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Research overview

Cost-effectiveness of varenicline, bupropion and nicotine replacement therapy for smoking cessation

We were commissioned to evaluate the cost-effectiveness of drugs for smoking cessation in a Norwegian setting. The economic evaluation will inform the revised treatment guideline for smoking cessation in primary care.


  • Issued/Revised: 2010
  • Hagen G, Wisløff T, Klemp M. Cost-effectiveness of varenicline, bupropion and nicotine replacement therapy for smoking cessation. Research overview 2010. ISBN (digital): 978-82-8121-341-8, ISSN (digital): 1890-1298. Available at www.fhi.no/en

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Key message

Background
Smoking is an important risk factor for several diseases, including different cancers, lung diseases and cardiovascular diseases. About 21% of the Norwegian population are daily smokers.  

Interventions for smoking cessation are normally divided into counselling and drug treatment support. In Norway, two prescription drugs are available for use in smoking cessation; varenicline (Champix ® or Chantix ®) and bupropion (Zyban ®). In addition, several options for nicotine replacement therapy are available, such as nicotine-gum, patches and lozenges.

Commision
We were commissioned to evaluate the cost-effectiveness of drugs for smoking cessation in a Norwegian setting. The economic evaluation will inform the revised treatment guideline for smoking cessation in primary care.

Main findings

  • Compared to no treatment, nicotine replacement therapy, bupropion and varenicline can all be considered cost-effective.
  • When the drugs are evaluated relative to each other, varenicline is the most cost-effective alternative.

Summary

Background
Smoking is an important risk factor for several diseases, including different cancers, lung diseases and cardiovascular diseases. About 21% of the Norwegian population are daily smokers.  Interventions for smoking cessation are normally divided into counselling and drug treatment support. In Norway, two prescription drugs are available for use in smoking cessation; varenicline (Champix ® or Chantix ®) and bupropion (Zyban ®). In addition, several options for nicotine replacement therapy (NRT) are available, such as nicotine-gum, patches and lozenges. These do not require a prescription from a doctor.

We were commissioned to evaluate the cost-effectiveness of drugs for smoking cessation in a Norwegian setting. The economic evaluation will inform a revised treatment guideline for smoking cessation in primary care.

Method
We preformed a model based economic evaluation of nicotine replacement therapy (NRT), bupropion and varenicline for smoking cessation. The drugs were compared to placebo and to each other.

We constructed a Markov model with the health states “smoker”, “smoke free more than five years (ex smoker)”, “smoke free less than five years (quitter)”, “resumed smoking less than five years ago” and “dead”. A Markov model follows a hypothetical cohort of patients over time, in our model we followed the individuals from a variable age at treatment initiation and until they all were dead or 100 years old.  In the first year of the model, the individuals received treatment with NRT, bupropion or varenicline or they received no treatment. The efficacies of the treatments were collected from our systematic review of the literature. The model calculated the life years gained and the costs associated with pharmacological treatments for smoking cessation.

Results
The baseline results presented in this part are for a 50 years old male. Sensitivity analyses indicate that smoking cessation is slightly more cost-effective for men than for women and for younger compared to older people, but the differences are so small that conclusions will not be affected.

When NRT, bupropion and varenicline are each compared to placebo, they will respectively yield 0.02, 0.09 and 0.14 additional life years, at an additional  cost of respectively NOK 4 141, NOK 5 729  and NOK  9 672. The net health benefit (NHB) of nicotine replacement therapy (NRT), bupropion and varenicline compared to placebo then becomes respectively 0.012, 0.079 and 0.121.

All treatments have a positive net health benefit and can be considered cost-effective compared to placebo assuming a Norwegian threshold value of NOK 500 000 per life year gained. NRT is however extendedly dominated by bupropion, as the incremental cost-effectiveness ratio (ICER) for NRT is higher than the ICER for bupropion, the second most effective alternative. The implication of this is that if the NRT alternative were to be chosen, effectiveness would be bought at a higher marginal cost than necessary.

When several treatment options are available and they are mutually exclusive, treatments should be compared to the next more effective option. We therefore ordered the treatments according to increasing effectiveness and recalculated the incremental costs and effects. Since NRT was excluded based on extended dominance, bupropion was compared to no treatment and varenicline to bupropion.  Compared to bupropion, varenicline gives 0.05 additional life years at an additional cost of 3 944. The incremental cost-effectiveness ratio of varenicline compared to bupropion is NOK 78 880 per life year gained, giving a net health benefit of 0.042 life years. When the drugs are evaluated relative to each other, varenicline is the most cost-effective option.

The one-way sensitivity analyses indicate that the base case results are most sensitive to changes in age at treatment initiation, the price of varenicline, average health care expenses per person per year and choice of discount rate. None of the changes in the parameters will bring the ICER above the assumed willingness to pay per life year of NOK 500 000.

In the probabilistic sensitivity analysis, varenicline was the optimal choice in terms of cost-effectiveness as long as the willingness to pay per life year gained was above NOK 116 000. If the willingness to pay was between NOK 100 000 and NOK 116 000, bupropion was optimal. If the willingness to pay was less than NOK 100 000 per life year gained, none of the treatments could be considered cost-effective.

In the base case we assumed that smokers and ex-smokers had the same annual health care costs and that health care costs were constant across age. This may not be a valid assumption. We therefore constructed a scenario analysis based on Danish data where smokers had higher annual health care costs than the ex-smokers and where annual health care costs varied with age. In the scenario analysis all treatment options were dominant, i.e. more effective and less expensive than no treatment. Treatment with varenicline gave the highest health gains in terms of life years and also the largest savings.

The analysis on perfect information on parameters indicated that perfect information on the input parameters would not reduce the uncertainty in the decision, given the assumed willingness to pay of NOK 500 000 per life year gained.

Discussion
All models are simplifications of reality; hence, there is uncertainty associated with the results. Some of the uncertainty is related to the model input, i.e. the parameter estimates used. Our model input has been gathered from a range of sources and they may not on their own represent true values for a Norwegian population in a real-life setting. We have however conducted a range of sensitivity analyses on these parameters and the conclusions appear robust to realistic changes in these values.

Another aspect of uncertainty is connected to the model structure. This model was structured to capture the life years gained from smoking cessation. The model therefore only contains the health states necessary to capture costs and health effects of being either dead or alive. In reality however, smoking will increase the risk of a variety of diseases, most notably different cancers, lung diseases and cardiovascular diseases. These diseases can lead to large reductions in health related quality of life. It is therefore possible that we are underestimating the cost-effectiveness of these drugs.

The published economic evaluations we have identified come to the same conclusion as we have. Some of the studies do, however, find that varenicline is dominant (higher health gains and lower costs) compared to bupropion. In our base case analyses, varenicline have higher health gains, but do not have lower costs than bupropion. In our scenario analysis where smokers are more expensive than ex-smokers, we do however find that varenicline is dominant compared to bupropion.

Conclusion
Nicotine replacement therapy (NRT), bupropion and varenicline can be considered cost-effective compared to placebo. When the drugs are evaluated relative to each other, varenicline is the most cost-effective alternative.

This is a publication from the Norwegian Knowledge Centre for the Health Services. The Knowledge Centre became part of the Norwegian Institute of Public Health 01/01/2016.

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