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- Discussion and Conclusions
Objectives: To estimate the cost-effectiveness of five face-to-face smoking cessation interventions (i.e., minimal counseling by a general practitioner (GP) with, or without nicotine replacement therapy (NRT), intensive counseling with NRT, or bupropion, and telephone counseling) in terms of costs per quitter, costs per life-year gained, and costs per quality-adjusted life-year (QALY) gained.
Methods: Scenarios on increased implementation of smoking cessation interventions were compared with current practice in The Netherlands. One of the five interventions was implemented for a period of 1, 10, or 75 years reaching 25% of the smokers each year. A dynamic population model, the RIVM chronic disease model, was used to project future gains in life-years and QALYs, and savings of health-care costs from a decrease in the incidence of 11 smoking-related diseases over a time horizon of 75 years. This model allows the repetitive application of increased cessation rates to a population with a changing demographic and risk factor mix. Sensitivity analyses were performed for variations in costs, effects, time horizon, program size, and discount rates.
Results: Compared with current practice, minimal GP counseling was a dominant intervention, generating both gains in life-years and QALYs and savings that were higher than intervention costs. For the other interventions, incremental costs per QALY gained ranged from about 1100‰ for telephone counseling to 4900‰ for intensive counseling with nicotine patches or gum for implementation periods of 75 years.
Conclusions: All five smoking cessation interventions were cost-effective compared with current practice, and minimal GP counseling was even cost-saving.
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- Discussion and Conclusions
Smoking is a leading cause of preventable morbidity and mortality. It incurs high costs to the society. The World Bank estimated that 6% to 15% of total health-care costs were attributable to smoking in high-income countries .
For many smokers, it is hard to quit smoking on will power alone. Only 3% to 7% of the smokers who attempt to stop smoking on will power are still abstinent after 1 year [2,3]. A wide range of policy measures and therapies is available to increase this rate, varying from price increases by taxation, media campaigns, or self-help manuals, to intensive individual counseling combined with pharmaceutical therapies. For smoking cessation interventions administered by medical professionals, the percentage of sustained quitters ranges from 7% to 24%[4–6].
Reviews of the cost-effectiveness of smoking cessation interventions [7–9] show that the costs of these interventions are relatively low compared with the resulting gains in terms of avoided mortality, morbidity, and costs of care for smoking-related diseases. Costs per life-year gained varied between about 200‰ and 10,000‰ when converted into Dutch currency using purchasing power parity rates  and updated to the year 2000 with consumer price indices. The majority of studies reported cost-effectiveness ratios around 2500‰ per life-year gained [7–9,11–23]. These figures should be interpreted very carefully, because the transfer of results from economic studies between countries is difficult. None of these studies included savings in costs of care from avoided smoking-related morbidity or took account of the fact that former smokers may restart smoking after more than 12 months of continuous abstinence.
The present study aims to examine cost-effectiveness for a specific set of smoking cessation interventions, i.e., face-to-face smoking cessation interventions administered by professionals with proven effectiveness in terms of cessation rates. Five different cessation interventions (i.e., minimal counseling by a general practitioner (GP) with, or without nicotine replacement therapy (NRT), intensive counseling with NRT, or bupropion, and telephone counseling) were compared with current practice to report cost-effectiveness ratios for different implementation periods. The selection of interventions was driven by the fact that the study was initiated by the Dutch Public–Private Partnership to reduce tobacco dependence to support them in developing Dutch smoking cessation guidelines for healthcare professionals. Therefore, we selected interventions that are currently applied in The Netherlands. A computer simulation model was used to project the future gains in life-years, QALYs, and the savings in health-care costs that result from a decrease in the incidence of smoking-related diseases, over a time horizon of 75 years. The strength of the model is that it is dynamic, allowing us to apply increased cessation rates on a repetitive basis to a population whose mix of age, sex, and smoking prevalence changes annually.
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- Discussion and Conclusions
For each intervention applied to a population of 1000 smokers, Table 5 presents the total number of extra quitters, additional intervention costs as well as costs per quitter, compared with the 34 quitters that would be obtained in current practice. Costs per quitter ranged from about 450‰ for minimal GP counseling to about 3000‰ for intensive counseling with nicotine patches or gum.
Table 5. Number of additional quitters, total additional intervention costs, and costs per quitter for the intervention scenarios compared with the current practice scenario for a group of 1000 smokers (euros, year 2000 price level)
|Intervention||Additional quitters*||Additional intervention costs† (×1000)||Costs per quitter|
|TC|| 42|| 69||1640|
|MC|| 45|| 20|| 450|
|MC + NRT|| 93||162||1750|
|IC + NRT||117||348||2970|
|IC + Bupr||138||333||2410|
Table 6 shows the model estimates of health effects and health-care costs for the Dutch population when the smoking cessation interventions were offered for a period of 1, 10, and 75 years. The table presents in the first two columns cumulative discounted health effects, first the extra life-years gained from a reduced mortality and second the extra QALYs gained. The third column gives the net present value of intervention costs. Combining these, the fourth and the fifth column present intervention costs per life-year and QALY gained, respectively. The sixth column then gives the savings in health-care costs from a reduced prevalence of smoking related diseases. Finally, the last two columns present the cost-effectiveness ratios in terms of costs per life-year or QALY gained.
Table 6. Number of life-years and QALYs gained, total additional intervention costs, intervention costs per LY and QALY gained, total savings in costs of care and cost-effectiveness: costs per life-years gained and costs per QALY gained for the different scenarios cumulative for three different time periods, discounted at 4% for both costs and effects (euros, year 2000 price level)
|Intervention||LYs gained* (×104)||QALYs gained† (×104)||Intervention costs‡ (×109)||Intervention costs per LY gained||Intervention costs per QALY gained||Savings of treatment for diseases§ (×10 9)||Costs per LY gained||Costs per QALY gained|
|TC|| 1.2|| 1.6||0.077|| 6,200||4800||0.053||2000||1500|
|MC|| 1.4|| 1.7||0.023|| 1,700||1300||0.057||¶||¶|
|MC+NRT|| 2.8|| 3.6||0.18|| 6,500||5000||0.12||2300||1700|
|IC+NRT|| 3.5|| 4.5||0.39||11,000||8500||0.15||6800||5200|
|IC+Bupr|| 4.1|| 5.3||0.37|| 8,900||6900||0.17||4700||3600|
|TC||11|| 14||0.64|| 5,800||4500||0.46||1600||1200|
|MC||12|| 15||0.19|| 1,600||1300||0.50||¶||¶|
|MC + NRT||23|| 30||1.4|| 6,200||4800||0.98||1900||1500|
|IC + NRT||29|| 37||3.0||10,500||8100||1.2||6300||4900|
|IC + Bupr.||33|| 43||2.8|| 8,600||6600||1.4||4400||3400|
|TC||31|| 38||1.7|| 5,700||4600||1.3||1400||1100|
|MC||33|| 41||0.52|| 1,600||1300||1.4||¶||¶|
|MC + NRT||62|| 78||3.8|| 6,100||4800||2.7||1800||1400|
|IC + NRT||74|| 94||7.8||10,500||8300||3.2||6200||4900|
|IC + Bupr||84||110||7.3|| 8,600||6800||3.6||4300||3400|
Minimal GP counseling was a dominant strategy compared with current practice, regardless of the implementation period. For minimal GP counseling about 330,000 life-years or 410,000 QALYs were gained with a 75 years implementation period. About 1.4‰ billion in health-care costs for smoking-related diseases were saved and these savings were higher than the intervention costs of about 520‰ million. The four other interventions yielded higher costs than savings and cost-effectiveness ratios that ranged from 1100‰ per QALY for telephone counseling to 4900‰ for intensive counseling with NRT. For a 75-year implementation period, the absolute gain in life-years and QALYs and the savings in costs for not having to treat smoking-related diseases were highest, but the intervention costs were also highest. The 1- and 10-year intervention scenarios showed lower total intervention costs as well as lower savings, gains in life-years, and QALYs than permanent implementation. The cost-effectiveness ratios were not very much affected by the duration of the implementation period.
Effects and Costs over Time
The current practice scenario projected a decline in smoking. The percentage of smokers in the Dutch population aged 10 years and older decreased from 32% in 2000 to 25% in 2075. Smoking prevalence increased in older women, but decreased in men of all ages and in young women. For the youngest age groups of both men and women, the decline was quite small. For the intervention scenarios reaching 25% of the smokers, the percentage of smokers declined to 21% in 2075 for permanent implementation of intensive counseling with bupropion at maximum. For the intervention scenarios of 1- and 10-year implementation periods, effects on the number of smokers gradually disappeared after the intervention stopped because of relapse and new young smokers, and the percentage of smokers in 2075 was 25%, the same as in the current practice scenario. In all scenarios, a lag time between an increased implementation of smoking cessation interventions and the full gain in life-years and QALYs could be observed. After implementation, first the number of quitters increases, decreasing the number of smokers and increasing the number of former smokers. This leads to a reduced incidence of smoking-related diseases and hence a reduced prevalence. In turn, that causes a reduced mortality. Reduced mortality is counted as life-years gained. The combined reduction in prevalence and mortality gives the QALY gain. For 1- and 10-year implementation periods, reductions in mortality reach a top, about 15 and 20 years after implementation, respectively, then the gain compared with current practice declines again, to nearly zero, about 65 years after implementation, so that the full gain is obtained within the model's time horizon.
Figure 1 depicts the uncertainty in resource use and effectiveness. It presents gains in total costs, including savings from reductions in the incidence of 11 smoking-related diseases, and QALYs plus uncertainty ranges over resource use and cessation rates, for permanent (i.e., 75 years) implementation of the smoking cessation interventions compared with current practice. Changes in cessation rates led not only to changes in QALYs gained but also to changes in the incidence of smoking-related diseases and hence to changes in total additional costs. This explains why the horizontal confidence lines in Figure 1 were not completely horizontal, but slightly diagonal. The relatively large uncertainty about the effectiveness of minimal GP counseling was reflected by the relatively wide horizontal uncertainty range. Nevertheless, the result that minimal GP counseling is a cost-saving intervention was robust for uncertainties in resource use and effects. The figure shows that uncertainty ranges overlapped, so that the dominance of intensive counseling with bupropion over intensive counseling with NRT was quite uncertain, while that of minimal GP counseling over telephone counseling was also uncertain. Besides, because of the large uncertainty range in costs, it might well be that minimal counseling with NRT was also dominated by either intensive counseling with NRT or intensive counseling with bupropion. Cost-effectiveness ratios became more favorable when the time horizon increased, so that more of the gains were included. Minimal GP counseling was dominant for all time horizons considered. For intensive counseling with bupropion, costs per QALY gained ranged from about 13,000‰ for a time horizon of 20 years to 3900‰ for a time horizon of 50 years, compared with 3400‰ for a time horizon of 75 years. Cost-effectiveness ratios were not sensitive to changes in the percentage of smokers that was offered the intervention, which ranged from 10% to 50% of all smokers. Table 7 shows incremental cost-effectiveness ratios for different discount rates for costs and effects, compared with current practice, for 75-year intervention scenarios. Discounting clearly affected the cost-effectiveness ratios, reducing the impact of both future savings in health-care costs and future health effects. To illustrate the effect of discounting, a life-year gained 75 years from now weights for full if health effects are not discounted, while it weights for 0.11, 0.053, or 0.026 if health effects are discounted at 3%, 4%, or 5%, respectively. Because health effects occur with a delay, while intervention costs start immediately, the effect of higher discount rates will be that the net present values of health effects, and related savings in health-care costs decrease, while the net present value of intervention costs decreases much less. As a result, cost-effectiveness ratios become worse as the discount rate increases.
Figure 1. Total additional costs and total quality-adjusted life-years (QALYs) gained for the intervention scenarios compared with current practice with the range in costs and effects based on the sensitivity analyses, cumulative for the years 2000–2075. TC, telephone counseling; MC, minimal GP counseling; MC + NRT, minimal GP counseling combined with nicotine patches or gum; IC + NRT, intensive counseling combined with nicotine patches or gum; IC + Bupr, intensive counseling combined with bupropion.
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Table 7. Incremental costs per QALY gained for the intervention scenarios for different discount rates for both costs and effects, cumulative for the time period 2000–2075 (euros, year 2000 price level)
|Intervention||Costs per QALY for different discount rates|
|Discount rate for costs and effects 3%||Discount rate for costs and effects 5%||Discount rate for costs 4% and for effects 0%||Discount rate for costs and effects 0%|
|TC|| 720||1600|| 240|| 10|
|MC + NRT|| 990||2000|| 310|| 210|
|IC + NRT||4000||5900||1,000||2,300|
|IC + Bupr||2700||4200|| 730||1,400|
Discussion and Conclusions
- Top of page
- Discussion and Conclusions
In conclusion, when assessing the cost-effectiveness of five face-to-face smoking cessation interventions, we found that minimal GP counseling was cost-saving compared with current practice, whereas the cost-effectiveness ratios of minimal counseling plus nicotine replacement therapy, intensive counseling with nicotine replacement therapy, intensive counseling with bupropion, and telephone counseling were quite small. Implementation of these interventions on a permanent basis for 25% of all smokers resulted in estimated cost-effectiveness ratios that ranged from 1400‰ per life-year or 1100‰ per QALY gained for telephone counseling to 6200‰ per life-year or 4900‰ per QALY gained for intensive counseling in combination with NRT.
The cost-effectiveness ratios were sensitive to the rate of discount, the time horizon, resource use estimates, and cessation rates. Nevertheless, the cost-effectiveness ratios remained rather low for the variations in the discount rate, time horizon, cessation rates, and resource use that were analyzed in the sensitivity analyses. The ratios did not vary much with the percentage of smokers reached or the length of the implementation period.
For several reasons the ratios above were conservative estimates of the cost-effectiveness. The effects of smoking cessation on the course of diseases were not included, nor were the effects of passive smoking and the effects of smoking cessation by pregnant women on the health of their future infants.
Furthermore, savings from reduced productivity losses were not included. Finally, it should be noted that a large part of the future effects of the intervention efforts during the last 15 to 20 years of the permanent implementation scenario were not taken into account, because these health gains occurred outside the model's time horizon of 75 years. For the 1- and 10-year implementation scenarios, all health gains occurred within the time horizon, and this bias was avoided.
In contrast, three reasons why our results may overestimate cost-effectiveness ratios must be mentioned. First, the estimates of effectiveness were obtained from clinical trials. If trial populations were a selection of motivated smokers, our cessation rates would be too high. This applies in particular to the more intensive interventions but less to minimal GP counseling with, or without NRT, and telephone counseling, because for the latter interventions, trials were often done in an unselected group of smoking GP patients. The second is that the model did not include a delay effect of smoking cessation, i.e., all quitters received the lower relative risks of disease incidence of former smokers the year after quitting. However, the estimates of the relative risks in our model were conservative. Relative risks of former smokers were estimated as an average of the relative risks of all former smokers regardless of how long ago they had stopped. This implies that for the first years after quitting the reduction in relative risk in our model was too high, while for later years it was too low. Third, in contrast with most cost-effectiveness analyses of smoking cessation, we took savings of avoided smoking-related diseases into account. Health-care costs unrelated to smoking in life-years gained from smoking cessation, for instance, costs of care for dementia, were ignored in our computations. Whether or not costs of care for diseases not related to smoking (so-called unrelated medical costs) that occur during added years of life should be included in cost-effectiveness analyses is a topic of discussion in the literature [55–57]. The current convention in economic evaluation is to ignore unrelated medical costs. Indeed, textbooks and guidelines [54,55] recommend the exclusion of medical costs during life-years gained, unless there is a causal relationship between the intervention and these costs. It was recently argued that it is theoretically more sound to include the survivor costs (i.e., general costs of care that occur during the added years of life) if they present resources that directly produce the utility that is being measured in the denominator of the cost-effectiveness ratio . In practice, most cost-effectiveness analyses exclude unrelated costs of care, partly for reasons of data availability. Given current guidelines and to enable comparison with other cost-effectiveness analyses, in the present study these unrelated medical costs were also excluded.
To have very conservative estimates of the cost-effectiveness ratios, we also computed the ratio of intervention costs to the difference in QALYs or life-years, and presented them in Table 6. Intervention costs per life-year gained varied from about 1,600‰ for minimal GP counseling to 10,500‰ for intensive counseling combined with NRT for 75-year implementation periods.
Our study differs from other cost-effectiveness analyses of smoking cessation, because we used a dynamic population model. We did not model a closed cohort of smokers until their death, as most studies do [14,16,19,23,58], but estimated effects for the Dutch population. The model included relapse after 12 months continuous abstinence and inflow of new young smokers. Not all smokers who quit in the 1-year scenario would remain nonsmokers for the whole time horizon. This led to higher cost-effectiveness ratios than would be obtained if restart rates were ignored. In addition, the model takes account of the demographic changes in the population and the changes in incidence and prevalence of the risk factor of smoking and the smoking-related diseases.
Furthermore, we could model 10- and 75-year implementation periods and compare these to a 1-year implementation. Our finding that the implementation period did not much affect the cost-effectiveness ratios was partly influenced by the simplifications that had to be made to keep the model tractable and use reliable input data. Cessation rates were assumed constant over time, and smokers, as well as former smokers, were modeled as homogeneous groups with average age- and sex-specific cessation rates and restart rates, respectively, ignoring smokers’ individual quit and relapse history. If cessation and restart rates would depend on the number of previous quit attempts, this would influence the outcomes in longer implementation periods. Inclusion of this, however, would strongly complicate the model, while reliable input data were not available.
Despite the methodological differences, our cost-effectiveness ratios were within the range of values found in the literature. Converting all outcomes into Dutch currency for the year 2000, values in the literature varied from 200‰ to 10,000‰ per life-year gained [8,9,12–23]. Our result that costs per life-year gained of intensive counseling with bupropion were more favorable than those of intensive counseling with NRT was in line with former research [7,9,11].
Comparing the results for the five interventions to each other, two interventions were relatively cheap: minimal GP counseling and telephone counseling. But they were also less effective than the other interventions. The effectiveness of minimal GP counseling was based on a single Dutch trial . This was reflected by the large uncertainty range. We choose this trial instead of a Cochrane meta-analysis on physician counseling , because we felt that the 11 studies on minimal counseling included in the meta-analysis did not sufficiently reflect the Dutch minimal GP counseling. The finding that minimal GP counseling is cost-saving, however, was robust. Two other interventions, intensive counseling combined with either NRT or bupropion were more expensive, but they were also more effective. Although their cost-effectiveness ratios were higher than the ratios of minimal GP counseling and telephone counseling, they remained low. For these interventions, costs were more difficult to estimate, because of variations in the duration and intensity of counseling and the duration of NRT use. The costs of one intervention, minimal GP counseling combined with NRT, fell in between. However, its costs were highly uncertain, resulting in an uncertainty range that goes from slight cost savings up to high additional costs. This was in line with results from the Cochrane meta-analysis  that stated that the added effect of NRT to low intensity counseling was hard to prove. The trials included in this meta-analysis showed a high variance in the duration of NRT, mainly because of differences in compliance.
The cost-effectiveness ratios, even for the most resource intensive cessation interventions were well below many other commonly recommended medical and surgical interventions. This highlights the cost-effectiveness of smoking cessation interventions, which affects many smoking-related diseases.
How favorable the cost-effectiveness ratios are can be demonstrated by comparing them with other preventive interventions. For example, the Dutch 1998 cholesterol guidelines advise to reimburse cholesterol-lowering therapy up to approximately 20,000‰ per QALY [60,61]. The cost-effectiveness of smoking cessation is roughly within the same range as the cost-effectiveness of breast cancer screening in The Netherlands (4000‰ per life-year gained) and the cost-effectiveness of the Dutch influenza vaccination program for the elderly (1800‰ per life-year gained) .