Cost effectiveness of human immunodeficiency virus postexposure prophylaxis for healthcare workers Scheid D C, Hamm R M, Stevens K W

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1 Cost effectiveness of human immunodeficiency virus postexposure prophylaxis for healthcare workers Scheid D C, Hamm R M, Stevens K W 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 Human immunodeficiency virus (HIV) postexposure prophylaxis (PEP) for health care workers. Type of intervention Treatment. Economic study type Cost-effectiveness analysis; cost-utility analysis. Study population The study population was health care workers exposed to HIV-infected blood. Setting The study setting was hospital. The economic study was carried out in the USA. Dates to which data relate Effectiveness and resource use data were collected from studies published between 1986 and Cost data were collected from studies published between 1993 and The price year was Source of effectiveness data Effectiveness evidence was derived from a review of the literature. Modelling A Markov decision analytic model was used to determine the cost-effectiveness of the PEP strategies. Outcomes assessed in the review The review assessed the following outcomes: exposure characteristics, exposure classification, transmission probabilities, treatment efficacy, acceptance of therapy by regimen, and utilities. Study designs and other criteria for inclusion in the review The exposure categories were derived from large surveillance studies. Sources searched to identify primary studies Page: 1 / 5

2 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 17 primary studies were included in the review. Methods of combining primary studies Primary studies were combined using the narrative method. Investigation of differences between primary studies Results of the review The exposure probabilities were as follows: percutaneous exposure 66.1%, penetrating exposure 80%, blood visible on device 30.9%, mucocutaneous large volume 11.7%, source patient with terminal AIDS 18.3%. The probabilities of exposure classification ranged from EC3 (more severe percutaneous) (16.4%) to SC2 (higher titre exposure) (18.3%). The transmission probabilities were as follows: percutaneous exposure 0.32%, mucocutaneous exposure 0.026%, expanded regimen eligible 0.72%, basic regimen eligible 0.08%, consider basic regimen 0.05%, and no regimen recommended 0.009%. The seroconversion percentages were as follows: with monotherapy 21%, double therapy 15.5%, and triple therapy 10%. The acceptance percentages were as follows: expanded regimen 76%, basic regimen 76%, and consider basic regimen 21%. The probability of completing therapy was 69%. The number of days of partial completion was 8. The zidovudine resistance rate was 17.5%. The probability of major adverse effects was 0.001%. The duration of HIV stages varied between 1.03 and 5.6 years. The percentage quality of life for HIV varied between 17% and 83%. Measure of benefits used in the economic analysis Three measures of benefit were used: HIV infections, years of life saved, and quality adjusted life years (QALYs). Benefit measures were discounted at an annual rate of 0%, 3%, and 5%. Quality of life adjustments for HIV disease Page: 2 / 5

3 were based on a survey of health care workers using a time trade-off method. Direct costs Direct costs were discounted at an annual rate of 0%, 3%, and 5%. Quantities and costs were reported separately. Direct costs included costs of postexposure counselling (periodic office visits and HIV testing according to the recommended schedule), costs of PEP (costs of drugs, periodic office visits, toxicity monitoring), average health care costs of HIVseropositive adults and the average health care costs of all adults. The quantity/cost boundary adopted was that of society. The estimation of quantities and costs was based on actual data. Costs and quantities were collected from published studies. The price year was Statistical analysis of costs No statistical analysis of costs was reported. Indirect Costs Indirect costs were not included. Currency US dollars ($). Sensitivity analysis A one-way sensitivity analysis was performed for transmission rates of each exposure category, efficacy of double and triple therapy, the probability of acceptance of PEP, the cost of antiviral drugs, quality of life and the cost of health care for HIV-seropositive health care workers. A multiway sensitivity analysis was performed using a Monte Carlo simulation. Estimated benefits used in the economic analysis The number of infections prevented per 1,000 health care workers compared with no PEP was 2.08 with monotherapy, 2.21 with USPHS PEP therapy, and 2.22 with triple therapy. The number of life years saved per 1,000 health care workers compared with no PEP was 31.2 with monotherapy, 33.0 with USPHS PEP therapy, and 33.2 with triple therapy. The number of QALYs saved per 1,000 health care workers compared with no PEP was 33.6 with monotherapy, 35.6 with USPHS PEP therapy, and 35.8 with triple therapy. Cost results Total costs per 1,000 health care workers of monotherapy varied between a cost saving of $16,000 and a cost of $98,000. Total costs per 1,000 health care workers of USPHS varied between $140,000 and $261,000. Total costs per 1,000 health care workers of triple therapy varied between $267,000 and $261,000. Synthesis of costs and benefits The cost per QALY saved was $688 (95% CI: ) for monotherapy, $5,211 (95% CI: 5,126-5,293) for USPHS recommendations, and $8,827 (95% CI: 8,715-8,940) for triple drug therapy. Page: 3 / 5

4 The cost per year of life saved was $81,987 (95% CI: 80,437-83,689) for USPHS recommendations, and $970,451 (95% CI: 924,786-1,014,429) for triple drug therapy. The analysis was sensitive to the probability of seroconversion and to the costs of treatment for HIV infections, but these did not affect the order of preferred strategies. Authors' conclusions Current USPHS PEP recommendations are marginally cost-effective compared with monotherapy, but the additional efficacy of triple drug therapy for all risk categories is rewarded by only a small reduction in HIV infections at great expense. CRD COMMENTARY - Selection of comparators A justification was given for the comparator used, namely no treatment. The treatment strategies were also compared in a stepwise manner. You, as a user of the database, should decide if these health technologies are relevant to your setting. Validity of estimate of measure of benefit The authors did not state that a systematic review of the literature had been undertaken. More information about the design of the review and the method of combining primary effectiveness estimates could have been reported. Estimation of benefits was modelled using a Markov model, which was appropriate. The instrument used to derive the measure of health benefit, the time trade-off, was appropriate. Validity of estimate of costs Good features of the cost analysis were that all relevant direct cost categories were included (including the costs of side effects), sensitivity analyses were conducted on costs and quantities, quantities and costs were reported separately, and the price year was reported. However, it was unclear whether charges were used to proxy prices. Other issues The authors did make appropriate comparisons of their findings with those from other studies but did not address the issue of generalisability to other settings. The authors did not present their results selectively. The study considered exposed health care workers and this was reflected in the authors' conclusions. The authors did not consider healthrelated losses of productivity. They also acknowledged that the model only considered exposure of a health care worker to a source for which the HIV status was known. Finally, the measure of quality of life for HIV stages was estimated on the basis of a small survey of health care providers. Implications of the study For the foreseeable future, assuming innovations in therapy that employ expensive drug combinations earlier in the HIV disease course to extend life expectancy and the increasing prevalence of HIV drug resistance, the model supports the use of the USPHS PEP guidelines. Source of funding None stated. Bibliographic details Scheid D C, Hamm R M, Stevens K W. Cost effectiveness of human immunodeficiency virus postexposure prophylaxis for healthcare workers. PharmacoEconomics 2000; 18(4): PubMedID Page: 4 / 5

5 Powered by TCPDF ( Indexing Status Subject indexing assigned by NLM MeSH Cost-Benefit Analysis; HIV Infections /prevention & control /transmission; Health Care Costs; Health Personnel; Humans; Occupational Diseases /prevention & control; Probability AccessionNumber Date bibliographic record published 31/08/2001 Date abstract record published 31/08/2001 Page: 5 / 5