Efficacy of brief motivational interviewing delivered via mobile instant messaging tools in promoting smoking cessation among unmotivated smokers with chronic diseases : a randomised controlled trial

Abstract

Smoking plays a causal role in the development of chronic diseases and may increase the risk of disease progression or recurrence, elevate the risk of mortality, and reduce the efficacy of treatment for disease sufferers. Nevertheless, a majority of smokers with chronic diseases are unmotivated, having no intention to quit. The aims of this thesis were to (1) summarise the literature on the design and efficacy of smoking cessation interventions targeting smokers with chronic diseases and (2) examine the efficacy of brief motivational interviewing (MI) delivered by means of mobile instant messaging tools in encouraging these smokers to quit. Thus, a systematic review conducted according to the Cochrane Handbook for Systematic Reviews of Interventions informed the design and conduct of a pilot randomised controlled trial (RCT) examining the feasibility and acceptability of the brief MI intervention. The results of the pilot study, in turn, informed the implementation of the main RCT of 467 unmotivated smokers with chronic diseases over the age of 17 recruited at two Special Out-Patient Clinics in Hong Kong. Of these participants, 233 were assigned randomly to the intervention group (a brief MI intervention) and the other 234 to the control group (a placebo intervention). The primary outcome was the biochemically validated 7-day point-prevalence abstinence (PPA) at 6 months. The secondary outcomes included the biochemically validated 7-day PPA at 12 months and the self-reported 7-day PPA, intention to quit, self-reported smoking reduction of at least 50%, quit attempts, and self-reported behavioural change at 3, 6, and 12 months. The data analysis followed the intention-to-treat principle. The systematic review indicated that an intensive intervention delivered by healthcare professionals was more effective in promoting smoking cessation among chronic disease patients than minimal counselling. However, the review also identified methodological flaws in most previous studies. The main RCT showed that the point estimates of biochemically validated 7-day PPA at 6 months, intention to quit at 3 and 6 months, self-reported smoking reduction of at least 50% at 6 months, quit attempts at 6 months, and self-reported behavioural change at 3 and 6 months were all statistically significantly higher in the intervention group than those in the control group. Around half of the participants demonstrated effective engagement with the intervention, which was significantly associated with the biochemically validated quit rate at 6 months. This thesis will be of interest to healthcare professionals involved in the design and implementation of smoking cessation interventions that target unmotivated smokers with chronic diseases, a population that needs to be reached in order to continue curbing the tobacco epidemic. The RCT shed light on the efficacy of brief MI delivered by means of mobile instant messaging tools in promoting smoking cessation, showing that the intervention is suited to clinical settings. Effective smoking cessation interventions are needed for this subset of smokers, both to improve their health and to reduce the burdens that chronic diseases place on healthcare systems. Future studies are called for to evaluate the intervention further and understand better smokers’ perceptions of it.