Primary and secondary outcomes
REGRESSION, SECONDARY
For the primary and secondary outcome measures, differences between the two groups at the follow-up intervals with respect to prolonged abstinence and 4-week and 7-day point prevalence of abstinence were analysed using logistic regression. Negative binomial regression was used to analyse the number of quit attempts, use of other smoking cessation services, and cigarettes smoked weekly (amongst those who still smoked). Models were adjusted for baseline characteristics (gender, age, nicotine dependence, importance, confidence, and know-how) as well as the stratifying variable in the randomisation procedure (general or surgery eligibility).Effect modification analyses were performed for the primary outcomes, exploring interactions between group allocation and baseline variables. We also estimated effect modification based on which setting participants were recruited from (online or primary health care) and which version of the intervention they were eligible for (general or surgery).