Aims: To assess the impact of English treatment services on CO-validated quit rates at 52-week follow-up, to explore the relationship between service-related characteristics and socio-demographic and behavioural factors with cessation outcomes, and to compare the characteristics of service users lost to follow-up with CO-validated quitters.
Design: Observational study of administrative information linked with survey data for 2069 recipients of smoking treatment services who set a quit date between May and November 2002.
Setting: Two contrasting areas of England, Nottingham and North Cumbria, consisting of nine primary care trust (PCT) localities.
Measurements: Routine monitoring data specified by the Department of Health included information about basic demographic characteristics, postcode of residence from which a deprivation category was identified, nature of intervention, and smoking status at 4-week follow-up. These data were supplemented with information about smoking status at 52 weeks, referral pathways, relapse experiences, number of follow-up contact attempts, socio-economic status and smoking-related behaviours obtained from consenting service recipients by treatment advisers.
Findings: One user in seven (14.6%) reported prolonged abstinence and was CO-validated as a successful quitter at 52 weeks. This rose to 17.7% when self-report cases were included. Relapse rates between 4 and 52 weeks were almost identical between the two study areas--75%. Relapse was most likely to occur in the first 6 months following treatment. Users who self-reported quitting at 4 weeks were less likely (13.7%) than those with biochemical verification of smoking status at 4 weeks (25.2%) to be CO-validated quitters at 52 weeks (P = 0.004). Older users (OR 1.023; CI 1.014-1.032), people who smoke mainly for pleasure rather than to cope (OR 1.38; CI 1.02-1.87), and those who were extremely determined (OR 1.58; CI 1.21-2.05) were more likely to be quitters at 52-week follow-up, whereas those with lower socio-economic status (OR 0.86; CI 0.78-0.96), who smoked their first cigarette of the day within 5 minutes of waking (OR 0.73; CI 0.55-0.96) or had another smoker in their household (OR 0.65; CI 0.49-0.86) were less likely. In contrast, users lost to follow-up tended to be younger and experienced different referral pathways than CO-validated quitters. Gender was not statistically significantly associated with cessation at 52 weeks and nor were any of the key characteristics of intervention, such as group or one-to-one counselling.
Conclusions: These results obtained from routine services are consistent with those obtained from clinical trials in relation to abstinence at one year. Given that a high proportion of smokers relapsed between 4 weeks and 1 year it is important that future assessments of longer-term outcomes are conducted. However, following-up service users many months after an intervention is expensive, and reasonable estimates of quit rates can be estimated from short-term outcomes, provided that they have been CO-validated. Future studies should monitor outcomes from a selection of services treating different groups of smokers, particularly if more is to be learned about the role of smoking treatment services in reducing inequalities in health.