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

objectivesThe 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.

designObservational study.

settingData are drawn from 221 physician-led primary care practices participating in a smoking cessation program in Ontario, Canada.

participants43 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.

interventionNicotine-replacement therapy with counselling. PRIMARY OUTCOME MEASURE: 7-day self-reported abstinence from cigarettes at a follow-up survey 6 months after entry.

resultsFor 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.

conclusionThe 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.