Association of early-stage COVID-19 policy changes with smoking cessation outcomes: secondary analysis of two randomised trials in Hong Kong

Abstract

Aim To examine whether smoking cessation outcomes among Chinese-speaking adults who smoked and used community-based smoking cessation services in Hong Kong differed before and after early-stage COVID-19 policy changes. Design Secondary analysis of two randomised controlled trials, comprising one individually randomised trial and one cluster randomised trial, conducted in Hong Kong between 2018 and 2021. Setting Participants who used a community-based smoking cessation service were recruited. Participants 1762 Chinese-speaking adults who smoke or recently quit smoking (80.5% male). Measures The primary outcome was the 6-month biochemically validated abstinence rate before and after the first major policy change on 25 January 2020, when the COVID-19 emergency response level was raised. Secondary outcomes were self-reported 7-day point prevalence abstinence at 3-month and 6-month follow-ups. Sensitivity analyses were conducted for subsequent policy changes on 8 February and 28 March 2020. Modified Poisson regression models with cluster-robust SEs, adjusted for group allocation, trial, age, gender, baseline smoking intensity and intervention type, were used. Findings After the 25 January 2020 policy cut-off, the 6-month biochemically validated abstinence rate significantly decreased from 12.3% before the cut-off to 6.8% (risk ratio (RR) (95% CI) 0.55 (0.40 to 0.76), p<0.001) after the cut-off. Self-reported 7-day abstinence rates were also lower after the policy change at the 3-month (49.1% vs 31.3%, 0.60 (0.51 to 0.71), p<0.001) and 6-month (41.0% vs 32.2%, 0.78 (0.69 to 0.88), p<0.001) follow-ups. Sensitivity analyses using the 8 February and 28 March cut-off points showed generally consistent reductions in abstinence outcomes. Conclusion Early-stage COVID-19 policy changes in Hong Kong were associated with significantly lower tobacco abstinence rates among adults using or being referred to community-based smoking cessation services. Rapidly adaptable cessation support, including telehealth counselling and continuity of pharmacotherapy, is needed to sustain quit attempts during public health emergencies.