Prevalence of Abacavir Hypersensitivity Reaction and Cost-Effectiveness of HLA-B*5701 Screening: A Ten-Year Experience in The HRH Princess Maha Chakri Sirindhorn Medical Center

Abstract

Background: Recently, the authors had reported a case with abacavir hypersensitivity reaction (ABC-HSR), the first diagnosed patient at the HRH Princess Maha Chakri Sirindhorn Medical Center (MSMC). There was no data regarding the incidence or prevalence of ABC-HSR previously reported in Thailand. Objective: To study the prevalence of ABC-HSR, the abacavir use pattern and the cost effectiveness for the routine human leukocyte antigen (HLA)-B*5701 screening before abacavir use by analyses of the MSMC data. Materials and Methods: All patients at the MSMC who were prescribed abacavir from October 1, 2010 to September 30, 2020 were retrospectively reviewed for ABC-HSR and the abacavir use pattern at the time when abacavir was started. The cost-effectiveness analysis was applied by analyzing the cost between the routine HLA-B*5701 screening before abacavir use and the HLA-B*5701 confirmation for ABC-HSR. The cost for the prevention of a case of ABC-HSR was defined. Results: There were total of 54 patients who were prescribed abacavir and only one ABC-HSR case diagnosed. The prevalence of ABC-HSR was 1.85%. The main reason for the abacavir prescription was a substitution for tenofovir (TDF) because of the TDF adverse effects (81.13%). The HLA-B*5701 screening before abacavir use was done in 26.42% at the MSMC. If all eligible patients were routinely screened for the HLA-B*5701 allele before abacavir use, the cost would be 54,000 Baht. The cost for the diagnosis and the management of the ABC- HSR case was 7,230 Baht. The cost for the prevention of a case of ABC-HSR was 46,770 Baht. Conclusion: The prevalence of ABC-HSR was low. The main reason for abacavir use was a substitution for TDF. The cost for the prevention for a case of ABC-HSR was 46,770 Baht which would be less if the cost for the HLA-B*5701 test was reduced. Keywords: Abacavir; Hypersensitivity reaction; Prevalence; HLA-B*5701