Continued smoking abstinence in diabetic patients in primary care: a cluster randomized controlled multicenter study

To assess the effectiveness of an intensive smoking cessation intervention based on the transtheoretical model of change (TTM) in diabetic smokers attending primary care.

A cluster randomized controlled clinical trial was designed in which the unit of randomization (intervention vs. usual care) was the primary care team. An intensive, individualized intervention using motivational interview and therapies and medications adapted to the patient's stage of change was delivered. The duration of the study was 1 year.

A total of 722 people with diabetes who were smokers (345 in the intervention group and 377 in the control group) completed the study. After 1 year, continued abstinence was recorded in 90 (26.1%) patients in the intervention group and in 67 (17.8%) controls (p=0.007). In patients with smoking abstinence, there was a higher percentage in the precontemplation and contemplation stages at baseline in the intervention group than in controls (21.2% vs. 13.7%, p=0.024). When the precontemplation stage was taken as reference (OR=1.0), preparation/action stage at baseline showed a protective effect, decreasing 3.41 times odds of continuing smoking (OR=0.293 95% CI 0.179-0.479, p<0.001). Contemplation stage at baseline also showed a protective effect, decreasing the odds of continuing smoking (OR=0.518, 95% CI 0.318-0.845, p=0.008).

An intensive intervention adapted to the individual stage of change delivered in primary care was feasible and effective, with a smoking cessation rate of 26.1% after 1 year.