Comparing different intensities of active referral to smoking cessation services in promoting smoking cessation among community smokers: a study protocol of a cluster randomized controlled trial.

Background: Actively referring smokers to smoking cessation (SC) services could increase quitting and is scalable for the population. The objective of this study is to compare 2 different intensities of SC active referral for smokers in the community of Hong Kong.

Methods/design: This is a single-blind, parallel 3-armed cluster randomized controlled trial (cRCT) consisting of high-intensity SC active referral (HAR Group), low-intensity SC referral by text messaging on promoting SC services use (Text Group) and a control group receives general very brief advice. Biochemically validated daily smokers will be proactively recruited in the community from 68 clusters (recruitment sessions). The primary outcome is self-reported 7-days point prevalence abstinence (PPA) at the 3- and 6- month follow-ups. Secondary outcomes are SC service use, smoking reduction rate (SRR, daily cigarette consumption reduced by ≥50%; excluding quitters) and biochemically validated quit rate (exhaled CO < 4 ppm and salivary cotinine < 10 ng/ml). Outcome assessors and data analysts will be blinded to group allocation. Intention-to-treat principle and Generalized Estimating Equation (GEE) regressions will be used for data analysis.

Discussion: This will be the first trial on evaluating the efficacy of the 2 different intensities of SC active referral on smoking cessation in community smokers. It is anticipated that the results from this trial can provide evidence to the effectiveness of high-intensity active referral to SC services and low intensity SC referral by using text messaging in achieving smoking abstinence.

Trial Registration: ClinicalTrials.gov Identifier: NCT02804880 , June 17, 2016.