The cost effectiveness of strategies for the treatment of intestinal parasites in immigrants Muennig P, Pallin D, Sell R L, Chan M

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1 The cost effectiveness of strategies for the treatment of intestinal parasites in immigrants Muennig P, Pallin D, Sell R L, Chan M 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 use of universal screening plus treatment of infected individuals only, or universal presumptive treatment (400 mg of albendazole per day for five days) in the management of intestinal parasites in immigrants at risk for parasitosis. Type of intervention Screening, primary prevention, and treatment. Economic study type Cost-effectiveness analysis and cost-utility analysis. Study population Immigrants (refugees or asylum seekers) at risk for parasitosis (from five regions: Eastern Europe, Latin America and the Caribbean, sub-saharan Africa, the Middle East, and Asia). Setting Primary care and hospital. The economic study was carried out in New York, NY, USA. Dates to which data relate Effectiveness data were extracted from reports or studies published between 1983 and Resource use data were related to the period between 1990 and The fiscal year was Source of effectiveness data Effectiveness data were derived from a review of the literature and assumptions made by the authors. Modelling A decision analytic model was employed to estimate the costs and effects associated with the three strategies considered in the study using DATA 3.0 software for the Macintosh computer. Outcomes assessed in the review The review assessed morbidity (as measured by the probability of an outpatient visit for Strong. stercoralis and the probability of admission for Strong. stercoralis infection), treatment efficacy (measured by the probability of albendazole eradicating Strong. stercoralis), and mortality (represented by the probability of dying from disseminated strongyloidiasis and the probability of dying from A. lumbricoides infection). Study designs and other criteria for inclusion in the review Page: 1 / 5

2 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 In total, 21 studies were used. Methods of combining primary studies Investigation of differences between primary studies Results of the review Morbidity (measured by the probability of an outpatient visit for Strong. stercoralis) was (range: ), and the probability of admission for Strong. stercoralis infection was (range: ). Treatment efficacy, measured by the probability of albendazole eradicating Strong. stercoralis, was 0.85 (range: ). Mortality, represented by the probability of dying from disseminated strongyloidiasis, was (range: ), and the probability of dying from A. lumbricoides infection was (range: ). Methods used to derive estimates of effectiveness Assumptions about effectiveness were also made by the authors. Estimates of effectiveness and key assumptions It was assumed that the probability of a post-treatment medical visit (side effects) was 0.01 (range: ); mortality rate because of infection with hookworm or Trichuris trichiura was zero; the efficacy of prescribed regimen (400 mg of albendazole per day for five days)in the treatment of Ascaris lumbricoides, hookworm, and Trich. trichiura infection was 100%; the efficacy of prescribed regimen in the treatment of Strong. stercoralis infection was 85%; the compliance of immigrants regarding the use of the prescribed regimen was similar to the patients having participated in the effectiveness trial of albendazole against strongyloidiasis. Measure of benefits used in the economic analysis Disability-adjusted life-years (DALYs) averted and hospitalization averted were the main benefit measures used in the economic study. The loss of one year of healthy life to disease was used to define one DALY. The calculation of DALYs averted was based on the methods and disability weights used in a study published in Direct costs Page: 2 / 5

3 Costs were discounted. Quantities of resource use as the rate of outpatient visit and hospitalization were reported separately from the costs. The cost items were reported separately. The cost analysis covered the costs of albendazole, inpatient care, outpatient visits including follow-ups due to side effects, and stool examination. The perspective adopted in the cost analysis was that of society. Regional databases related to the years between 1990 and 1996 were used to estimate the outpatient visit and hospitalization rates. Cost data were obtained from software, reports, and studies published between 1994 and Mean charges were used to estimate the costs of hospital stay price data were used. The consumer price index was used to convert the cost data to 1997 figures. The cost of Strong. stercoralis infection as a nonprimary diagnosis was not included in the cost analysis. Indirect Costs Costs were discounted. Quantities of resources used were not fully reported separately from the costs. Lost wages were estimated based on the average length of hospital stay for the treatment of each type of parasite. The data from the Office of Refugee Resettlement were used to estimate the cost of lost productivity for all immigrant groups price data were used. Currency US dollars ($). Sensitivity analysis Univariate and bivariate sensitivity analyses were used to test the robustness of the results to changes in all parameters of the model. Threshold analyses were performed for sensitive parameters of the model. Worst-case, best-case scenarios were investigated. Estimated benefits used in the economic analysis It was estimated that, in total, the use of presumptive treatment would result in 870 DALYs averted and 374 hospitalization averted compared to the strategy of no preventive intervention for the 1996 population of immigrants (n=698,522). The DALYs averted for the specific groups of immigrants were: Asia (n=282,632), 543; the Middle East (n=5,047), 1 ; Sub-Saharan Africa (n=51,537), 94; Latin America and the Caribbean (n=267,334), 191; Eastern Europe (n=91,972), 40. The total number of DALYs averted for the strategy of universal screening was 185. The corresponding DALYs averted for the groups of immigrants were 115, 0, 20, 41, and 9, respectively. A discount rate of 3% was applied to the DALYs. Cost results The discount rate was 3%. The total gross cost of the strategy of no preventive intervention was $11,086,181 for the 1996 population of immigrants (n=698,522). The cost per group of immigrants was: Asia (n=282,632), $6,330,957; Middle East (n=5,047), $40,073; Page: 3 / 5

4 Sub-Saharan Africa (n=51,537), $1,154,429; Latin America and the Caribbean (n=267,334), $2,649,280; Eastern Europe (n=91,972), $911,443 The total net cost of the strategy of presumptive treatment was $-4,244,679 (gross cost was $7,290,624). The corresponding values for the groups of immigrants were $-3,103,299, $6,561, $-565,876, $-548,035, and $-34,030, respectively. The strategy of universal screening had a total net cost of $29,461,470. The corresponding values for the groups of immigrants were $11,746,186, $216,668, $2,141,878, $11,425,855, and $3,930,883, respectively. Synthesis of costs and benefits Cost per DALY averted and cost per hospitalization averted were calculated as the measures of cost-effectiveness when compared with the strategy of no preventive intervention. The strategy of presumptive treatment had a cost per DALY averted of $4,630 and cost per hospitalization averted of $5,029, for the group of immigrants from the Middle East; the strategy was the dominant in total and for other groups of immigrants. The strategyof universal screening had a total cost per DALY averted of $159,236 and cost per hospitalization averted of $85,989. The respective cost per DALY averted for the groups of immigrants from Asia, the Middle East, Sub-Saharan Africa, Latin America and the Caribbean, and Eastern Europe were $101,801, $722,372, $106,706, $280,966, and $457,383, respectively. The sensitivity analyses revealed that the most sensitive parameters of the models were the prevalence of Strong. Stercoralis infection, the probability that treatment will be successful, the probability of side effects, the probability of hospitalization due to Strong. Stercoralis, and the cost of hospitalization. Authors' conclusions Presumptive administration of albendazole to all immigrants at risk for parasitosis would save lives and money. Universal screening, with treatment of persons with positive stool examinations, would save lives but is less cost effective than presumptive treatment. CRD COMMENTARY - Selection of comparators The reason for the choice of the comparator is clear. The approaches under investigation have been recommended by the governments of several countries. Validity of estimate of measure of benefit The internal validity of the estimates of the benefit measures cannot reasonably be guaranteed due to the apparent lack of a comprehensive literature review, and quality assessment of the primary studies and databases used to derive the clinical outcomes. Validity of estimate of costs Quantities of resources were not fully reported separately from the costs. However, adequate details of methods of cost estimation were given. Other issues The authors' conclusion is justified given the comprehensive sensitivity analyses performed to address uncertainties surrounding the parameters of the model. The issue of generalisability to other settings or countries was addressed and some comparisons were made with other studies in the literature. Source of funding None stated. Page: 4 / 5

5 Powered by TCPDF ( Bibliographic details Muennig P, Pallin D, Sell R L, Chan M. The cost effectiveness of strategies for the treatment of intestinal parasites in immigrants. New England Journal of Medicine 1999; 340: PubMedID DOI /NEJM Original Paper URL Indexing Status Subject indexing assigned by NLM MeSH Albendazole /economics /therapeutic use; Cost of Illness; Cost-Benefit Analysis; Decision Support Techniques; Drug Costs /statistics & numerical data; Emigration and Immigration; Feces /parasitology; Hospitalization /economics; Humans; Intestinal Diseases, Parasitic /diagnosis /drug therapy /economics /mortality; Mass Screening /economics; Models, Economic; Preventive Health Services /economics AccessionNumber Date bibliographic record published 31/03/2000 Date abstract record published 31/03/2000 Page: 5 / 5