Smartphone Application for Smoking Cessation (Quit with US): A Randomized Controlled Trial among Young Adult Light Smokers in Thailand

This study aimed to determine the efficacy of a smartphone application named Quit with US among young adult smokers. An open-label, parallel, 2-group, randomized controlled trial with a 12-week follow-up was conducted between March and November 2020 among undergraduate students (18 to 24 years) in Chiang Mai Province, Thailand. A total of 273 participants were assigned by simple randomization procedure to the Quit with US intervention group (n = 137) or the control group (n = 136). All participants received pharmacists' smoking cessation counseling at baseline and follow-ups. In addition, the intervention group's participants were advised to use Quit with US. The baseline and 12-week follow-up assessments were conducted at a study unit, whereas other follow-ups were completed over the telephone. The primary abstinence outcome was the exhaled CO concentration level (<= 6 ppm) verified 7-day point prevalence abstinence. At baseline, the participants' mean (standard deviation) age was 21.06 (1.62) years. Most identified as daily smokers (57.9%, n = 158), consumed <= 10 cigarettes daily (89.4%, n = 244), and expressed low level of nicotine dependence as measured by Heaviness of Smoking Index score (86.1%, n = 235). Regarding intention-to-treat analyses, participants in the Quit with US intervention group achieved significantly greater smoking abstinence rate than those in the control group (58.4% (80/137) vs. 30.9% (42/136), risk ratio = 1.89, 95% confidence intervals = 1.42 to 2.52, p < 0.001). In conclusion, Quit with US integrated with pharmacists' smoking cessation counseling significantly enhanced smoking abstinence rates among young adult light smokers consuming <= 10 cigarettes daily.