Variability and effectiveness of comparator group interventions in smoking cessation trials: a systematic review and meta-analysis.

Nicola Black,Susan Michie,Wolfgang Viechtbauer,Marie Johnston,Jamie Hartmann‐Boyce,Maarten C Eisma,Robert West,Marijn De Bruin

doi:10.1111/add.14969

Abstract

AimsTo examine variability and effectiveness of interventions provided to comparator (control) groups in smoking cessation trials.MethodsSystematic review with meta‐analysis of randomized controlled trials (RCTs) of behavioral interventions for smoking cessation, with or without stop‐smoking medication. We searched the Cochrane Tobacco Addiction Group Specialized Register for RCTs with objective outcomes measured at ≥ 6 months. Study authors were contacted to obtain comprehensive descriptions of their comparator interventions. Meta‐regression analyses examined the relationships of smoking cessation rates with stop‐smoking medication and behavior change techniques.ResultsOne hundred and four of 142 eligible comparator groups (n = 23 706) had complete data and were included in analyses. There was considerable variability in the number of behavior change techniques delivered [mean = 15.97, standard deviation (SD) = 13.54, range = 0–45] and the provision of smoking cessation medication (43% of groups received medication) throughout and within categories of comparator groups (e.g. usual care, brief advice). Higher smoking cessation rates were predicted by provision of medication [B = 0.334, 95% confidence interval (CI) = 0.030–0.638, P = 0.031] and number of behavior change techniques included (B = 0.020, 95% CI = 0.008–0.032, P < 0.001). Modelled cessation rates in comparator groups that received the most intensive support were 15 percentage points higher than those that received the least (23 versus 8%).ConclusionsInterventions delivered to comparator groups in smoking cessation randomized controlled trials vary considerably in content, and cessation rates are strongly predicted by stop‐smoking medication and number of behavior change techniques delivered.

Highlights

Tobacco smoking is a leading cause of premature mortality, disease and health-care expenditures [1,2]
The observed effect sizes will be a function of the effectiveness of the intervention provided to the experimental group, and the intervention provided to the corresponding control group, or ‘comparator
The comparator groups included in the present analyses were the single least intensive groups in each randomized controlled trials (RCTs), which could have included no support, medication, usual care or comparator interventions introduced by the researchers

Summary

Introduction

Tobacco smoking is a leading cause of premature mortality, disease and health-care expenditures [1,2]. The evidence generated has informed smoking cessation guidelines and health-care services and helped numerous people to quit smoking [12,13]. Accurate evidence can optimize the effectiveness of these interventions and ensure that services offered are those which are most cost-effective. The effectiveness of smoking cessation interventions is commonly determined by comparing them with an active control. The observed effect sizes will be a function of the effectiveness of the intervention provided to the experimental group, and the intervention provided to the corresponding control group, or ‘comparator

Methods

Results

Conclusion