Economic evaluation of specific immunotherapy versus symptomatic treatment of allergic rhinitis in Germany Schadlich P K, Brecht J G

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1 Economic evaluation of specific immunotherapy versus symptomatic treatment of allergic rhinitis in Germany Schadlich P K, Brecht J 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 Use of specific immunotherapy (SIT) (hyposensitisation) for a period of three years in patients with seasonal (pollen) or perennial (mite) allergic rhinitis. Type of intervention Treatment. Economic study type Cost-effectiveness analysis. Study population Patients with seasonal (pollen) or perennial (mite) allergic rhinitis. Setting Hospital. The economic study was carried out in Germany. Dates to which data relate Clinical probabilities were obtained from literature published between 1974 and The dates for resource use data, estimated from a survey of specialists or expert interviews, were not specified. Cost data related to 1990, 1992, 1995, and No unique price year was specified for the study. Source of effectiveness data Effectiveness data were derived from a review of the literature. Modelling A decision tree model was constructed to represent the natural progression of the disease and to estimate expected costs and effects associated with each strategy over a period of 10 years. Outcomes assessed in the review The review assessed the following outcomes: prevalence of asthma in the study population at the start of treatment, the cumulative incidence of asthma, the cumulative remission of asthma symptoms, the excess mortality of patients with asthma, the remission rate per year (the reduction in the need for anti-allergic pharmacotherapy), and the frequency of adverse events requiring treatment (only for SIT). Page: 1 / 5

2 Study designs and other criteria for inclusion in the review Clinical trials and observational studies conducted in Germany were used to estimate the prevalence of asthma in the study population at the start of treatment. Studies conducted in Germany or countries similar to Germany with respect to allergen exposure (i.e. Scandinavia, Switzerland, the UK, and the USA) were used to derive the cumulative incidence and remission of asthmatic symptoms. No further information was given. 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 A total of 43 studies were included. Methods of combining primary studies Average values of the clinical parameters were reported to have been used (upper and lower limits were used in the sensitivity analysis). Investigation of differences between primary studies Results of the review The probabilities used in the model were as follows: average prevalence of asthma in the study population at the start of treatment, 30% (lower limit/upper limit: 9% - 44%); the cumulative incidence of asthma per year, 0.74% ( ) with SIT and 2.52 ( ) with symptomatic treatment; the cumulative remission of asthma symptoms per year, 6.4% ( ) with SIT and 2.45% with symptomatic treatment; the excess mortality of patients with asthma, 0.48% ( ), 0.22% with symptomatic treatment and 0.16% with SIT; remission rate per year (the reduction in the need for anti-allergic pharmacotherapy), 1.93% (1.26% - 4%); and the frequency of adverse events requiring treatment (only for 3-year administration of SIT), ( ) per patient-year during SIT with allergoids and ( ) per patient-year during SIT using depot extracts in mite allergy. Measure of benefits used in the economic analysis The benefit measure was the number of additional patients free from asthma symptoms after 10 years. Page: 2 / 5

3 Direct costs Costs were discounted. Quantities were reported separately from the costs and cost items were reported separately. The cost analysis covered the patient-related (outpatient and inpatient) direct medical costs of SIT over the 3-year treatment period, incorporating the acquisition cost for allergen extracts, diagnostic measures, medical services during administration of SIT and treatment of adverse events; and anti-allergic treatment and treatment of asthma in the case of symptomatic pharmacotherapy. The perspective adopted in the cost analysis was that of the statutory health insurance (SHI) provider, the healthcare system, and society in Germany. The sources of resource use data were a survey of specialists and expert interviews. The sources of cost data were studies and reports (including cost-of-illness studies) published between 1993 and Cost data were taken from 1990, 1992, 1995, and The average costs/expenses (depending on the perspective adopted) were used in the base-case cost analysis. There was no unique price year for the study. The cost analysis did not cover direct non-medical costs such as patients' expenses for transportation, tissues, high efficiency particulate air filter vacuums and carpet removal. Indirect Costs Costs were discounted. Quantities were not reported separately from the costs. Cost items were not reported separately. Indirect cost analysis covered the costs of productivity loss caused by absence from work, premature retirement, and premature death. The perspective adopted in the cost analysis was that of society in Germany. The sources of cost data were studies published between 1993 and The price date (for example for hourly wages) was not explicitly reported. Currency German marks (DM). The exchange rate was DM1 = $ in 1997 values. Sensitivity analysis The robustness of the results was evaluated by performing best-case/worst-case scenario analyses, threshold analysis in terms of identifying the break-even point for costs (based on equal effectiveness of the alternative modalities), and impact analysis (one-way sensitivity analysis). Estimated benefits used in the economic analysis The number of patients free from asthma symptoms after 10 years was estimated to be 161 (from a cohort of 1000 patients) based on the change in the proportion of patients with asthma from 30% at the start of treatment to 19% after 10 years for SIT patients versus a change from 30% to 35% for the patients assigned to symptomatic treatment. Cost results The discount rate was 5%. The administration of SIT in pollen allergy using allergoids was associated with a cost saving of DM1,190 from the societal perspective, DM670 from the perspective of the healthcare system, and DM650 from the perspective of the SHI. The corresponding savings for the administration of SIT in mite allergy using depot extracts were DM1,100, DM580, and DM590. Synthesis of costs and benefits Notwithstanding the fact that the administration of SIT was the dominant strategy (with both better effectiveness and economic outcomes), the authors calculated the incremental cost per additional patient free from asthma symptoms as the measure of cost-effectiveness. This resulted in net savings per asthma- symptom-free patient of DM7,410 (societal), DM4,180 (healthcare system), and DM4,070 (SHI) for the administration of SIT in pollen allergy using allergoids. The corresponding savings for the administration of SIT in mite allergy using depot extracts were DM6,850, DM3,640, and DM3,640. The threshold analysis demonstrated that the break-even cost points from each perspective were reached in year 6 (societal) and year 7 (healthcare system and SHI) for the administration of SIT in pollen allergy using allergoids, and year 7 (societal), or year 8 (healthcare system or SHI) for the administration of SIT in mite allergy using depot extracts. Page: 3 / 5

4 Authors' conclusions This evaluation showed that SIT for 3 years is economically advantageous in patients who are allergic to pollen or mites and whose symptoms are inadequately controlled by continuous symptomatic treatment. After 10 years, the administration of SIT leads to net savings from the perspectives of society, the healthcare system and SHI (third-party payer) in Germany. CRD COMMENTARY - Selection of comparators No specific justification was provided for the choice of the comparator although it was mentioned to be one of 3 alternative treatment approaches suitable in the given context. You, as a database user, should consider whether this a widely used health technology in your own setting. Validity of estimate of measure of benefit The internal validity of the estimate of benefit cannot be objectively assessed due to the limited reporting of the literature review, and of how quality assessment of the primary studies included in the review was achieved. Validity of estimate of costs Some quantities were reported separately from the costs and adequate details of the methods of cost estimation were given. Cost results may not be generalisable to other settings since the authors restricted their cost analysis to Germany. As the authors noted, the cost analysis did not cover the non-medical direct costs, which were deemed not to affect the cost results in any radical way. The study lacked a unique price year. Other issues The authors' conclusion seems to be justified given the extensive sensitivity analyses performed. The issue of generalisability to other settings or countries was not addressed since the authors restricted their analysis to Germany. However, appropriate comparisons were made with other studies. Implications of the study SIT is a well tolerated form of therapy and will result in net savings for SHI, the healthcare system, and society in Germany as long as patients who are eligible for SIT are properly selected and treated according to current recommendations. SIT is a well tolerated and cost-saving therapy if given to the appropriate patient. Source of funding Funded by Allergopharma Joachim Ganzer KG (Reinbek), Bencard Allergie GmbH (Munchen), and HAL ALLERGIE GmbH (Dusseldorf). Bibliographic details Schadlich P K, Brecht J G. Economic evaluation of specific immunotherapy versus symptomatic treatment of allergic rhinitis in Germany. PharmacoEconomics 2000; 17(1): PubMedID Indexing Status Subject indexing assigned by NLM MeSH Delivery of Health Care /economics; Economics, Pharmaceutical; Follow-Up Studies; Germany /epidemiology; Page: 4 / 5

5 Powered by TCPDF ( Humans; Immunotherapy /economics; Insurance, Health; Mite Infestations /therapy; Pollen; Prevalence; Rhinitis, Allergic, Perennial /economics /epidemiology /therapy AccessionNumber Date bibliographic record published 31/12/2000 Date abstract record published 31/12/2000 Page: 5 / 5