Randomised controlled trial of the effects of differently tailored smoking cessation interventions among failed quitters of the NHS Stop Smoking Services: an application of the TTM.

Background Stop Smoking Services (SSS) were created to help people quit smoking and the original training guidelines place the Services’ intervention within the framework of the Transtheoretical Model (TTM). However, more than half of all smokers using the SSS fail to quit. Therefore, the aim of this study was to investigate the effectiveness of a computer-tailored intervention based on the TTM among failed quitters of the SSS. Method Unsuccessful quitters (N=517) were recruited from the databases of five SSS in the Avon area and completed questionnaires measuring demographic characteristics, smoking-related behaviour and TTM variables. Questionnaires were delivered and returned via post. Participants were randomised into one of three groups. The control group received a letter of thanks for participating in the study. Participants in the staged-based intervention received the same letter as controls plus feedback based only on their stage of change and those in the fully tailored intervention received the same letter as controls plus feedback tailored to all components of the TTM. Findings At baseline participants averaged 43.7 years old and approximately 63% and 22% were in the contemplation and preparation stages of change. Based on an intention-to-treat analysis, there were no significant differences between the groups for smoking cessation at the 9 month follow-up; 6.8% in the control, 5.3% in the stage-based and 6.7% in the tailored groups were abstinent. Also, only one TTM variable measured at baseline significantly predicted smoking status at the 9 month follow-up: stage of change. None of the other TTM variables were predictive of smoking status. Conclusions The TTM interventions were of no benefit to the smokers in this study and the staged-based intervention had a negative overall impact on participants. Therefore the TTM is unlikely to make a significant improvement on the services currently provided for failed quitters of the SSS