Allopurinol-induced severe cutaneous adverse reactions (SCARs) are relatively rare but cause high rates of morbidity and mortality. Studies have shown that the HLA-B5801 allele and renal impairment are strongly associated with SCARs. Recent American College of Rheumatology guidelines recommend that, prior to treatment with allopurinol, the HLA-B5801 genotype of gout patients at high risk for SCARs, including Korean patients with chronic renal insufficiency, should be determined. However, whether such genotyping is cost-effective is unknown. This study evaluated the cost-effectiveness of HLA-B5801 genotyping for the treatment of gout in patients with chronic renal insufficiency in Korea.
A decision analytical model over a time period of 12 months was employed to compare the cost and outcomes of treatment informed by HLA-B5801 genotyping with that of a conventional treatment strategy using a hypothetical cohort of gout patients with chronic renal insufficiency. Direct medical costs were obtained from real patients with SCARs from 2 tertiary hospitals. Outcomes were measured as a total expected cost and an incremental cost-effectiveness ratio.
In the base model, the total expected cost and probability of continuation of gout treatment without SCARs for the conventional and HLA-B5801 screening strategies were $1,193 and 97.8% and $1,055 and 100%, respectively. The results were robust according to sensitivity analyses.
Our model suggests that gout treatment informed by HLA-B5801 genotyping is less costly and more effective than treatment without genotyping, and HLA-B5801 genotyping could considerably reduce the occurrence of allopurinol-induced SCARs and related deaths.