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Cost-benefit analysis of interferon therapy in children with chronic active hepatitis B |
Louis-Jacques O, Olson A D |
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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 Alpha-Interferon therapy in children with chronic active hepatitis B.
Economic study type Cost-effectiveness analysis.
Study population The authors considered patients with a histologic diagnosis of CAH, no evidence of cirrhosis, with active viral replication, confirmed by a positive hepatitis B e antigen (HbeAg), positive Hepatitis B virus (HBV) DNA, and increased transaminases for 6 months or longer. The patients would also be positive for hepatitis B surface antigen but negative for anti-delta antibody.
Setting Hospital. The study was carried out at the University of Michigan Medical Centre, Ann Arbor, Michigan, USA.
Dates to which data relate Effectiveness data were derived from studies published between 1972 and 1995. Resource use data were derived from the authors' institution. Cost data were collected from studies published between 1993 and 1995. The price year was not reported.
Source of effectiveness data Effectiveness data were derived from a review of the literature.
Outcomes assessed in the review The review assessed the following outcomes: disease-free latency period, incidence of cirrhosis, lifetime risk of developing decompensated cirrhosis or hepatocellular carcinoma (HCC), the risk of death after decompensation, incidence of HCC, mortality from HCC, and the protection rate from IFN.
Study designs and other criteria for inclusion in the review Sources searched to identify primary studies A Medline search of English-language studies was made.
Criteria used to ensure the validity of primary studies Methods used to judge relevance and validity, and for extracting data Summary statistics from individual studies were used.
Number of primary studies included At least 27 primary studies were included in the review.
Methods of combining primary studies Investigation of differences between primary studies Results of the review The results of the review were as follows:
The disease-free latency period from initial presentation to onset of the first cases of cirrhosis was 10 years for adults and children.
The annual incidence of cirrhosis was 3% for adults and children.
The annual risk of decompensation of cirrhosis was 5% for adults and children.
17% of adults and children who have decompensated cirrhosis, and who do not get liver transplantation, would die each year.
The annual incidence of HCC among patients with cirrhosis was 2% among adults and 1% among children.
Annual mortality from HCC was 40% among adults.
The protection rate from IFN was varied between 6% and 30%.
Measure of benefits used in the economic analysis The number of life years saved was used as the measure of benefits. Life expectancy at birth was taken to be 75.5 years. Years of life saved were discounted at 5% per year.
Direct costs Direct costs were discounted at 5% per year. Quantities and costs were reported separately. Direct costs included the cost of evaluation, treatment with IFN, and follow-up. The quantity/cost boundary adopted was that of the hospital. The estimation of quantities and costs was based on actual data. Costs incurred by patients with cirrhosis and HCC were derived from published sources. The costs of liver transplantation, and follow-up and medication costs were obtained from the authors' institution. The price year was not reported.
Statistical analysis of costs Sensitivity analysis Sensitivity analyses were performed on the response rate to IFN, the costs per patient treated, and the latency period.
Estimated benefits used in the economic analysis Including liver transplantation, the use of IFN would lead to an average increase in life expectancy ranging from 0.2 years in adults to 0.5 years in children in the case of a 6% response, and from 1.1 years in adults to 2.6 years in children in the case of a 30% response.
Without transplant, a 6% response rate would result in an average increase in life expectancy of 0.1 years in adults to 0.2 years in children; a 30% response rate would lead to an increase of 0.5 years in adults to 1 year in children.
Cost results Including liver transplantation costs and with a 30% response rate, the use of IFN leads to savings in the children's group and to a small cost of $1,000 for adolescents and adults. Including liver transplantation costs and with a 6% response rate, the use of IFN is associated with a modest increase in expense in comparison to standard care of $2,900 for children and $5,000 for adolescents and adults. If liver transplantation costs are excluded, the results vary only by a small amount.
Synthesis of costs and benefits Including liver transplantation costs and with a 30% response rate, the cost per life year saved was -$425 in children, $510 in adolescents, and $934 in adults. Including liver transplantation costs and with a 6% response rate, the cost per life year saved was $5,650 in children, $12,887 in adolescents, and $22,088 in adults.
Excluding liver transplantation costs and with a 30% response rate, the cost per life year saved was -$215 in children, $2,389 in adolescents, and $3,071 in adults. Excluding liver transplantation costs and with a 6% response rate, the cost per life year saved was $16,017 in children, $33,525 in adolescents, and $51,232 in adults. These results were sensitive to the assumption that response to IFN by conversion of HbeAg prevents the onset of cirrhosis and HCC.
Authors' conclusions Interferon therapy for patients with chronic active hepatitis B is cost-effective. Interferon is more cost-effective in toddlers than adults because of the smaller dose required and the greater increase in life expectancy of children.
CRD COMMENTARY - Selection of comparators A justification was given for the comparator used, namely that it represented current practice. You, as a user of the database, should decide if this is a widely used health technology in your own setting.
Validity of estimate of measure of benefit The authors derived their estimates of effectiveness from a Medline search and therefore a high degree of validity can be anticipated for the results. Effectiveness estimates were combined credibly from primary studies using narrative methods. Estimation of benefits was obtained directly from the effectiveness analysis. This choice of estimate was justified.
Validity of estimate of costs All categories of costs relevant to the perspective adopted were included in the analysis. The costs of screening tests for HCC, however, were not considered. The authors did not include indirect costs such as those incurred for travelling for clinic appointments or loss of income secondary to hospitalisation. The inclusion of these costs would make treatment with IFN a more attractive option. Good aspects of the analysis of costs were that quantities were reported separately, a sensitivity analysis was conducted on costs, and no charges were used to proxy price. The price year, however, was not reported.
Other issues The authors did make appropriate comparisons of their findings with those from other studies, although the issue of generalisability to other settings was not addressed. The authors did not present their results selectively. The study analysed patients with active chronic hepatitis B and this was appropriately reflected in the authors' conclusions.
Implications of the study The availability of a treatment which, when given early, can limit the progression of chronic hepatitis B to cirrhosis and HCC, and the finding that this therapy is cost-effective, underscore the fact that early detection of chronic hepatitis caused by HBV may be critical. Formal evaluations of the cost-effectiveness of related screening programmes should also be considered.
Bibliographic details Louis-Jacques O, Olson A D. Cost-benefit analysis of interferon therapy in children with chronic active hepatitis B. Journal of Pediatric Gastroenterology and Nutrition 1997; 24(1): 25-32 Indexing Status Subject indexing assigned by NLM MeSH Adult; Child; Child, Preschool; Cohort Studies; Cost-Benefit Analysis; Drug Costs; Hepatitis B /therapy; Hepatitis, Chronic /therapy; Humans; Interferon-alpha /therapeutic use AccessionNumber 21997000522 Date bibliographic record published 30/09/2000 Date abstract record published 30/09/2000 |
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