CRD summary

This review concluded that behavioural smoking cessation interventions appeared promising for some disadvantaged groups but overall findings were inconsistent. The authors' conclusions reflect the evidence presented, but the generally low quality of the evidence suggests that the conclusions should be interpreted cautiously.

Authors' objectives

To assess the effectiveness of behavioural smoking cessation interventions targeted at members of specific disadvantaged groups.

Searching

The Cochrane Library, EMBASE and PsycINFO were searched to October 2010. Search terms were reported. Tables of contents of relevant journals (Tobacco Control, Nicotine and Tobacco Research and the Journal of public Health) were searched manually from for 2005 to 2010. Previous review articles, the grey literature databases Greynet and OpenSIGLE, and reference lists of retrieved articles were searched for relevant studies. Researchers in the field were contacted to identify further eligible studies. It was unclear whether there were language restrictions on the search, but only English-language studies were included in the review.

Study selection

Randomised controlled trials (RCTs) and controlled clinical trials (CCTs) of behavioural smoking cessation interventions aimed at disadvantaged groups were eligible for the review. Participants had to be homeless, prisoners, members of indigenous populations, at-risk youth, on a low income, or people with a mental illness. Eligible trials had to be conducted in a developed country and report smoking cessation as an outcome. Eligible comparators were another behavioural intervention or usual care. Trials where pharmacotherapy was part of the intervention were only included when the pharmacotherapy was not being tested for effectiveness. Population-based interventions were excluded. The primary outcome was smoking abstinence six months or more after starting the intervention.

Most included trials evaluated behavioural support interventions (interventions based on motivational interviewing principles or behavioural counselling). Most trials were conducted in the USA in primary or community care settings; one trial was conducted in the UK. Some trials included nicotine replacement therapy as part of the intervention. Carbon monoxide levels, cotinine in saliva or urine, or both were used to confirm smoking status in most trials. Loss to follow-up at the longest follow-up point ranged from 8 to 77% (where reported).

One reviewer screened titles and abstracts retrieved by the searches and rejected studies that clearly did not meet inclusion criteria. Remaining studies were assessed for inclusion by two reviewers; the authors did not state how disagreements were resolved.

Assessment of study quality

Methodological quality was assessed using the Effective Public Health Practice Project quality assessment tool, which covered selection bias; study design; control of confounders; blinding; data collection methods; and withdrawals and drop-outs. Overall quality was rated as 'strong', 'moderate' or 'weak'.

Quality was assessed by two reviewers independently; any disagreements were resolved by discussion.

Data extraction

Data on numbers of participants and outcomes in each group were extracted to calculate risk ratios (RRs) and associated 95% confidence intervals (CIs) at short-term (three months or less) and long-term (six months or more) follow-up.

The authors did not state how many reviewers performed the data extraction.

Methods of synthesis

Trials that involved a particular disadvantaged group were pooled by meta-analysis using a DerSimonian and Laird random-effects model. Short-term and long-term follow-up were assessed separately. Heterogeneity was assessed using I². Subgroup analyses were performed for some disadvantaged groups.

A narrative synthesis by population targeted was also provided.

Results of the review

Thirty-two studies (13 RCTs, 16 CCTs and three cluster RCTs) with 13,605 participants were included. Of the included trials, one involved homeless people, two involved indigenous populations, one involved prisoners, six involved at-risk youth, 12 involved low-income populations and ten involved people with a mental illness. Two trials were rated methodologically strong, 10 trials as moderate and 20 trials as weak. Follow-up ranged from four to six weeks to four years

Statistically significant beneficial effects of behavioural interventions were seen for low income women at short-term follow-up (RR 1.68, 95% CI 1.21 to 2.33; three trials) and for people with mental illness at long-term follow-up (RR 1.35, 95% CI 1.01 to 1.81; seven trials). Heterogeneity was low in these analyses (I²=0%).

Other meta-analyses showed statistically non-significant differences between behavioural intervention and control groups.

Authors' conclusions

Use of behavioural smoking cessation interventions appeared promising for some disadvantaged groups but overall findings were inconsistent

CRD commentary

The review question and inclusion criteria were clear. Inclusion of non-randomised trials meant that the review was not limited to the best study design for answering the review question. The authors searched a range of relevant sources and attempted to identify grey literature and unpublished trials. However, risk of publication bias was not formally assessed. The review was limited to English-language trials, so relevant trials reported in other languages could have been omitted. The use of independent assessment by two reviewers to minimise errors and bias varied between different stages of the review process.

Trial quality was assessed using appropriate criteria and relevant details of included studies were reported. Trials that involved similar populations and interventions were pooled by meta-analysis. Statistical heterogeneity was assessed and was low in most analyses. As noted by the authors, most meta-analyses involved small numbers of trials and participants, which limited their ability to detect any differences between groups. Some of the meta-analyses involved subgroups not mentioned in the methods; the reliability of such ad hoc analyses was uncertain. Only one included trial was conducted in the UK, so generalisability of the findings to UK settings was uncertain.

The authors' conclusions reflect the evidence presented, but the generally low quality of the evidence suggests that the conclusions should be interpreted cautiously.

Implications of the review for practice and research

Practice: The authors did not state any implications for practice.

Research: The authors stated that future RCTs should involve larger samples, giving more statistical power to detect clinically meaningful effects. They also suggested that research should focus on interventions that have received little attention to date (such as financial incentives) and on interventions delivered outside standard healthcare settings.

Funding

Not stated.

Bibliographic details

Bryant J, Bonevski B, Paul C, McElduff P, Attia J. A systematic review and meta-analysis of the effectiveness of behavioural smoking cessation interventions in selected disadvantaged groups. Addiction 2011; 106(9): 1568-1585. [PubMed: 21489007]

Original Paper URL

http://onlinelibrary.wiley.com/doi/10.1111/j.1360-0443.2011.03467.x/abstract

Indexing Status

Subject indexing assigned by NLM

MeSH

Behavior Therapy /methods; Controlled Clinical Trials as Topic; Databases, Bibliographic; Great Britain; Health Status Disparities; Homeless Persons; Humans; Mentally Ill Persons; New Zealand; Outcome Assessment (Health Care) /statistics & numerical data; Population Groups; Poverty; Prisoners; Randomized Controlled Trials as Topic; Self Care; Smoking /epidemiology /prevention & control; Smoking Cessation /methods /statistics & numerical data; United States; Vulnerable Populations

AccessionNumber

12011006035

Database entry date

14/12/2011

Record Status

This is a critical abstract of a systematic review that meets the criteria for inclusion on DARE. Each critical abstract contains a brief summary of the review methods, results and conclusions followed by a detailed critical assessment on the reliability of the review and the conclusions drawn.