Rates of retention of persons with a mental health disorder in outpatient smoking cessation and reduction trials, and associated factors: protocol for a systematic review and meta-analysis

Abstract

IntroductionSmoking among persons with a mental health disorder is associated with inequitable health, social and economic burden. Randomised controlled trials (RCTs) are considered the gold standard design for the assessment of healthcare intervention efficacy/effectiveness. However, many RCTs of smoking interventions for persons with a mental health disorder lack rigour due to low participant retention. No systematic review has pooled retention rates in randomised trials of smoking interventions for persons with a mental health disorder or explored associated factors. The aims of the systematic review will therefore be to: (1) summarise overall rates of participant retention in smoking cessation and reduction trials involving persons with a mental health disorder (including for experimental and control groups separately) and (2) determine if retention rates vary according to participant, environmental, researcher and study factors.Methods and analysisPsycINFO, EMBASE, MEDLINE, CENTRAL and The Cochrane Tobacco Addiction Review Group Specialised Register will be searched for reports of RCTs of outpatient smoking cessation or reduction interventions for adults with a mental health disorder. The search terms will include MeSH terms and free text words, and there will be no language or date restrictions. All databases will be searched from inception to present. Data will be analysed using the Mantel-Haenszel fixed-effect model, and where substantial heterogeneity (I2>50%) is detected, DerSimonian & Laird inverse-variance random effects model. Pooled estimates and 95% CIs will be calculated for overall participant retention rates and for intervention and control trial arms separately. Associations between participant retention and participant, environmental, researcher and study factors will be assessed via subgroup analyses and, where sufficient data are obtained, meta-regression.Ethics and disseminationThis study does not require ethical approval. The findings of this review will be disseminated via publication in a peer-reviewed open access medical journal and presentations at international scientific meetings.

Opportunities and challenges of delivering digital clinical trials: lessons learned from a randomised controlled trial of an online behavioural intervention for children and young people

“…Although it is not possible to make a direct comparison on trial design/population with the STEPS paper, it is interesting that over 10 years later, recruitment still remains a significant barrier in successful trial completion. Similarly, in line with previous studies, we also found evidence of poor retention rates in trials of psychological interventions [ 15 ]. Only 47% of the studies achieved their specified follow-up rate even with extensions, indicating that the majority of trials were potentially under-powered.…”

“…Whilst average retention in trials has been estimated at 89% [13], which may suggest that retention is less of a concern than recruitment, this figure is likely inflated by trials with only short-term follow-ups. Retention has also been shown to be particularly challenging in certain clinical groups or types of intervention, such as behavioural intervention trials involving participants with a mental health disorder [15]. Studies on smoking cessation for participants with depression or substance use disorders, for example, have reported follow-up rates as low as 27-33% [16,17].…”

“…Though underlying factors behind poor retention are difficult to measure, participants report fatigue at completing lengthy assessments, or outcome measures that do not seem relevant to their condition or lived experience [ 18 ]. Poor retention has substantial implications to a trial, including, increasing study costs by requiring a larger sample size to achieve adequate power, and creating bias in results caused by attrition [ 19 ], particularly if there is a differential drop-out rate between group allocation which cannot fully be accounted for using statistical methods (such as multiple imputation) [ 15 ]. As such, researchers have also examined factors that influence good retention and found good communication which is adapted to suit the individual participant as well as regular reminders from trial staff to be beneficial [ 20 ].…”

Comparing the Effectiveness of the Blended Delivery Mode With the Face-to-Face Delivery Mode of Smoking Cessation Treatment: Noninferiority Randomized Controlled Trial

“…We identified 2 main predictors of dropout: having a smoking partner at baseline and lower mental health scores as indicated by the Depression Anxiety Stress Scale [ 50 ]. Both predictors are known to be associated with poorer treatment outcomes [ 51 ]. This finding suggests that neither of the interventions used in this study sufficiently reduced the barriers to successful intervention completion.…”