Alternative management strategies for patients with suspected peptic ulcer disease Fendrick M A, Chernew M E, Hirth R A, Bloom B S

Transcription

1 Alternative management strategies for patients with suspected peptic ulcer disease Fendrick M A, Chernew M E, Hirth R A, Bloom B S 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 The diagnosis and treatment of suspected peptic ulcer using alternative invasive and noninvasive strategies. In particular 1) immediate endoscopy for diagnosing peptic ulcer and biopsy for diagnosing Helicobacter pylori, followed by antisecretory therapy for ulcer treatment and antibiotic therapy for H.pylori treatment; 2) immediate endoscopy without biopsy, followed by antisecretory and antibiotic therapy for all diagnosed with peptic ulcer; 3) no initial diagnostic testing, qualitative serologic test for H.pylori, followed by antisecretory therapy and, if test positive, antibiotic therapy; 4) no initial diagnostictesting, all patients prescribed antisecretory therapy alone and 5) no initial diagnostic testing, all patients prescribed both antisecretory and antibiotic therapy. Type of intervention Diagnosis; Treatment. Economic study type Cost-effectiveness analysis. Study population A hypothetical cohort of patients with suspected peptic ulcer disease. Setting The practice setting was hypothetical but was assumed to be primary and secondary (hospital) care. Dates to which data relate Effectiveness data related to studies completed between 1974 and The price year was not stated and resource data were not given. Source of effectiveness data Effectiveness data was taken from a review of previously completed studies. Modelling A decision analytic model was used to predict the natural history of peptic ulcer disease, its interaction with H.pylori infection, and the effects of the various diagnostic and therapeutic interventions. Outcomes assessed in the review The primary clinical outcomes assessed were: probabilities relating to the incidence of active ulcer disease, rates of ulcer healing, H.pylori infection, recurrence of symptoms and the sensitivity and specificity of serologic tests for H.pylori. Page: 1 / 5

2 Study designs and other criteria for inclusion in the review Study designs were not specified. The authors did not state whether any criteria were used for inclusion in review. Sources searched to identify primary studies Primary studies were identified by a MEDLINE search. Additional searches were made of current issues of general medicine, infectious disease and gastroenterology journals not identified by the MEDLINE search. Unpublished data were obtained from data presented at the 1994 NIH Consensus Development Meeting. Criteria used to ensure the validity of primary studies Not stated. Methods used to judge relevance and validity, and for extracting data The methods used to judge the relevance and validity were not specified. Data were extracted from the studies to give both a base case and range of probabilities for the clinical model but the method was not specified. Number of primary studies included Approximately forty six studies were included. Methods of combining primary studies Not stated. Investigation of differences between primary studies The authors did not investigate any differences found between the primary studies. When confronted with uncertainty in the estimation of clinical probabilities, base case probabilities were based on assumptions that favoured the initially invasive diagnostic strategies. Results of the review The findings from the review were combined to provide the clinical input probabilities and ranges used in the simulation model. Particularly pertinent among these findings were: 1) active ulcer disease (20% range 5-30%), 2) H.pylori was seen more frequently when an ulcer caused the symptoms (95% range 75-95%) than when it did not (50% range 20-60%), 3) recurrent symptom rate was higher with active ulcers (90% range 50-90) compared with healed ulcers (10% range 0-30%), 4) ulcer recurrence rate was higher with H.pylori infection (2.7%/100 patient-months, range 2-6.6) than with no infection (0.6%/100 patient-months, range ), 5) ulcer healing rate after antisecretory therapy (75% range 50-90%), 6) H.pylori eradication after antibiotic course (includes compliance) (80% range 50-90%) and 7) sensitivity of serologic test (95% range %) and specificity (95% range %). Page: 2 / 5

3 Measure of benefits used in the economic analysis The measure of benefits were ulcer cure rates. Direct costs A decision tree analysis was used to model the usage of resources. Direct health service costs were based on actual payments for ambulatory services, inpatient care and physician by a private third-party payer. Direct costs of pharmaceutical agents were estimated by actual payments made by patients at seven retail pharmacies in three eastern states. Costs and quantities were not reported separately. The price date for costs was not stated and costs were not discounted although this was not necessary given that the one year duration of the study. Statistical analysis of costs No statistical analysis of costs was undertaken. Indirect Costs The indirect costs of the alternative strategies were not considered. Currency US dollars ($). Sensitivity analysis A sensitivity analysis of costs and benefits (clinical probability estimates) was carried out. The areas of uncertainty examined were variability in data and generalisability of results. Both one-way simple and multi-way simple sensitivity analyses were undertaken with a threshold analysis and an analysis of extremes ("worst case" scenario only). The values were those which would enhance the cost-effectiveness of the immediate endoscopy strategies or diminish the costeffectiveness of initial noninvasive strategies. Estimated benefits used in the economic analysis The benefits used in the economic analysis were reported in terms of the rates of ulcers cured by the end of the study period. However, since nearly all active ulcers and associated H.pylori infections were objectively diagnosed and treated by the end of the study period in each strategy, the percentage of patients who had a persistent active ulcer in each strategy was low (1%-2% of the entry population) at the end of the study year. The duration of the benefit from the intervention was based on the 1 year study duration. Side effects were not considered. Cost results The total costs of each strategy were not presented. The costs were expressed as an average cost per patient treated. Assuming that equal numbers of patients received each strategy, total intervention costs can be estimated from the costs presented as follows: 1) Strategy 1 - $316,800 (average cost = $1,584); 2) strategy 2 - $275,000 (average cost = $1,375); 3) strategy 3 - $178,800 (average cost = $894); 4) strategy 4 - $190,400 (average cost = $952) and 5) strategy 5 - $163,600 (average cost = $818). Page: 3 / 5

4 The duration of costs and quantities for all strategies was 1 year. Synthesis of costs and benefits The estimated benefits and costs were combined using average cost per ulcer cured. No incremental analysis was performed since each strategy was assumed to be equally effective at the conclusion of follow up. The results were reported in terms of the average cost per ulcer cured. The estimated treatment costs per ulcer cured by each strategy were as follows: endoscopy and biopsy for H.pylori (strategy 1), $8,045; endoscopy only (strategy 2), $6,984; serologic test for H.pylori (strategy 3), $4,541; empiric antisecretory therapy (strategy 4), $4,835 and empiric antisecretory and antibiotic therapy (strategy 5), $4,155. The duration of the benefit from the intervention was based on the 1 year follow-up. Side effects were not considered. The authors found that the cost-effectiveness advantage of the noninvasive strategies (3-5) relative to the immediate endoscopy strategies (1 and 2) was sensitive to two variables: 1) the cost of endoscopy (endoscopy costs must decrease to less than $500 for an equivalent cost-effectiveness ratio to result) and 2) the probability of recurrent symptoms in patients not initially treated with an invasive procedure and in whom ulcer disease was not the underlying cause of symptoms (as the annual recurrent symptom rate approached 80%, the cost per patient treated of the invasive strategies approached that of the immediate invasive diagnostic strategies). The cost-effectiveness advantage of the combined empiric regimen (strategy 5) compared with a strategy of initial serologic testing (strategy 3) was sensitive to the cost of the serologic test for H.pylori (if the cost of the test were to decrease to $12, an equivalent cost-effectiveness ratio would result). Authors' conclusions Cost-effectiveness analysis supports the continued use of noninvasive treatment strategies at the first symptomatic episode, adapted to address the possibility of H.pylori infection. The cost-effectiveness advantage of initial noninvasive strategies reflect the high cost of endoscopy compared with the cost of a course of antibiotic therapy. However the costeffectiveness advantage of initial noninvasive therapy was sensitive to the cost of endoscopy. If market forces lower the cost of endoscopy or, if the likelihood of endoscopy increases significantly in patients receiving empiric treatment, the most cost-effective strategy may alter to one of immediate diagnostic testing. CRD Commentary This is an important paper which addresses the question ofwhether invasive diagnostic procedures should be used at the first symptomatic episode of suspected peptic ulcer disease in a comprehensive manner. There are, however, a number of areas which the authors fail to address in adequate depth. In particular, no evidence is presented to support the validity and relevance of the primary studies used to determine the clinical probabilities used in the decision analysis and the method of combining the results of the studies is not clear. This makes it difficult to judge the validity of the decision model used by the authors. In addition since the authors base their estimates of costs on third party insurance payments (which will include profit and hence do not reflect the opportunity cost of resource usage), it is difficult to generalise the results to the UK. However, the authors have performed a comprehensive sensitivity analysis which gives credence to their conclusions that it appears cost-effective to use noninvasive management strategies at the first symptomatic episode. Source of funding None stated. Page: 4 / 5

5 Powered by TCPDF ( Bibliographic details Fendrick M A, Chernew M E, Hirth R A, Bloom B S. Alternative management strategies for patients with suspected peptic ulcer disease. Annals of Internal Medicine 1995; 123(4): PubMedID Original Paper URL Other publications of related interest Comment in: ACP Journal Club 1996;124(1):24 Indexing Status Subject indexing assigned by NLM MeSH Anti-Bacterial Agents /therapeutic use; Anti-Ulcer Agents /therapeutic use; Biopsy /economics; Cost-Benefit Analysis; Decision Support Techniques; Drug Therapy, Combination; Endoscopy, Gastrointestinal /economics; Helicobacter Infections /drug therapy; Helicobacter pylori; Humans; Peptic Ulcer /drug therapy /microbiology; Recurrence AccessionNumber Date bibliographic record published 30/09/1998 Date abstract record published 30/09/1998 Page: 5 / 5