Background Although uncommon, the most feared adverse event of urate-lowering drugs (ULDs) is allopurinol hypersensitivity syndrome (AHS), primarily manifesting as Stevens-Johnson Syndrome (SJS) and Toxic Epidermal Necrolysis (TEN). HLA-B*5801 allele carriage (a strong determinant of AHS) varies substantially among races, which may lead to major racial disparities in the risk of SJS/TEN in the context of ULD adverse events (ULDAEs). Such information could immediately help risk stratification to prevent these severe ULDAEs.
Objectives To examine potential racial disparities in the risk of SJS/TEN in the context of ULDAEs in a large, racially diverse, and generalizable population.
Methods Using the Nationwide Inpatient Sample (NIS, 2009–2013), a database representative of all US hospitalizations, we examined the racial distribution of hospitalized SJS/TEN (principal discharge diagnosis) as ULDAEs (ICD-9-CM Classification of External Causes); this combination implicates allopurinol, which is the only ULD established to cause SJS/TEN. Our reference groups were the US Census population, US allopurinol users (from the NHANES), and ULDAE hospitalizations without SJS/TEN (from the NIS).
Results We identified 606 patients hospitalized for SJS/TEN as ULDAEs meeting our criteria between 2009–2013 (mean age, 68 years; 44% male). Of these 606 patients, there was a substantial over-representation of Asians (27%) and Blacks (26%), and an under-representation of Whites (29%) and Hispanics (% too-low-to-report), compared with the US Census population (5%, 12%, 67%, and 15%, respectively). The hospitalization rate ratios for SJS/TEN among Asians, Blacks, and Whites were 11.9, 5.0, and 1.0 (referent), respectively. These associations persisted using other national referents (allopurinol users and ULDAE cases without SJS/TEN).
Conclusions These national data indicate that Asians and Blacks have a substantially higher risk of SJS/TEN as ULDAEs than Whites (or Hispanics), correlating well with corresponding frequencies of HLA-B*5801 in the US population (i.e.,7.4%, 4%, 1%, and 1% among Asians, Blacks, and Whites, Hispanics, respectively). As no other ULDs available in the US have been established to cause SJS/TEN, these findings support the use of vigilance in these minorities when considering allopurinol.
Disclosure of Interest None declared