BackgroundThe demand for smoking cessation services has risen in Turkey, as smokers planning to quit reached 35% in 2012. Communication technologies are used globally to support quitters, yet their integration to health services is rare. This study aims to evaluate the effect of support messages through WhatsApp application added to the usual care of a university hospital cessation unit, as compared to usual care alone, on abstinence rates at first month.MethodsA randomized controlled intervention study was conducted with 132 patients applying to Ege University Hospital's Department of Public Health Smoking Cessation Clinic, between March and July 2017. Intervention content was prepared and 60 WhatsApp messages about having a plan of action and preventing relapse were developed through expert panels. These messages lasted for 3months and follow-ups continued for 6months. The primary outcome was abstinence rate at 1st month post target quit day. As secondary outcomes; the continuous abstinence rates at 3rd and 6th months, number of follow-ups, change in weight and continuity of medication were evaluated. Intention-to-treat analysis was used.ResultsAbstinence rate at 1st month was 65.9% in the intervention group and 40.9% in the control group (p=0.007); 50.0 and 30.7% at 3rd month and 40.9 and 22.7% at 6th month, consecutively (both p<0.05). Being in the intervention group increased abstinence rate by 3.50 (OR, 95% CI=1.30-9.44) times in the 1st month. When controlled for all other factors in the multivariate logistic regression, the intervention was the only variable significantly associated with abstinence. For secondary outcomes, the intervention increased abstinence rate by 2.50 (OR, 95% CI=1.08-6.40) times in the 3rd and 2.31 (OR, 95% CI=1.03-5.16) times in the 6th month. In the intervention group, the number of follow-ups and face-to-face follow-ups were higher at 1st and 3rd months and continuity of medication was longer at 3rd month.ConclusionsWhatsApp support embedded in cessation service delivery increases the abstinence rate and has favorable effects on follow-up.Trial registrationThis trial is retrospectively registered online at ClinicalTrials.gov with the identifier NCT03714971.