Testing Proof-Of-Concept Outcomes of a Smoking Cessation Smartphone App for Nondaily Smokers: Protocol for a Proof-Of-Concept Randomized Controlled Trial (Preprint)

Abstract

Nondaily smoking is a wide-spread, increasingly prevalent pattern of smoking that is particularly prevalent in ethnic minority and vulnerable populations such as persons with mental health and substance use challenges. To date, no effective treatment approach for this type of smokers has been identified.

To use a randomized controlled trial to evaluate proof-of-concept markers of the Smiling instead of Smoking (SiS) app, a smoking cessation smartphone app designed specifically for nondaily smokers. This app was iteratively developed and is now in its 3rd Version. Prior studies have demonstrated acceptability and feasibility when participants were onboarded in person (Study 1) and remotely (Study 2), and showed within-person changes in line with hypothesized mechanisms of change. This is the first randomized test of this app.

A total of 225 adult nondaily smokers will be asked to undertake a quit attempt while using their smoking cessation support materials for a period of seven weeks, one week prior to and six weeks following their chosen quit date. Participants will be randomized to use one of the three following materials: the SiS smartphone app vs. the National Cancer Institute (NCI)’s smartphone app QuitGuide (QG) vs. the NCI’s smoking cessation brochure “Clearing the Air” (CtA). All participants will participate in a 15-minute scripted onboarding phone-call, during which study staff will introduce participants to their support materials. Survey links will be sent for 2, 6, 12, and 24-week follow-ups, anchored on the participants’ initially chosen quit date. The primary outcome is self-efficacy to remain abstinent from smoking at treatment end, as measured by the Smoking Self-Efficacy Questionnaire. Secondary outcomes cover several domains relevant to treatment development and implementation: treatment acceptability (e.g., satisfaction with smoking cessation support, as measured by the Client Satisfaction Scale; app usability, as measured by the System Usability Scale), treatment feasibility (e.g., as measured by the number of days participants used the SiS/QG app during the prescribed treatment period, the extent to which they used smoking cessation strategies), and, in an exploratory way, treatment efficacy as assessed by self-reported 30-day point prevalence abstinence.

Recruitment began in January 2021 and will continue until July 2022. The final 24-week follow-up is expected to be completed in January 2023. The trial is funded by the American Cancer Society.

This study is designed to test if the SiS app warrants testing in a large-scale randomized controlled trial to test its effectiveness in supporting smoking cessation for nondaily smokers. The design of this study also enables insights into issues pertinent to smoking cessation smartphone app treatment development and implementation by measuring, in a randomized design, markers of treatment satisfaction, engagement with the technology and content of the treatment, and adherence to the treatment plan.

NCT04672239