Spirometry and smoking cessation advice in general practice: a randomised clinical trial

RATIONALE: To assess the success rate of smoking cessation with the "minimal intervention strategy" in general practice, and to determine the influence of spirometry on this success rate. METHODS: Training in smoking cessation advice was given to 16 general practitioners (GPs). During 12 weeks, these GPs screened their practice population for smoking habits, the degree of dependence on nicotine, and the motivation to quit smoking. Patients willing to stop were randomised to a group that underwent a single office spirometry, or to a control group. The GPs were asked to support the attempts with the minimal intervention strategy. Success rates were compared after 6, 12 and 24 months. RESULTS: On a population of 5590 patients, 1206 smokers were identified (22%). To the vulnerable group, identified following the Prochaska and Di Clemente scheme, the proposal was made to change smoking behaviour. Two hundred and twenty-one patients undertook an attempt of smoking cessation. Nicotine replacement therapy (NRT) or bupropion was prescribed in 51% of the attempts. Sixty-four sustained quitters were counted after 6 months (29%), 43 after 1 year (19%) and 33 after 2 years (15%). We found a small but statistically non-significant difference in success rate in favour of the group that underwent office spirometry. CONCLUSION: GPs can motivate almost 20% of their smoking population to quit smoking. The success rate with the minimal intervention strategy was 19% after 1 year and 15% after 2 years. We found no arguments in favour of confronting smokers with their lung function as a tool for enhancing smoking cessation.