No Increase in CKD Risk with Allopurinol for Gout

For patients with gout, starting urate-lowering therapy with allopurinol does not appear to lead to an increased risk of developing stage 3 or higher chronic kidney disease (CKD), reports a study in JAMA Internal Medicine.

Using a UK general practice database, the researchers identified two propensity-score matched groups of patients with newly diagnosed gout. One group of 4760 patients initiated urate-lowering treatment with allopurinol. The comparison group included the same number of patients who did not receive allopurinol. About 83% of patients in both groups were men. Mean age was 57 years and mean body mass index was 30. All patients had initially normal or near-normal kidney function.

The main outcome of interest was the development of stage 3 or higher CKD. Mean follow-up was 5 years in patients who initiated allopurinol and 4 years in the comparison group.

Patients starting allopurinol at a dose of at least 300 mg/d were less likely to develop stage 3 or higher CKD: adjusted hazard ratio 0.87. There was little or no difference in the association after additional adjustment for the covariates included in the propensity score. At initial doses of less than 300 mg/d, allopurinol therapy showed no association with decline in renal function.

Only one-third of patients with gout receive urate-lowering therapy; the problem of undertreatment is compounded by frequent comorbidity with CKD. Physicians are cautious about using allopurinol in patients with gout, especially those with declining renal function. There is a lack of data on the renal effects of allopurinol in gout patients with normal renal function.

This large study analysis of primary care data finds a reduced risk of stage 3 CKD among newly diagnosed gout patients starting on allopurinol, 300 mg/d or higher. The researchers discuss their findings in the context of the ongoing suboptimal treatment of gout. They conclude: “Because allopurinol does not appear to be associated with renal function decline, clinicians should consider evaluating other potential causes when patients with gout experience renal function decline” [Vargas-Santos AB, et al. Association of chronic kidney disease with allopurinol use in gout treatment. JAMA Intern Med 2018; 178:1526–1533].

December 2018 (Vol. 10, Number 12)