Effect of COVID-19 on smoking cessation outcomes in a large primary care treatment programme: an observational study

OBJECTIVES: The COVID-19 pandemic has changed patterns of smoking, other substance use and other health-related behaviours, leading to a virtualisation of non-urgent medical care. In this study, we examine associated changes in outcomes of smoking-cessation treatment. DESIGN: Observational study. SETTING: Data are drawn from 221 physician-led primary care practices participating in a smoking cessation program in Ontario, Canada. PARTICIPANTS: 43 509 patients (53% female), comprising 35 385 historical controls, 6109 people enrolled before the pandemic and followed up during it, and 1815 people enrolled after the pandemic began. INTERVENTION: Nicotine-replacement therapy with counselling. PRIMARY OUTCOME MEASURE: 7-day self-reported abstinence from cigarettes at a follow-up survey 6 months after entry. RESULTS: For people followed up in the 6 months (6M) after the pandemic began, quit probability declined with date of enrolment. Predicted probabilities were 31.2% (95% CI 30.0% to 32.5%) for people enrolled in smoking cessation treatment 6 months prior to the emergency declaration and followed up immediately after the state of emergency was declared, and 24.1% (95% CI 22.1% to 26.2%) for those enrolled in treatment immediately before the emergency declaration and followed up 6M later (difference=−6.5%, 95% CI −9.0% to −3.9%). Seasonality and total treatment use did not explain this decline. CONCLUSION: The probability of successful smoking cessation following treatment fell during the pandemic, with the decline consistent with an effect of ‘exposure’ to the pandemic-era environment. As many changes happened simultaneously, specific causes cannot be identified; however, the possibility that virtual care has been less effective than in-person treatment should be explored.