Cost-effectiveness analysis of different strategies for treating duodenal ulcer Badia X, Segu J L, Olle A, Brosa M, Mones J, Ponte L G

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1 Cost-effectiveness analysis of different strategies for treating duodenal ulcer Badia X, Segu J L, Olle A, Brosa M, Mones J, Ponte L G 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 Eradication therapies for patients with H. pylori-positive duodenal ulcer (DU). Type of intervention Treatment. Economic study type Cost-effectiveness analysis. Study population Patients aged over 18 years, with H. pylori-positive duodenal ulcer. Setting Hospital. The economic study was carried out in Barcelona, Spain. Dates to which data relate The effectiveness data were obtained from studies published between 1987 and The cost values associated with the resources used in each of the stages included in the model were mainly obtained from studies published in 1992, 1993 and The price year was Source of effectiveness data Effectiveness data were derived from a review of previously completed studies and assumptions made by the authors. Modelling A Markov Chains model was used in order to estimate the costs and benefits associated with each treatment strategy. The model incorporated six health states: (1)Helicobacter pylori-positive symptomatic DU (starting point); (2) H. pylori-negative asymptomatic DU; (3) H. pylori-positive asymptomatic DU; (4) H. pylori-positive symptomatic uncomplicated DU; (5) H. pylori-positive symptomatic complicated DU; (6) Maintenance therapy with ranitidine. Page: 1 / 5

2 A Monte Carlo simulation was used to perform the model calculations. Each patient began at state 1 and was followed through the model for 10 years. The model used transition probabilities obtained from the literature review and using the formula p = 1- e?-rt. Outcomes assessed in the review The eradication rate associated with each strategy, and the transition probabilities between health states, as well as the non-compliance rates for each strategy and the days with symptoms were the outcomes assessed in the review. Study designs and other criteria for inclusion in the review Randomised controlled studies, observational studies and meta-analyses were included in the review. Sources searched to identify primary studies A search of Medline ( ) and abstracts presented in gastroenterology congresses ( ) were the reported as the sources searched. Criteria used to ensure the validity of primary studies The criteria were reported as follows: (a) one of the therapies compared had to be triple therapy with omeprazole plus clarithromycin plus amoxicillin, administered to patients over 18 years of age, with duodenal ulcer and not previously treated with non-steroidal antiinflammatory drugs (NSAIDs); (b) eradication was one of the outcome variables analysed. Only randomised controlled trials were retrieved. Methods used to judge relevance and validity, and for extracting data Two of the authors reviewed the quality of trials retrieved from the search, according to "previously established guidelines for the extraction of information". Number of primary studies included Thirteen studies were included. Three of these were randomised controlled trials, two were meta-analyses and the remaining eight were observational studies. Methods of combining primary studies Not combined. Investigation of differences between primary studies Only one randomised controlled study was used to obtain the final estimation of efficacy associated with the eradication treatment options. Results of the review The eradication rate for the triple eradication therapy was 96% and 98% for the quadruple eradication therapy. The eradication rate for omeprazole monotherapy (antisecretory therapy) was 0 %. H. pylori positive relapse rate was 58%, reinfection rate was 3.5%, H. pylori-negative relapse rate was 2.3% and complicated relapse rate was 1.5%. The noncompliance rate for the triple eradication therapy was 6% and the non-compliance rate for the antisecretory therapy was Page: 2 / 5

3 0%. Days with symptoms was given as 2. Methods used to derive estimates of effectiveness Assumptions about effectiveness were also made by the authors. Estimates of effectiveness and key assumptions A set of 10 assumptions made by the authors to simplify the model. Measure of benefits used in the economic analysis The measure of benefits used in the economic analysis was the number of days free of symptoms (DFS) for each strategy. A Markov Chains model was used in calculating that measure, by using a Monte Carlo simulation and following each one of a hypothetical 5,000-patient cohort through the model for a 10-year period. Direct costs Costs were discounted. Quantities were reported separately from the costs. The costs measured were operating costs and costs of complications. The cost analysis was performed from the perspective of a third-party payer. The costs were based on data from studies published in 1992, 1993 and The price year was The cost estimation was obtained for a 10-year period. Indirect Costs Not included. Currency Spanish Pesetas (Pta). The currency conversion rate reported was US$1= Pta128 (October 1995). Sensitivity analysis The variables investigated in the sensitivity analysis were as follows: days with symptoms, eradication rate, yearly relapse rate for H.pylori positive patients, rate of complicated relapse, reinfection rate, cost of hospitalisation and discount rate. One-way simple sensitivity and best-worst case scenario analyses were performed. Estimated benefits used in the economic analysis For the given hypothetical 5,000 patient cohort, S1 resulted in a mean of 2, days free of symptoms (DFS), S2 produced 2, DFS per patient, S3 produced 2, DFS and the antisecretory therapy resulted in 2, DFS per patient. The health effects were discounted at a rate of 5%. Cost results Given a 5% discount rate, the mean costs per patient for each strategy were as follows: S1, Pta78,457; S2, Pta64,270; S3, Pta60289; antisecretory therapy, Pta111,829. Page: 3 / 5

4 Synthesis of costs and benefits The cost per day free of symptoms (DFS) was the measure used to express the synthesis of costs and benefits associated with each treatment strategy. The figures were reported in 1994 prices and the discount rate used for costs and benefits was 5%. For a 10-year duration of costs and benefits, the cost per DFS was Pta27.3 for S1, Pta22.3 for S2, and Pta21.0 for S3. The comparator resulted in Pta39.0 per DFS. The corresponding figures for undiscounted results were Pta22.4, Pta19.7, Pta17.9, and Pta38.2. The ranking of strategies was invariant to the values explored in the one-way simple sensitivity analysis. The best-worst case scenario resulted in the eradication strategies having a better cost per DFS than the comparator, except for S1 (the worst case scenario consisted of H. pylori eradication rate of 50%, relapse rate in H. pylori-positive patients of 50%, and reinfection rate of 10%). Authors' conclusions The authors advised the treatment of patients experiencing a first episode of H. pylori-positive duodenal ulcer, or a relapse, with a triple therapy. The results suggest that treating both the initial H. pylori-positive DU and relapses with triple therapy is more cost-effective than any sequential combination of antisecretory agent and antibacterials, due to the lower relapse rate and the high treatment tolerance associated with the former. CRD COMMENTARY - Selection of comparators The comparator was antisecretory therapy, which was reported to be a widely used treatment strategy for H. pyloripositive duodenal ulcer patients. The antisecretory strategy consisted of omeprazole 20 mg/day for 4 weeks for each symptomatic episode of duodenal ulcer. All patients with a complicated duodenal ulcer relapse underwent maintenance treatment with ranitidine 150 mg/day. Validity of estimate of measure of benefit The internal validity of the study results may be weak, given the assumptions used in the model and the lack of "scientific evidence" for epidemiological factors (reinfection rates, relapse rates beyond a 1-year time period, DU incidence in different sub-populations, diagnosis of H. pylori infection and the resource use for treating it) as reported by the authors. Validity of estimate of costs The resource quantities were reported separately from the prices. However insufficient details were given regarding the method of calculation of the resource use estimates for each state. No important cost items appear to have been omitted. Other issues The authors' conclusions rely mostly upon the sensitivity analysis, although more epidemiological evidence is required before a more reliable statement can be reached, regarding the cost-effectiveness of the strategies involved in this study. The generalisability of the results was thought to depend on how important NSAID-related ulcers are in relation to the incidence of DU, as well as on "an adequate diagnostic strategy" to rule out those cases. The importance of NSAIDrelated ulcers will depend, according to the authors, on the prescription practices of the corresponding agents in each country. The study finding that eradication therapy was more cost-effective than antisecretory therapy ("whichever eradication therapy is used") was reported as consistent with results from studies carried out in other countries. The results were not presented selectively. Source of funding Financial support from Abbott Laboratories SA. Bibliographic details Badia X, Segu J L, Olle A, Brosa M, Mones J, Ponte L G. Cost-effectiveness analysis of different strategies for treating Page: 4 / 5

5 Powered by TCPDF ( duodenal ulcer. PharmacoEconomics 1997; 11(4): PubMedID Indexing Status Subject indexing assigned by NLM MeSH Anti-Ulcer Agents /therapeutic use; Cost-Benefit Analysis; Duodenal Ulcer /drug therapy; Helicobacter pylori /drug effects; Humans; Markov Chains; Omeprazole /therapeutic use; Recurrence; Sensitivity and Specificity AccessionNumber Date bibliographic record published 31/12/1999 Date abstract record published 31/12/1999 Page: 5 / 5