Allopurinol not linked to worsening kidney function in gout patients
medwireNews: Study findings published in JAMA Internal Medicine suggest that allopurinol use is not associated with renal function decline among patients with gout.
“[C]linicians are often cautious about using allopurinol” in patients with chronic kidney disease (CKD), and “commonly hold or lower the dose of allopurinol or even discontinue allopurinol entirely when a patient with gout exhibits kidney function decline,” despite there being “no clear data to suggest that allopurinol is detrimental to renal function”, say Tuhina Neogi (Boston University School of Medicine, Massachusetts, USA) and colleagues.
In an analysis of data from The Health Improvement Network (THIN), the researchers demonstrated that 12.2% of 4760 UK primary care patients with newly diagnosed gout who initiated allopurinol treatment at a dose of at least 300 mg/day developed stage 3 or higher chronic kidney disease (CKD) over an average follow-up of 5 years.
By comparison, 13.1% of their 4760 propensity score-matched counterparts who did not initiate allopurinol developed stage 3 or higher CKD over a mean of 4 years, translating into a significant 12% reduced risk among those given allopurinol after adjustment for factors including duration of gout, baseline kidney function, and the use of other medications.
The 10,179 patients who initiated allopurinol at a dose below 300 mg/day had the same risk of developing stage 3 or higher CKD as the matched patients who did not initiate allopurinol, however, a finding that was “consistent with current thinking that most patients need doses higher than 300 mg/d to achieve clinically meaningful outcomes”, write the study authors.
“Nonetheless, at minimum, allopurinol does not seem to have a detrimental effect on renal function in individuals with gout”, they add.
Neogi and colleagues say that their study could have been subject to “surveillance bias unfavorable to allopurinol use” because patients receiving allopurinol visited their primary care provider more regularly than nonusers (20.5 vs 18.3 visits), and had their glomerular filtration rate measured more often on average (4.7 vs 4.0 assessments) over the follow-up period.
“Thus, allopurinol users could be more readily diagnosed with CKD simply on the basis of having laboratory tests assessed more frequently and over a longer period, making our findings conservative”, they write.
And the team concludes that “clinicians should consider evaluating other factors when faced with renal function decline in their patients with gout rather than lowering the dose of or discontinuing allopurinol, a strategy that has contributed to the ongoing suboptimal treatment of gout.”
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