The health burden of gout continues to rise in Canada.[1] Allopurinol, a common urate-lowering medication used to treat gout, is associated with severe adverse cutaneous drug reactions (SCARs) in specific at-risk populations, primarily people of East Asian descent. SCARs include Stevens-Johnson syndrome, toxic epidermal necrolysis and drug reaction with eosinophilia and systemic symptoms, and lead to elevated morbidity/mortality and long-term sequelae. Two recent Canadian publications[2,3] have highlighted the importance of screening at-risk populations for the development SCARs. The American College of Rheumatology guidelines recommend screening East Asian patients for the HLA-B*58:01 genotype prior to prescribing allopurinol, to eliminate the risk of SCARs in this population.[4,5] Unfortunately, HLA-B*58:01 genotype testing is underutilized in British Columbia despite East Asians comprising a substantial proportion of the population.[2] Other risk factors for SCARs in individuals prescribed allopurinol include heart disease and chronic kidney disease.[3]

The cost-effectiveness of preventive HLA screening for East Asians prior to allopurinol has been established in various populations globally and this screening needs to be more widely adopted in Canada. In British Columbia, HLA-B*58:01 genotype screening can be ordered by sending blood tests to BC Transplant, the laboratory in charge of HLA genotyping. Other therapeutic options for the control of hyperuricemia include feboxustat and uricosurics. We believe that not performing this test prior to the prescription of allopurinol may cause your Asian patients serious harm.
—Marisa Ponzo, MD-PhD, FRCPC
Vancouver
—Jan Dutz, MD, FRCPC
Vancouver

References

1.    Rai SK, Aviña-Zubieta JA, McCormick N, et al. Trends in gout and rheumatoid arthritis hospitalizations in Canada from 2000 to 2011. Arthritis Care Res (Hoboken) 2017;69:758-762.

2.    Ponzo MG, Miliszewski M, Kirchhof MG, et al. HLA-B*58:01 genotyping to prevent cases of DRESS and SJS/TEN in East Asians treated with allopurinol—A Canadian missed opportunity. J Cutan Med Surg 2019;23:595-601.

3.    Yokose C, Lu N, Xie H, et al. Heart disease and the risk of allopurinol-associated severe cutaneous adverse reactions: A general population-based cohort study. CMAJ 2019;191:E1070-E1077.

4.    Khanna D, Fitzgerald JD, Khanna PP, et al. 2012 American College of Rheumatology guidelines for management of gout. Part 1: Systematic non-pharmacologic and pharmacologic therapeutic approaches to hyperuricemia. Arthritis Care Res (Hoboken) 2012;64:1431-1446.

5.    Khanna D, Khanna PP, Fitzgerald JD, et al. 2012 American College of Rheumatology guidelines for management of gout. Part 2: Therapy and anti-inflammatory prophylaxis of acute gouty arthritis. Arthritis Care Res (Hoboken) 2012;64:1447-1461.