Effectiveness of mobile smoking cessation treatment with 1-week nicotine replacement therapy sampling at outdoor smoking hotspots: A cluster randomized controlled trial.

Aims: To evaluate the effectiveness of mobile smoking cessation (SC) treatment with 1-week nicotine replacement therapy (NRT) sampling on recruitment and quitting outcomes.

Design: Two-arm cluster RCT (1:1 ratio), single-blinded, at 244 recruitment sessions in Hong Kong outdoor smoking hotspots from October 2018-December 2019.

Setting: Participant were recruited by ambassadors and treated at the mobile SC truck.

Participants: 834 adult (≥18 years, male 81.3%) daily smokers, Chinese-speaking, non-NRT users in the past month, consented after nurse-led intervention in mobile SC truck were randomized to the experimental (n = 482 male 79.5%) and the control group (n = 352, male 83.8%).

Intervention And Comparator: The experimental group received a 1-week free NRT sample, an NRT instruction card, and mobile SC treatment including onsite nurse-led brief medication advice (about 15 minutes) and referral to SC clinics. The control group received the same mobile SC treatment.

Measurements: Primary outcome was self-reported quit attempts at 1-month follow-up. Secondary outcomes included SC service use at 1 month, and biochemically validated abstinence (exhaled carbon monoxide < 4 ppm; or saliva cotinine < 10 ng/ml) at 6-month follow-up. Additionally, a post-hoc cost analysis was conducted.

Findings: By intention-to-treat, the two groups showed similar prevalence of quit attempts (44·4% versus 43·5%, risk ratio (RR) = 1·04, 95% confidence interval (CI) = 0·79-1·37, P = 0·79). Compared with the control group, the experimental group showed lower SC service use at clinics (32·4% versus 44·9%, RR = 0·72, 95%CI = 0·57-0·91, P = 0·006), but no significant difference in validated abstinence (4·6% versus 2·8%, RR = 1·64, 95%CI = 0·76-3·50, P = 0·21). The experimental recruitment sessions recruited more smokers for onsite medication advice than the control session (mean 6·7 vs 5·0, adjusted incident rate ratio = 1·30, 95%CI = 1·08-1·56, P = 0·005).

Conclusions: Mobile smoking cessation treatment with 1-week nicotine replacement therapy sampling did not increase quit attempts or abstinence outcomes among recruited daily smokers in Hong Kong. The intervention increased smokers' uptake of onsite medication advice but reduced subsequent smoking cessation service use at clinics.