The cost-effectiveness of HLA-B*5801 screening to guide initial urate-lowering therapy for gout in the United States

Objective Positive HLA-B*5801 carriers are at greater risk of experiencing rare but severe allopurinol hypersensitivity syndrome (AHS) [i.e., Stevens–Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN)]; however, HLA-B*5801 prevalence and AHS risk vary by race/ethnicity. We evaluated the cost-effectiveness of HLA-B*5801 testing according to race/ethnicity in the United States. Methods We determined the cost-effectiveness of universal testing for HLA-B*5801 compared to no testing prior to the initiation of allopurinol per US major race/ethnicity groups. Using US-specific data, SJS/TEN risks and HLA-B*5801 prevalences were modeled per race/ethnicity (i.e., 1/3846 and 0.7% among Caucasians and Hispanics, 1/735 and 3.8% among African Americans, and 1/336 and 7.4% among Asians, respectively). Those who tested positive for HLA-B*5801 received febuxostat. Costs, quality-adjusted life-years (QALYs), and incremental cost-effectiveness ratios (ICERs) were estimated over a lifetime. Results Compared to no testing, universal testing for HLA-B*5801 costs more and was more effective for all races/ethnicities. The ICERs varied substantially across racial/ethnic groups, following their HLA-B*5801 prevalences. HLA-B*5801 testing was cost-effective for African Americans (ICER $83,450) and Asians (ICER $64,190), but not for Caucasians or Hispanics (ICER $183,720), using accepted US willingness-to-pay threshold ($109,000/QALY). Results were robust in sensitivity analyses, except that reducing the risk of SJS/TEN by a half made testing not cost-effective for all races/ethnicities. Conclusion Testing for HLA-B*5801 prior to allopurinol initiation is cost-effective for Asians and African Americans, but not for Caucasians or Hispanics in the United States. Reducing AHS risk by other predictive measures could make HLA-B*5801 testing not cost-effective even among Asians and Blacks.