Introduction:
Text messaging (SMS) smoking cessation programs can reach a large amount of cigarette smokers and are effective in increasing quit rates, but their efficacy has not yet been explored in Vietnam.

Objectives:
To develop and test the feasibility, acceptability, and preliminary effect of a bidirectional SMS cessation intervention among smokers in Vietnam.

Methods:
A two-arm pilot randomized controlled trial was conducted in Ha Noi to compare a 6-week bidirectional SMS cessation program (intervention) and weekly text assessments of smoking status (control) among 98 adult male cigarette/waterpipe smokers. Baseline, 6 weeks, and 3 months surveys were conducted. Outcomes were feasibility, acceptability, biochemically verified 7-day point prevalence abstinence, and smoking behavior.

Results:
100% enrolled participants retained over the intervention. Participants’ assessment of the SMS program was positive: 90% reported that the program was “very helpful” or “somewhat helpful”; 98% were “very satisfied” or “satisfied” with the program; 96% reported the program was easy to use and learned a lot from the program; 94% reported that the text messages motivated and helped them to quit. Biochemically verified abstinence was statistically higher in intervention group than the control group at 6 weeks (20.8% vs. 2.0%; p<0.01), but decreased and not significantly different at 3 months (12.5% vs. 5.9%; p>0.05). Mean number of cigarettes smoked per day reduced significantly: 15.4 cigarette and 14.3 times of waterpipe use among intervention group at baseline decreased to 5.8 cigarettes and 5.3 times of waterpipe use at 3 months.

Consclusions:
The SMS smoking cessation program was feasible, acceptable and showed positive preliminary effectiveness to increase quit rates among Vietnamese smokers. A large scale expansion of the SMS cessation program is needed to provide support for smoking cessation in Vietnam.