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Cout efficacite des strategies de depistage du cancer du col uterin en Tunisie [Cost effectiveness of cervical cancer screening strategies in Tunisia] |
Hsairi M, Fakhfakh R, Ghyoula M, Ben Abdallah M, Achour N |
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Record Status 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. Health technology Cervical cancer screening strategies using the Pap test were compared according to age group and test frequency.
Type of intervention Secondary prevention; Screening.
Economic study type Cost-effectiveness analysis.
Study population The study population comprised a hypothetical cohort of women based on projections of the Tunisian population from the National Institute of Statistics.
Setting The practice setting was institution. The economic study was carried out in Tunis (Salah Azaiez Institute and Tunisian Public Health Institute).
Dates to which data relate The effectiveness analysis was based on data collected in 2000 from the Tunisian Institute of Statistics, and studies published between 1984 and 1994. 1995 prices were used.
Source of effectiveness data Estimates for the relative risk of cervical cancer screening were derived from a review. Estimates for the effectiveness of the screening programme were based on estimates made by the authors.
Outcomes assessed in the review The outcome assessed was the relative risk for developing cervical cancer according to the frequency of the Pap test screening.
Study designs and other criteria for inclusion in the review Sources searched to identify primary studies Criteria used to ensure the validity of primary studies Methods used to judge relevance and validity, and for extracting data Number of primary studies included Two primary studies were included.
Methods of combining primary studies The narrative method was used to combine the results of the individual primary studies.
Investigation of differences between primary studies Results of the review The relative risk of developing cervical cancer was 0.18 for a screening test every 3 years, and 0.37 for a screen every 5 years. No confidence intervals were reported.
Measure of benefits used in the economic analysis The number of cervical cancers avoided, as reported earlier, was expressed as benefits (percentage of avoided cases x number of incident cases). The authors used a formula to calculate the effectiveness of screening strategies based on a follow-up period of 10 years. The formula associated the coverage level of screening, the relative risk and the incident cases of cervical cancer according to age group and frequency of the screening, although interpretation of this formula would be problematic for the reader as it is not clearly described. Data relating to the number of women affected by the screening programme were not reported.
Direct costs Direct costs included only the Pap test cost (11.2 Dinars). 1995 prices were used. No discount rate was applied although the study covered a period of 10 years. Costs and quantities were analysed separately. The authors did not report marginal costs. They reported only average costs. The price year was 1995.
Statistical analysis of costs No statistical analysis of costs was reported.
Indirect Costs No indirect costs were reported.
Currency Tunisian dinar (Tnd) and US dollars ($).
Sensitivity analysis No sensitivity analysis was reported.
Estimated benefits used in the economic analysis Over a follow-up period of ten years, the number of cervical cancers avoided was estimated to be 20 for 40-64 year old women tested every 5 years, if the screening coverage was 20%.
For 20-64 year old women tested every 3 years, the benefit in terms of cervical cancers avoided was estimated to be 34.
If the screening coverage were 90%, the benefit for the same age group was estimated to be 174.
Cost results The authors reported only the total annual costs for the more expensive screening strategy. This strategy was not clearly defined, but it is likely that this strategy concerned the 20-64 age group, screened every 3 years, with a screening coverage of 90%. The total annual cost of the more expensive strategy was Tnd 6,382,000. If the comparator was no screening this figure would represent the marginal cost of the programme.
Synthesis of costs and benefits No synthesis of costs and benefits, such as an incremental analysis, was performed. Only average costs per case avoided were calculated.
According to average findings, the cost per cervical cancer avoided was estimated to be "about" Tnd 41,000 in the population of 20-64 years old women screened every 3 years. This cost was estimated to be "about" Tnd 19,000 in the population of 40-64 years old women screened every 5 years.
Authors' conclusions To screen the 40-64 year old age group every 5 years was the most cost-effective strategy. However, the cost-effectiveness ratio for the screening strategy for the 35-64 years age group was also still in an acceptable range.
CRD COMMENTARY - Selection of comparators The comparator was not clearly stated but is likely to have been the absence of a screening and treatment programme to prevent cervical cancer. No justification for the choice of the comparator was given.
Validity of estimate of measure of effectiveness The authors did not state that a systematic review of the literature had been undertaken. The extent to which all relevant studies have been systematically included was not clear. More pertinent synthesis of the literature, with recent data, would have increased the validity of the results. The authors used data from two published studies. The authors did not consider the impact of differences between the primary studies when estimating effectiveness. The authors derived a measure of health benefit: the number of cervical cancers avoided by screening strategies. The instrument used to derive a measure of health benefit, a statistical model (projection and formula), was not clearly described.
Validity of estimate of measure of benefit The authors derived a measure of health benefit: the number of cervical cancers avoided by screening strategies. The instrument used to derive a measure of health benefit was a statistical model (projection and formula), but this was not well described. The methodology lacked some details, in particular the cohort size actually used was not defined. Ideally, life years saved should have been assessed for each screening strategy.
Validity of estimate of costs The cost perspective adopted was not stated. Ideally, the authors would have chosen a societal perspective. Even if the authors estimated costs from the Tunisian health care system, all categories of cost relevant to this perspective were not included in the analysis. In fact, only the cost of the Pap test was included. For example, the analysis did not include the cost of consultations or the cost of interventions and care for women who screened positive, although they may substantially increase the total cost of the cervical cancer screening programme. Therefore, the cost-effectiveness of the screening strategies may have been overestimated. Costs and quantities were not reported separately in all cases. Total costs were not reported for all screening strategies. Prices were taken from published national data. A sensitivity analysis of prices was not conducted. Although costs were incurred over a ten year' period, discounting was not undertaken. 1995 prices were used.
Other issues The authors made appropriate comparisons of their findings with those from other studies but did not address the issue of generalisability to other settings. The study examined the age group size and the frequency of the screening of cervical cancer and this was reflected in the authors' conclusions. The synthesis of costs and benefits could have been more informatively presented using a cost-benefit analysis that evaluated both costs and benefits (benefits valued in terms of cervical cancer treatment costs avoided). The authors did not report any further limitations of their study. Due to the above-mentioned caveats the results of the study need to be treated with some caution.
Some typographical errors were noted in the article such as the fact that the age group reported in the cost-effectiveness results was given as "35-64 years" and not "40-64 years" as reported in table 3.
Implications of the study A prospective study, evaluating the feasibility of a screening programme, should be undertaken before implementing cervical cancer screening.
Bibliographic details Hsairi M, Fakhfakh R, Ghyoula M, Ben Abdallah M, Achour N. Cout efficacite des strategies de depistage du cancer du col uterin en Tunisie. [Cost effectiveness of cervical cancer screening strategies in Tunisia] Tunisie Medicale 2000; 78(10): 557-561 Indexing Status Subject indexing assigned by NLM MeSH Age Distribution; Age Factors; Clinical Protocols; Cost-Benefit Analysis; Developing Countries; Female; Humans; Mass Screening /economics /methods; Patient Selection; Time Factors; Tunisia /epidemiology; Uterine Cervical Neoplasms /diagnosis /epidemiology /prevention & Vaginal Smears /economics; control AccessionNumber 22001006108 Date bibliographic record published 30/06/2002 Date abstract record published 30/06/2002 |
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