Background: Blended face-to-face and web-based treatment is a promising mode to deliver smoking cessation treatment. In an outpatient clinic in a Dutch Hospital effectiveness of a blended treatment (BSCT) was compared to usual face-to-face treatment (F2F). The results from 6 months post-treatment follow-up are presented here.

Methods: In this open-label two-arm non-inferiority RCT patients (N=344) of a Dutch outpatient smoking cessation clinic were assigned either to the blended smoking cessation treatment (BSCT, N=167) or a face-to-face treatment with identical ingredients and duration (F2F, N=177). CO-validated point prevalence abstinence at 6 months follow-up, taken shortly after end of treatment was analyzed. Intention-to-treat analyses were performed, retaining missing participants as continuing smokers. Non-inferiority was assessed based on a one-sided margin of five percentage points difference between arms. Additionally, a Bayes Factor was estimated (with a BF>3 supporting non-inferiority, and a <.3 rejecting non-inferiority).

Method: At 6 months follow up, 23 BSCT participants (13.8%) and 31 F2F participants (17.5%) were abstinent, with a difference of 3.7% (95%CI: 11.4;-4.0) in favor of F2F. Furthermore, a BF=1.28 was found.

Discussion: Based on observed biochemically validated abstinence rates, this RCT suggests that delivering outpatient smoking cessation treatment in a blended mode yields comparable quit rates as full face-to-face treatment mode. However, non-inferiority could not be supported conclusively. Ignoring patient preferences for either of the delivery modes may explain these inconclusive findings.