Smoking Cessation : Treatment Intensity and Outcome in Randomized Clinical Trials

The primary aim was to compare the effectiveness of smoking cessation interventions of different intensities in a clinical dental and a telephone setting in Sweden. Methods: A total of 300 smokers were randomized to High or Low Intensity Treatment (HIT or LIT) at the Public Dental Service, County Council of Västmanland. Effectiveness (abstinence rate) was measured after 1yr (paper I) and 5-8yrs (paper III). A cost-effectiveness analysis was conducted, based on intervention costs, number of abstinent participants after 1yr, and a Markov modelling of future costs and health (in QALYs) consequences (paper II). In paper IV, 586 callers to the Swedish National Tobacco Quitline (SNTQ) were randomized to high-intensity proactive or low-intensity reactive service, and effectiveness was measured after 1 yr. Effectiveness measures were self-reported point prevalence, 6-month continuous abstinence, and sustained abstinence. Results: Absolute quit rates were 7% higher with HIT than with LIT on all measures and increased by 8% from 1yr to 5-8yrs. Point prevalence was 23% vs. 16% (p=.11) after 1yr and 31% vs. 24% (p=.16) after 5-8yrs. Six-month continuous abstinence was 18% vs. 9% (p =.02) after 1yr and 26% vs.19% (p=.18) after 5-8yrs. Sustained abstinence was 12% vs. 5% (p =.03) after 5-8yrs. Nicotine dependence was a strong predictor for abstinence at 1yr and achieved abstinence at 1yr was a strong predictor for abstinence at long-term follow-up. The cost-effectiveness analysis showed that both HIT and LIT were cost-effective, and LIT was even cost-saving compared with doing nothing. HIT was more costly and more effective than LIT, and the cost of each extra QALY gained by HIT was 100,000SEK, which is considered very cost-effective in Sweden. Proactice and reactive services were equally effective at the SNTQ. Point prevalence was 27% and 6-month continuous abstinence was 21% after 1yr. Being smoke-free at baseline was the strongest predictor for abstinence at 1yr. Conclusion: Support at high as well as low intensity in a clinical dental setting in Sweden and at the SNTQ was effective in achieving smoking cessation. Both high- and low-intensity interventions were very cost-effective in a clinical dental setting