title: Cost-effectiveness analysis of HLA-B*5801 testing in preventing allopurinol-induced SJS/TEN in Thai population.
abstract: BACKGROUND
  Stevens-Johnson syndrome (SJS) and Toxic Epidermal Necrolysis (TEN), caused by allopurinol therapy, are strongly associated with the human leukocyte antigen (HLA), HLA-B*5801. Identification of HLA-B*5801 genotype before prescribing allopurinol offers the possibility of avoiding allopurinol-induced SJS/TEN. As there is a paucity of evidence about economic value of such testing, this study aims to determine the cost-effectiveness of HLA-B*5801 testing compared with usual care (no genetic testing) before allopurinol administration in Thailand.
  
  
  RESULTS
  A decision analytical and Markov model was used to estimate life time costs and outcomes represented as quality adjusted life years (QALYs) gained. The model was populated with relevant information of the association between gene and allopurinol-induced SJS/TEN, test characteristics, costs, and epidemiologic data for Thailand from a societal perspective. Input data were obtained from the literature and a retrospective database analysis. The results were expressed as incremental cost per QALY gained. A base-case analysis was performed for patients at age 30. A series of sensitivity analyses including scenario, one-way, and probabilistic sensitivity analyses were constructed to explore the robustness of the findings. Based on a hypothetical cohort of 1,000 patients, the incremental total cost was 923,919 THB (USD 29,804) and incremental QALY was 5.89 with an ICER of 156,937.04 THB (USD 5,062) per QALY gained. The cost of gout management, incidence of SJS/TEN, case fatality rate of SJS/TEN, and cost of genetic testing are considered very influential parameters on the cost-effectiveness value of HLA-B*5801 testing.
  
  
  CONCLUSIONS
  The genetic testing for HLA-B*5801 before allopurinol administration is considered a highly potential cost-effective intervention in Thailand. The findings are sensitive to a number of factors. In addition to cost-effectiveness findings, consideration of other factors including ethical, legal, and social implications is needed for an informed policy decision making.
authors.affiliation: Center of Pharmaceutical Outcomes Research (CPOR), Department of Pharmacy Practice, Faculty of Pharmaceutical Sciences, Naresuan University, Phitsanulok, Thailand; Center of Health Outcomes Research and Therapeutic Safety (Cohorts), School of Pharmaceutical Sciences, University of Phayao, Phayao, Thailand; Pharmacotherapy Outcomes Research Center (PORC), College of Pharmacy, University of Utah, Salt Lake City, Utah, United States of America.
authors.forename: Surasak
authors.initials: S
authors.lastname: Saokaew
authors.affiliation: Department of Pharmacology, Faculty of Medicine, Khon KaenUniversity, Khon Kaen, Thailand; Research and Diagnostic Center for Emerging Infectious Diseases, Khon Kaen University, Khon Kaen, Thailand.
authors.forename: Wichittra
authors.initials: W
authors.lastname: Tassaneeyakul
authors.affiliation: Clinical Pharmacy Research Unit, Department of Clinical Pharmacy, Faculty of Pharmacy, Mahasarakham University, Mahasarakham, Thailand.
authors.forename: Ratree
authors.initials: R
authors.lastname: Maenthaisong
authors.affiliation: Center of Pharmaceutical Outcomes Research (CPOR), Department of Pharmacy Practice, Faculty of Pharmaceutical Sciences, Naresuan University, Phitsanulok, Thailand; School of Pharmacy, University of Wisconsin, Madison, Wisconsin, United States of America; School of Pharmacy, Monash University Malaysia, Bandar Sunway, Selangor, Malaysia; School of Population Health, University of Queensland, Brisbane, Australia.
authors.forename: Nathorn
authors.initials: N
authors.lastname: Chaiyakunapruk
mesh_terms: D000493:Allopurinol / Q000009:adverse effects*; D003362:Cost-Benefit Analysis; D003661:Decision Support Techniques; D005820:Genetic Testing / Q000191:economics*; D015235:HLA-B Antigens / Q000191:economics* / Q000235:genetics*; D006801:Humans; D013262:Stevens-Johnson Syndrome / Q000191:economics / Q000235:genetics* / Q000517:prevention & control*; D013785:Thailand; D016896:Treatment Outcome
chemical_list: D015235:HLA-B Antigens; D000493:Allopurinol
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