 26wks, but differences were not statistically significant. Quantitative process measures indicated high fidelity to the intervention delivery protocols, but low uptake of behavioural and pharmacological support. VBA was the dominant intervention in the health economic analyses.

CONCLUSION

Overall, there was no evidence that adding LA or CO to VBA increased quit rates. However, a small effect cannot be ruled out as the proportion quitting was low and therefore estimates were imprecise. There was some evidence that participants in the intervention arms were more likely to reduce the amount smoked, at least in the short term. More research is needed to find effective ways to support quitting in settings like North Macedonia where a strong smoking culture persists.

TRIAL REGISTRATION

The trial was registered at http://www.isrctn.com (ISRCTN54228638) on the 07/09/2018.

Co-development of an evidence-based personalised smoking cessation intervention for use in a lung cancer screening context

BACKGROUND

Optimising smoking cessation services within a low radiation-dose computed tomography (LDCT) lung cancer screening programme has the potential to improve cost-effectiveness and overall efficacy of the programme. However, evidence on the optimal design and integration of cessation services is limited. We co-developed a personalised cessation and relapse prevention intervention incorporating medical imaging collected during lung cancer screening. The intervention is designed to initiate and support quit attempts among smokers attending screening as part of the Yorkshire Enhanced Stop Smoking study (YESS: ISRCTN63825779). Patients and public were involved in the development of an intervention designed to meet the needs of the target population.

METHODS

An iterative co-development approach was used. Eight members of the public with a history of smoking completed an online survey to inform the visual presentation of risk information in subsequent focus groups for acceptability testing. Three focus groups (n = 13) were conducted in deprived areas of Yorkshire and South Wales with members of the public who were current smokers or recent quitters (within the last year). Exemplar images of the heart and lungs acquired by LDCT, absolute and relative lung cancer risk, and lung age were shown. Data were analysed thematically, and discussed in stakeholder workshops. Draft versions of the intervention were developed, underpinned by the Extended Parallel Processing Model to increase self-efficacy and response-efficacy. The intervention was further refined in a second stakeholder workshop with a patient panel.

RESULTS

Individual LDCT scan images of the lungs and heart, in conjunction with artistic impressions to facilitate interpretation, were considered by public participants to be most impactful in prompting cessation. Public participants thought it important to have a trained practitioner guiding them through the intervention and emphasising the short-term benefits of quitting. Presentation of absolute and relative risk of lung cancer and lung age were considered highly demotivating due to reinforcement of fatalistic beliefs.

CONCLUSION

An acceptable personalised intervention booklet utilising LDCT scan images has been developed for delivery by a trained smoking cessation practitioner. Our findings highlight the benefit of co-development during intervention development and the need for further evaluation of effectiveness.

Spirometry and Smoking Cessation in Primary Care: The ESPIROTAB STUDY, A Randomized Clinical Trial

This study aims to evaluate the effect of regularly reporting spirometry results during smoking cessation counseling from a primary care physician on the quit rate in adult smokers.

METHODS

A randomized, two-arm intervention study was conducted at six primary care centers. A total of 350 smokers, ≥18 years of age, who consulted their primary care physician, participated in the study. At the selection visit, smokers who gave their consent to participate underwent spirometry. Subsequently, an appointment (visit 0) was scheduled to complete a nicotine dependence test, a smoking cessation motivation questionnaire, and a sociodemographic questionnaire. Participants were also offered brief, structured advice on how to quit smoking, as well as detailed information on spirometry results. Patients were then randomized and scheduled for follow-up visits at 3, 6, 12, and 24 months. Both arms received brief, structured advice and detailed information on spirometry results at visit 0. At consecutive follow-up visits, the control group only received brief, structured smoking cessation advice, while the intervention group also received information on initial spirometry results at visits 3 and 6, and a spirometry retest at visit 12. Exhaled carbon monoxide testing was used to check smoking cessation.

RESULTS

The study included 350 smokers; 179 were assigned to the control group and 171 to the intervention group. Smoking cessation at one year was 24.0% in the intervention group compared to 16.2% in the control group. At two years, it was 25.2% in the intervention group and 18.4% in the control group. Overall, the adjusted odds of quitting smoking in the intervention group were 42% higher than in the control group (p = 0.018).

CONCLUSIONS

Regular and detailed feedback of spirometry results with smokers increases smoking cessation. Specifically, the likelihood of quitting smoking in the intervention group is 1.42 times higher than in the control group (p = 0.018).

210Po and 210Pb content in the smoke of Heated Tobacco Products versus Conventional Cigarette smoking

210Po is a radioactive component of conventional cigarette tobacco smoke and is a recognized carcinogen. Despite the expanding market of heated tobacco products, no data are available on the activity of 210Po in the smoke of IQOS Heets cigarette. We determined the 210Po activity in the mainstream smoke of thirteen cigarette brands available on the Swiss market using a smoking machine and compared the results to the 210Po activity measured in the mainstream smoke of the IQOS system. In addition, we measured the 210Po and 210Pb loss on heating after uniform heating from 50 to 600 °C for several cigarette brands and the Heets cigarettes. 13.6 ± 4.1% of 210Po activity was found in the mainstream smoke in conventional cigarette smoking (7% for 210Pb). This dropped to 1.8 ± 0.3% in the mainstream smoke of IQOS Heets. Conversely, when the tobacco was heated uniformly at 330 °C, a loss of 210Po of more than 80% was observed for all type of cigarettes. Apparently, IQOS significantly reduced the 210Po and 210Pb activities in the mainstream smoke. However, our results show that only 15% of the Heets tobacco reaches 330 °C with IQOS. While IQOS reduces the 210Po and 210Pb activities in the mainstream smoke compared to conventional cigarettes, it only heats a marginal fraction of the tobacco present in the Heets cigarette. Because smoking is an addiction (mostly due to nicotine), IQOS could possibly deliver an unsatisfactory dose of nicotine to a Heets cigarette smoker, as most of the tobacco is left unaltered.

The effect of biofeedback on smoking cessation-a systematic short review

Purpose

The aim of this systematic review was to focus on the effect of biofeedback on smoking cessation.

Material and methods

This review was conducted following the PRISMA guidelines. Peer-reviewed original articles including biofeedback and/or neurofeedback training as an intervention for smoking cessation were included. The PubMed, MEDLINE, Web of Science, Scopus, and Cochrane Library databases were screened for trials published up to July 2021. The effects on smoking rates and smoking behavior, and biofeedback/neurofeedback training measures are summarized here.

Results

In total, three articles fulfilled the inclusion criteria. The total Downs and Black checklist scores ranged from 11 to 23 points, showing that the articles were of poor to good methodological quality. The included studies were heterogeneous, both in terms of treatment protocols and in terms of outcome parameters. Pooling of data for a meta-analysis was not possible. Therefore, we were limited to describing the included studies. The included biofeedback study demonstrated that skin temperature training might improve the patients’ ability to raise their skin temperature aiming at stress alleviation. All three studies reported positive effects of biofeedback/neurofeedback in supporting smokers to quit. Furthermore, individualized electroencephalography neurofeedback training showed promising results in one study in modulating craving-related responses.

Conclusion

The results of the present review suggest that biofeedback/neurofeedback training might facilitate smoking cessation by changing behavioral outcomes. Although the investigated studies contained heterogeneous methodologies, they showed interesting approaches that could be further investigated and elaborated. To improve the scientific evidence, prospective randomized controlled trials are needed to investigate biofeedback/neurofeedback in clinical settings for smoking cessation.

Self-Reported Smoking Status 10-Months After a Single Session Intervention Including an Education Conference About Smoking Harms and Announcement of Spirometric Lung-Age

Background

Studies investigating the effects of announcing spirometric lung-age (SLA) on the smokers' self-reported smoking status reported conflicting results.

Main objective

To evaluate the effects of a single session intervention including an education conference about smoking harms and announcement of SLA on the participants' self-reported smoking status.

Methodology

An interventional study was conducted in a cable factory. The intervention included four steps: PowerPoint presentation about raising smoking hazards awareness; general questionnaire; measurement of the anthropometric and spirometric data, and announcement of SLA; and evaluation of the smokers' self-reported smoking status 10 months later (quitted smoking, decreased consumption; stable consumption, increased consumption).

Results

Thirty-six smokers completed the four steps. Ten months after the intervention, 11.1% of smokers quitted smoking, 52.7% decreased their consumption by 7  ±  4 cigarettes/day, 30.5% kept a stable consumption, and 5.5% increased their consumption by 9  ±  6 cigarettes/day.

Conclusion

Providing an education conference combined with announcing SLA motivated 64% of smokers to quit smoking or to reduce their cigarette consumption.

Strategies to improve smoking cessation rates in primary care

BACKGROUND

Primary care is an important setting in which to treat tobacco addiction. However, the rates at which providers address smoking cessation and the success of that support vary. Strategies can be implemented to improve and increase the delivery of smoking cessation support (e.g. through provider training), and to increase the amount and breadth of support given to people who smoke (e.g. through additional counseling or tailored printed materials).

OBJECTIVES

To assess the effectiveness of strategies intended to increase the success of smoking cessation interventions in primary care settings. To assess whether any effect that these interventions have on smoking cessation may be due to increased implementation by healthcare providers.

SEARCH METHODS

We searched the Cochrane Tobacco Addiction Group's Specialized Register, the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, and trial registries to 10 September 2020.

SELECTION CRITERIA

We included randomized controlled trials (RCTs) and cluster-RCTs (cRCTs) carried out in primary care, including non-pregnant adults. Studies investigated a strategy or strategies to improve the implementation or success of smoking cessation treatment in primary care. These strategies could include interventions designed to increase or enhance the quality of existing support, or smoking cessation interventions offered in addition to standard care (adjunctive interventions). Intervention strategies had to be tested in addition to and in comparison with standard care, or in addition to other active intervention strategies if the effect of an individual strategy could be isolated. Standard care typically incorporates physician-delivered brief behavioral support, and an offer of smoking cessation medication, but differs across studies. Studies had to measure smoking abstinence at six months' follow-up or longer.

DATA COLLECTION AND ANALYSIS

We followed standard Cochrane methods. Our primary outcome - smoking abstinence - was measured using the most rigorous intention-to-treat definition available. We also extracted outcome data for quit attempts, and the following markers of healthcare provider performance: asking about smoking status; advising on cessation; assessment of participant readiness to quit; assisting with cessation; arranging follow-up for smoking participants. Where more than one study investigated the same strategy or set of strategies, and measured the same outcome, we conducted meta-analyses using Mantel-Haenszel random-effects methods to generate pooled risk ratios (RRs) and 95% confidence intervals (CIs).

MAIN RESULTS

We included 81 RCTs and cRCTs, involving 112,159 participants. Fourteen were rated at low risk of bias, 44 at high risk, and the remainder at unclear risk. We identified moderate-certainty evidence, limited by inconsistency, that the provision of adjunctive counseling by a health professional other than the physician (RR 1.31, 95% CI 1.10 to 1.55; I2 = 44%; 22 studies, 18,150 participants), and provision of cost-free medications (RR 1.36, 95% CI 1.05 to 1.76; I2 = 63%; 10 studies,7560 participants) increased smoking quit rates in primary care. There was also moderate-certainty evidence, limited by risk of bias, that the addition of tailored print materials to standard smoking cessation treatment increased the number of people who had successfully stopped smoking at six months' follow-up or more (RR 1.29, 95% CI 1.04 to 1.59; I2 = 37%; 6 studies, 15,978 participants). There was no clear evidence that providing participants who smoked with biomedical risk feedback increased their likelihood of quitting (RR 1.07, 95% CI 0.81 to 1.41; I2 = 40%; 7 studies, 3491 participants), or that provider smoking cessation training (RR 1.10, 95% CI 0.85 to 1.41; I2 = 66%; 7 studies, 13,685 participants) or provider incentives (RR 1.14, 95% CI 0.97 to 1.34; I2 = 0%; 2 studies, 2454 participants) increased smoking abstinence rates. However, in assessing the former two strategies we judged the evidence to be of low certainty and in assessing the latter strategies it was of very low certainty. We downgraded the evidence due to imprecision, inconsistency and risk of bias across these comparisons. There was some indication that provider training increased the delivery of smoking cessation support, along with the provision of adjunctive counseling and cost-free medications. However, our secondary outcomes were not measured consistently, and in many cases analyses were subject to substantial statistical heterogeneity, imprecision, or both, making it difficult to draw conclusions. Thirty-four studies investigated multicomponent interventions to improve smoking cessation rates. There was substantial variation in the combinations of strategies tested, and the resulting individual study effect estimates, precluding meta-analyses in most cases. Meta-analyses provided some evidence that adjunctive counseling combined with either cost-free medications or provider training enhanced quit rates when compared with standard care alone. However, analyses were limited by small numbers of events, high statistical heterogeneity, and studies at high risk of bias. Analyses looking at the effects of combining provider training with flow sheets to aid physician decision-making, and with outreach facilitation, found no clear evidence that these combinations increased quit rates; however, analyses were limited by imprecision, and there was some indication that these approaches did improve some forms of provider implementation.

AUTHORS' CONCLUSIONS

There is moderate-certainty evidence that providing adjunctive counseling by an allied health professional, cost-free smoking cessation medications, and tailored printed materials as part of smoking cessation support in primary care can increase the number of people who achieve smoking cessation. There is no clear evidence that providing participants with biomedical risk feedback, or primary care providers with training or incentives to provide smoking cessation support enhance quit rates. However, we rated this evidence as of low or very low certainty, and so conclusions are likely to change as further evidence becomes available. Most of the studies in this review evaluated smoking cessation interventions that had already been extensively tested in the general population. Further studies should assess strategies designed to optimize the delivery of those interventions already known to be effective within the primary care setting. Such studies should be cluster-randomized to account for the implications of implementation in this particular setting. Due to substantial variation between studies in this review, identifying optimal characteristics of multicomponent interventions to improve the delivery of smoking cessation treatment was challenging. Future research could use component network meta-analysis to investigate this further.

Behavioural interventions for smoking cessation: an overview and network meta-analysis

BACKGROUND

Smoking is a leading cause of disease and death worldwide. In people who smoke, quitting smoking can reverse much of the damage. Many people use behavioural interventions to help them quit smoking; these interventions can vary substantially in their content and effectiveness.

OBJECTIVES

To summarise the evidence from Cochrane Reviews that assessed the effect of behavioural interventions designed to support smoking cessation attempts and to conduct a network meta-analysis to determine how modes of delivery; person delivering the intervention; and the nature, focus, and intensity of behavioural interventions for smoking cessation influence the likelihood of achieving abstinence six months after attempting to stop smoking; and whether the effects of behavioural interventions depend upon other characteristics, including population, setting, and the provision of pharmacotherapy. To summarise the availability and principal findings of economic evaluations of behavioural interventions for smoking cessation, in terms of comparative costs and cost-effectiveness, in the form of a brief economic commentary.

METHODS

This work comprises two main elements. 1. We conducted a Cochrane Overview of reviews following standard Cochrane methods. We identified Cochrane Reviews of behavioural interventions (including all non-pharmacological interventions, e.g. counselling, exercise, hypnotherapy, self-help materials) for smoking cessation by searching the Cochrane Library in July 2020. We evaluated the methodological quality of reviews using AMSTAR 2 and synthesised data from the reviews narratively. 2. We used the included reviews to identify randomised controlled trials of behavioural interventions for smoking cessation compared with other behavioural interventions or no intervention for smoking cessation. To be included, studies had to include adult smokers and measure smoking abstinence at six months or longer. Screening, data extraction, and risk of bias assessment followed standard Cochrane methods. We synthesised data using Bayesian component network meta-analysis (CNMA), examining the effects of 38 different components compared to minimal intervention. Components included behavioural and motivational elements, intervention providers, delivery modes, nature, focus, and intensity of the behavioural intervention. We used component network meta-regression (CNMR) to evaluate the influence of population characteristics, provision of pharmacotherapy, and intervention intensity on the component effects. We evaluated certainty of the evidence using GRADE domains. We assumed an additive effect for individual components.

MAIN RESULTS

We included 33 Cochrane Reviews, from which 312 randomised controlled trials, representing 250,563 participants and 845 distinct study arms, met the criteria for inclusion in our component network meta-analysis. This represented 437 different combinations of components. Of the 33 reviews, confidence in review findings was high in four reviews and moderate in nine reviews, as measured by the AMSTAR 2 critical appraisal tool. The remaining 20 reviews were low or critically low due to one or more critical weaknesses, most commonly inadequate investigation or discussion (or both) of the impact of publication bias. Of note, the critical weaknesses identified did not affect the searching, screening, or data extraction elements of the review process, which have direct bearing on our CNMA. Of the included studies, 125/312 were at low risk of bias overall, 50 were at high risk of bias, and the remainder were at unclear risk. Analyses from the contributing reviews and from our CNMA showed behavioural interventions for smoking cessation can increase quit rates, but effectiveness varies on characteristics of the support provided. There was high-certainty evidence of benefit for the provision of counselling (odds ratio (OR) 1.44, 95% credibility interval (CrI) 1.22 to 1.70, 194 studies, n = 72,273) and guaranteed financial incentives (OR 1.46, 95% CrI 1.15 to 1.85, 19 studies, n = 8877). Evidence of benefit remained when removing studies at high risk of bias. These findings were consistent with pair-wise meta-analyses from contributing reviews. There was moderate-certainty evidence of benefit for interventions delivered via text message (downgraded due to unexplained statistical heterogeneity in pair-wise comparison), and for the following components where point estimates suggested benefit but CrIs incorporated no clinically significant difference: individual tailoring; intervention content including motivational components; intervention content focused on how to quit. The remaining intervention components had low-to very low-certainty evidence, with the main issues being imprecision and risk of bias. There was no evidence to suggest an increase in harms in groups receiving behavioural support for smoking cessation. Intervention effects were not changed by adjusting for population characteristics, but data were limited. Increasing intensity of behavioural support, as measured through the number of contacts, duration of each contact, and programme length, had point estimates associated with modestly increased chances of quitting, but CrIs included no difference. The effect of behavioural support for smoking cessation appeared slightly less pronounced when people were already receiving smoking cessation pharmacotherapies.

AUTHORS' CONCLUSIONS

Behavioural support for smoking cessation can increase quit rates at six months or longer, with no evidence that support increases harms. This is the case whether or not smoking cessation pharmacotherapy is also provided, but the effect is slightly more pronounced in the absence of pharmacotherapy. Evidence of benefit is strongest for the provision of any form of counselling, and guaranteed financial incentives. Evidence suggested possible benefit but the need of further studies to evaluate: individual tailoring; delivery via text message, email, and audio recording; delivery by lay health advisor; and intervention content with motivational components and a focus on how to quit. We identified 23 economic evaluations; evidence did not consistently suggest one type of behavioural intervention for smoking cessation was more cost-effective than another. Future reviews should fully consider publication bias. Tools to investigate publication bias and to evaluate certainty in CNMA are needed.