|Varenicline as compared to bupropion in smoking-cessation therapy: cost-utility results for Sweden 2003
|Bolin K, Mork A C, Willers S, Lindgren B
This is a critical abstract of an economic evaluation that meets the criteria for inclusion on NHS EED. Each abstract contains a brief summary of the methods, the results and conclusions followed by a detailed critical assessment on the reliability of the study and the conclusions drawn.
This study examined the cost-effectiveness of varenicline in comparison with bupropion in smoking-cessation programmes for smokers aged 18 years or older. The authors concluded that varenicline was a cost-effective alternative to bupropion in Sweden. The study was based on robust methodology, which enhances the validity of the authors’ conclusions.
Type of economic evaluation
This study examined the cost-effectiveness of varenicline in comparison with bupropion in smoking-cessation programmes for current smokers aged 18 years or older.
The two pharmacological treatments were varenicline, for 12 weeks, compared with bupropion, for seven weeks.
This economic evaluation was based on a previous model, called the Benefits of Smoking Cessation on Outcomes (BENESCO), with time-horizons of 20 and 50 years. The authors adopted the perspectives of both the health care system and society.
The clinical inputs were derived from a selection of known, relevant studies. Most of the epidemiological data were derived from Swedish administrative sources. The treatment efficacy, which was the key input, was derived from pooled data from two identically designed, head-to-head trials with one-year follow-ups. The long-term risk of morbidity (chronic obstructive pulmonary disease, coronary heart disease, stroke, and lung cancer), mortalities, and risk of relapse were taken from other published studies, the details of which were not given, and supplemented by authors’ assumptions. The key model input was the probability of smoking cessation with the two treatments.
Monetary benefit and utility valuations:
The utility values were derived from several published studies and were already incorporated in the previous model.
Measure of benefit:
Quality-adjusted life-years (QALYs) were the summary benefit measure and were discounted at 3% per annum.
The economic analysis included intervention costs (drugs, general practitioner visits, and motivational support provided by a nurse) and health care costs avoided for four diseases, which were chronic obstructive pulmonary disease, coronary heart disease, stroke, and lung cancer. These costs were derived from a Swedish county database which was considered to be representative of the national population. The resource use was based on general recommendations and Swedish clinical practice. The indirect effect of smoking cessation on production and consumption in the economy were also considered and were derived from a published study. The price year was 2003 and a 3% annual discount rate was applied. All costs were presented in Euros (EUR).
Analysis of uncertainty:
Both a deterministic and a probabilistic analysis were carried out to investigate the uncertainty of the base-case findings. The probabilistic analysis considered three variables: treatment efficacy, morbidity-related health care costs, and utility weights. The alternative values used in the deterministic analysis appear to have been based on the authors’ judgement, except for some clinical data, which were derived from published confidence intervals.
At 20 years, in 2003, in Sweden, in the eligible population of 168,844 men, varenicline produced EUR 5,458,518 in incremental intervention costs, averted EUR 13,196,719 in health care costs, added EUR 13,065,853 in indirect costs, and gained 2,591 QALYs in comparison with bupropion, resulting in an incremental cost per QALY gained of EUR 2,056.
In the eligible population of 208,737 women, varenicline produced EUR 6,748,210 incremental intervention costs, averted EUR 16,206,542 in health care costs, added EUR 12,386,576 in indirect costs, and gained 2,455 QALYs in comparison with bupropion, resulting in an incremental cost per QALY gained of EUR 1,193.
Over a 50-year time horizon, the incremental cost per QALY gained was EUR 14,743 for men and EUR 14,214 for women.
When the indirect effects were excluded, for both time horizons, varenicline was the dominant strategy, which means it was simultaneously less expensive and more effective than bupropion.
The sensitivity analysis generally showed that these base-case findings were robust. The most influential model inputs were the treatment efficacy and intervention costs.
The authors concluded that varenicline was a cost-effective alternative to bupropion as a smoking cessation intervention in Sweden.
The authors justified their selection of the interventions. Bupropion appears to have been the relevant comparator for the new non-nicotine-based varenicline, but the dosages were not reported.
The clinical data came from a selection of sources, which was intended to identify the most relevant data. National databases were chosen to reflect the Swedish epidemiological setting, while the treatment efficacy was based on pivotal trials. Thus, an appropriate selection of data appears to have been made. One weakness of the clinical data was the lack of information given on these sources, but some of the data were already incorporated in the previous model. No details on the derivation of the utility valuations were presented. The types of instrument used in the source studies to elicit these preferences and from whom were not reported. QALYs appear to have been appropriate for this patient population, given the impact of the disease on both the quality of life and survival.
The types of costs reflected the economic perspective. The expected costs were presented with and without indirect costs, which makes the conclusions relevant to different payers. A breakdown of cost items was presented only for the intervention, while those costs associated with the diseases were presented as macro-categories. The price year was reported and currency conversions were appropriately performed. The sources of data reflected the Swedish setting, and were reported, but not described in detail, particularly with respect to the indirect costs.
Analysis and results:
The costs and benefits were synthesised using an incremental approach, which was appropriate. The expected costs and benefits were clearly presented. The issue of uncertainty was appropriately addressed and the findings of the sensitivity analyses were extensively reported although they were not discussed in depth.
This study was based on robust methodology, which enhances the validity of the authors’ conclusions.
Supported and funded by Pfizer AB, Sweden.
Bolin K, Mork A C, Willers S, Lindgren B. Varenicline as compared to bupropion in smoking-cessation therapy: cost-utility results for Sweden 2003. Respiratory Medicine 2008; 102(5): 699-710
Other publications of related interest
Hoogendoorn M, Welsing P, Rutten-van Molken M. Cost-effectiveness of varenicline compared with bupropion, NRT, and nortriptyline for smoking cessation in the Netherlands. Curr Med Res Opin 2008;24:51-61.
Bolin K, Lindgren B, Willers S. The cost utility of bupropion in smoking cessation health programs—simulation model results for Sweden. Chest 2006;129:651-60.
Gonzales D, Rennard SI, Nides MA, et al. Varenicline, an α4β2 nicotinic acetylcholine receptor partial agonist, vs bupropion and placebo for smoking cessation: a randomized controlled trial. JAMA 2006;296:47-55.
Jorenby DE, Hays JT, Rigotti NA, et al. A randomized controlled trial comparing the efficacy of varenicline, a novel α4β2 nicotinic acetylcholine receptor partial agonist, to bupropion and to placebo for smoking cessation. JAMA 2006;296:56-63.
Subject indexing assigned by NLM
Adolescent; Adult; Aged; Benzazepines /economics /therapeutic use; Bupropion /economics /therapeutic use; Cost of Illness; Cost-Benefit Analysis; Dopamine Uptake Inhibitors /economics /therapeutic use; Female; Health Care Costs; Humans; Male; Middle Aged; Models, Econometric; Morbidity; Quality-Adjusted Life Years; Quinoxalines /economics /therapeutic use; Smoking Cessation /economics /methods /psychology; Sweden; Value of Life; Varenicline
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