A randomized controlled trial of a tailored intervention compared to usual care to promote smoking cessation and improve glycaemic control on type 2 diabetic patients who smoked

Abstract

Background: Tobacco smoking not only leads to adverse health problems but also undesirable complications for smokers with diabetes mellitus (DM). Providing brief smoking cessation advices to diabetic smokers should be a part of standard care. More rigorous empirical evidence of its effectiveness is required. This study aimed to investigate the effect of a brief stage-matched smoking cessation intervention in enhancing glycemic control and smoking abstinence for type 2 DM smokers in Hong Kong. Methods: This was a large randomized controlled trial with 557 type 2 DM smokers randomized into an intervention group (n=283) to receive brief individualized face-to-face stage-matched smoking cessation counseling (around 20 minutes) by a trained smoking cessation nurse counsellor and a diabetes-specific smoking cessation leaflet, or a control group (n=274) who received usual care. Subjects were then followed up at 1 week, 1 month, 3 months, 6 months, and 12 months by telephone and assessed for smoking status. Results: Above 70% of the subjects were in the pre-contemplation stage of quitting smoking. On average, they smoked 14 cigaretes per day for over 37 years. By intention to treat analysis, both intervention and control groups had similar 7-day point-prevalence smoking abstinence (9.2% vs. 13.9%, p = 0.08), biochemically validated quit rates (3.2% vs. 5.1%, p = 0.25), and HbA1c level (7.95% [63 mmol/mol] vs. 8.05% [64 mmol/mol], p = 0.49) at 12 months. Although the control group had a statistically significantly higher rate of self-reported smoking reduction by at least 50% than the intervention group at 3 months (excluding quitters in numerator: 16.8% vs. 10.2%, p = 0.02; excluding quitters in both numerator and denominator: 18.5% vs. 11.1%, p = 0.02), no significant differences were observed between the two groups at the 6-(excluding quitters in numerator: 13.4% vs. 14.2%, p = 0.78; excluding quitters in both numerator and denominator 16.1% vs. 15.1%, p = 0.77) and 12-month follow-ups (excluding quitters in numerator : 14.8% vs. 14.6%, p = 0.94; excluding quitters in both numerator and denominator: 17.0% vs. 16.3%, p = 0.84). Conclusion: The results showed that a brief stage-matched smoking cessation intervention was not effective in increasing the rates of quitting or smoking reduction in DM patients who smoked. The intervention was also not effective in improving glycemic control. The quit rate was very low, suggesting that most of these patients were hardcore smokers. More RCTs on more intensive interventions are needed to motivate DM patients to quit smoking. Project Number: 08091061