Smoking cessation in severe mental illness: combined long-term quit rates from the UK SCIMITAR trials programme.

Smoking contributes to health inequalities for people with severe mental illness (SMI). Although smoking cessation interventions are effective in the short term, there are few long-term trial-based estimates of abstinence. The SCIMITAR trials programme includes the largest trial to date of a smoking cessation intervention for people with SMI, but this was underpowered to detect anticipated long-term quit rates. By pooling pilot and full-trial data we found that quit rates were maintained at 12 months (OR = 1.67, 95% CI 1.02-2.73, P = 0.04). Policymakers can now be confident that bespoke smoking cessation interventions produce successful short- and long-term quitting.