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.

A 4-year, multi-faceted, community-based research project to help women quit smoking was examined. The programme, Breathe Easy, involved the delivery of cessation services through support systems, health professionals, educators, worksites and the media. The programme and its evaluation were supported by a research grant from the National Institutes of Health.

Primary prevention.

Cost-effectiveness analysis.

The study population comprised women aged 18 to 64 years of different smoking categories. The categories were never smokers, former smokers (> 5 years and =/> 5 years), light smokers (fewer than 25 cigarettes/day) and heavy smokers (at least 25 cigarettes/day).

The setting was the community. The economic study was carried out in the USA.

The effectiveness and resource use data were derived from studies published between 1988 and 2000. The price year was 2002.

The effectiveness evidence was derived from a synthesis of completed studies.

A Monte Carlo life table model was constructed, using 10,000 cycles to determine the life expectancy for both the intervention and the comparison populations. Published life tables for white female never, former, light and heavy smokers were used to calculate the life expectancy for each smoking category in 5-year age strata. As the life table model ran, each age cohort with its smoking-related categories was cycled to the next higher age stratum and then experienced the appropriate mortality rates of that stratum. This cyclical process continued upwards through each of the age strata in the life tables.

The outcomes assessed from the literature were:

the efficacy of the intervention (change in smoking behavioural results after 4 years of implementation of the programme);

the populations of women included in the intervention and control groups; and

life expectancy (which was not related to smoking habits for the age group 18 to 24 years, owing to a lack of data).

It appears that a systematic review of the literature has not been undertaken to identify sources of data. Most of the evidence (basically, all data for the intervention) was derived from the Breath Easy study (quasi-experimental matched control design). Survival data were derived from the 1986 life tables.

Not stated.

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Three primary sources were used to derive the model inputs.

The primary estimates were not combined since each source provided a series of data used in the model.

Not stated.

Limited results of the Breathe Easy study were reported. In particular, after 4 years of implementation of the programme, compared with no intervention, the odds of being a smoker were 0.88 (95% confidence interval, CI: 0.78 - 1.00; p=0.02).

A total of 35,243 women were included in the intervention group and in the control group. Other data used in the model were not reported.

The summary benefit measure was the expected life expectancy. This was derived from the decision model. Discounting was applied and an annual rate of 3% was used.

Discounting was not relevant since the costs were incurred during a short timeframe. The unit costs were not presented separately from the quantities of resources used. The health services included in the economic evaluation were the development and implementation of the intervention, evaluation of the intervention, and research-related projects (including grant administration, heating, lighting and security). The costs associated with the development, implementation and evaluation of the intervention (which were named "direct costs") included personnel salaries, fringe benefits, consultant costs and operating costs. The cost/resource boundary of the granting agency was adopted. Resource use was estimated mainly using data derived from the Breath Easy clinical trial. The costs came from actual expenditures of grant monies for project services. The costs were adjusted to 2002 values using the Consumer Price Index.

The costs appear to have been treated deterministically.

The indirect costs were not included in the economic evaluation.

US dollars ($).

A sensitivity analysis was performed to examine the robustness of the estimated cost-effectiveness ratios to variations in some model inputs. In particular, because mortality data for the 18- to 24-year-old cohort were not available, two alternative estimates were used. One estimate provided a more favourable mortality experience for this age cohort than the base-case, while the other estimate provided a less favourable experience. Further, different discount rates of 0 and 5% were considered. Cost recovery rates (10 and 25%) and community volunteer opportunity costs ($10/hour and $25/hour) were also considered.

The estimated life-years saved with the community-based programme, compared with no intervention, were:

3,870 (90% CI: -2,100 - 9,857; p=0.15) with no discounting,

1,705 (90% CI: -65 - 3,475; p=0.06) with discounting at 3%, and

1,026 (90% CI: 126 - 1,926; p=0.04) with discounting at 5%.

The estimated total costs were not reported.

When only the costs of the intervention were considered, the incremental costs per life-year saved with the programme over no intervention were:

$509 (90% CI: 200 to infinity) with no discounting,

$1,156 (90% CI: 567 to infinity) with discounting at 3%, and

$1,922 (90% CI: $1,024 to $15,647) with discounting at 5%.

When direct costs were considered, the incremental costs per life-year saved with the programme over no intervention were:

$1,184 (90% CI: 465 to infinity) with no discounting,

$2,688 (90% CI: 1,320 to infinity) with discounting at 3%, and

$4,467 (90% CI: 2,380 - 36,376) discounting at 5%.

When the total grant costs were considered, the incremental costs per life-year saved with the programme over no intervention were:

$1,772 (90% CI: 696 to infinity) with no discounting,

$4,022 (90% CI: 1,973 to infinity) with discounting at 3%, and

$6,683 (90% CI: 3,555 - 54,422) with discounting at 5%.

The sensitivity analysis showed that changes in the assumptions for the young age group had only modest effects on the base-case results. The inclusion of other categories of costs increased the cost-effectiveness ratios.

The cost-effectiveness of the 4-year, multi-faceted, community-based research project to help women quit smoking was economically attractive from the perspective of a granting agency, and it compared favourable with other smoking cessation therapies. The results of the analysis depended on the choice of the discount rate.

No details of the comparator used in the analysis were provided. It would appear that the comparator was no intervention, although it was not clearly stated. Likewise, there was limited information on the intervention examined in the study (i.e. the community-based research project). You should decide whether they are valid comparators in your own setting.

The effectiveness evidence came mainly from a published quasi-experimental study, which was carried out in two counties in the USA. Few details of the study design were provided, but the authors noted some limitations to the validity of the evidence. Other data were derived from life tables and all estimates were entered into the decision model. The data were not combined since each study provided a series of estimates. The most uncertain estimate, mortality data in the younger age group, was varied in the sensitivity analysis.

The use of survival as the summary benefit measure was appropriate, not only because it represented the most relevant dimension of health affected by the programme, but also because it is comparable with the benefits of other health care interventions. Discounting was applied and different rates were used. Moreover, undiscounted results were also reported. A probabilistic approach was used to examine the expected survival.

A restricted perspective was adopted in the study and only those costs related to the granting agency were considered. Accordingly, the costs came from grant expenses. Details of the unit costs and quantities of resources used were not provided, which limits the possibility of replicating the study in other settings. The costs were incurred during a short timeframe and no discounting was applied. The inclusion of alternative categories of costs was examined in the sensitivity analysis. The costs were treated deterministically and the total costs were not reported. The price year was reported, which aids reflation exercises in other settings.

The authors noted the difficulty in making comparisons with other studies because of a lack of clinical and economic evidence focusing on interventions targeting only women. However, the results of other studies were extensively reported and an exhaustive discussion of the possible differences across studies was undertaken. The issue of the generalisability of the study results to other settings was partially addressed. The authors stated that if the Breath Easy programme was implemented in other communities, the benefits of the investment in the research aspects of the project (i.e. its evaluation) would extend beyond those achieved during the project. However, only limited sensitivity analyses were performed. The authors noted not only some limitations of their study, which have been reported already, but also some strengths. For example, the use of validated data on survival and robust data on the effect of the smoking cessation programme.

The study results supported the implementation of the 4-year, multi-faceted, community-based research project to help women quit smoking. The authors suggested that, for non-profit agencies interested solely in funding a similar community-based smoking reduction intervention, without the evaluation costs associated with a research project, such an investment would be highly cost-effective.

Supported by grants from the National Institutes of Health.

Fiscella K, Franks P. Cost-effectiveness of the transdermal patch as an adjunct to physicians' smoking cessation counseling. JAMA 1996;275:1247-51.

Cromwell J, Bartosch WJ, Fiore MC, et al. Cost-effectiveness of the clinical practice recommendations in the AHCPR guideline for smoking cessation. JAMA 1997;278:1759-66.