Session Type: ACR Poster Session C
Session Time: 9:00AM-11:00AM
Background/Purpose: Clinicians using allopurinol are always concerned about the risk of rare hypersensitivity reaction. Allopurinol and febuxostat are the two most common urate-lowering agents used for the treatment of hyperuricemia in gout. Population-based studies to estimate the risk of hypersensitivity reactions with allopurinol and febuxostat have not been done. Our objective was to describe the risk of hypersensitivity reactions with allopurinol and febuxostat.
Methods: We used the 5% Medicare Beneficiary sample (³65 years) from 2006-2012 to identify people with a new filled prescription for allopurinol or febuxostat or colchicine, with a baseline period of 365 days without either medication. We used Cox regression analyses to compare the hazard ratio (HR) of incident hypersensitivity reactions with allopurinol or febuxostat vs. colchicine use.
Results: Of the 68,230 new medication exposure episodes, 363 ended in a hypersensitivity reaction. Crude incidence rates of hypersensitivity reactions were as follows: allopurinol, 23.7; febuxostat, 30.7; and colchicine, 25.6 per 1,000 person-years. Incidence of hypersensitivity reactions was highest in the first 30 days of exposure to allopurinol or febuxostat, with a progressive reduction later. In multivariable-adjusted analyses, compared to colchicine, allopurinol, febuxostat and febuxostat + colchicine combination were associated with significantly higher hazard ratios of hypersensitivity reactions, 1.32 (95% CI, 1.10, 1.60) and 1.54 (95% CI, 1.12, 2.12) and 2.17 (95% CI, 1.18, 3.99), respectively. In multivariable-adjusted analyses limited to allopurinol users, compared to allopurinol start dose of <200 mg/day, allopurinol start dose of ³300 mg/day and diabetes were associated with significantly higher hazard of hypersensitivity reactions, 1.27 (95% CI, 1.12, 1.44), and 1.21 (95% CI, 1.00, 1.45).
Conclusion: In people 65 years or older, allopurinol and febuxostat increased the risk of hypersensitivity reactions. In allopurinol users, allopurinol start dose and diabetes increased this risk. Future studies need to examine as to why a higher start dose increases hypersensitivity risk.
To cite this abstract in AMA style:Singh JA, Cleveland J. Hypersensitivity Reactions with Allopurinol and Febuxostat in Adults 65 Years or Older: A Study Using the Medicare Claims Data [abstract]. Arthritis Rheumatol. 2017; 69 (suppl 10). https://acrabstracts.org/abstract/hypersensitivity-reactions-with-allopurinol-and-febuxostat-in-adults-65-years-or-older-a-study-using-the-medicare-claims-data/. Accessed October 19, 2021.
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ACR Meeting Abstracts - https://acrabstracts.org/abstract/hypersensitivity-reactions-with-allopurinol-and-febuxostat-in-adults-65-years-or-older-a-study-using-the-medicare-claims-data/