Serum Urate Lowering with Allopurinol and Kidney Function in Type 1 Diabetes
RCT (n=530) found no evidence of clinically meaningful benefits of serum urate reduction with allopurinol on kidney outcomes (mean decrease GFR =−3.0 vs. −2.5ml/min/1.73m2/year for allopurinol and placebo, respectively) among patients with early/moderate diabetic kidney disease.
Source:
New England Journal of Medicine
SPS commentary:
This is one of two studies in New England Journal Medicine addressing the use of urate-lowering therapy for the prevention of kidney disease progression. In the Controlled Trial of Slowing of Kidney Disease Progression from the Inhibition of Xanthine Oxidase (CKD-FIX), which enrolled patients who had stage 3 or 4 CKD with a rapid decline in the estimated GFR or clinically significant proteinuria at baseline, treatment with allopurinol had no significant effect on the rate of GFR decline.
According to an editorial, the potential role of uric acid in the progression of kidney disease has been argued about for decades and epidemiologic studies consistently implicate serum uric acid as a risk factor for CKD; though in one study, statistical correction for the effects of hypertension or cardiovascular disease caused the apparent interaction to fade. It suggests that the challenge in interpreting such evaluations is that if serum uric acid contributes to CKD progression in part by the exacerbation of hypertension or cardiovascular disease, then correcting for those contributions may substantially attenuate the association and obscure a mechanistic link. It notes that observational studies, have also found the association between elevated serum uric acid and progression of CKD is strongest in younger patients, those with less severe CKD, and those without proteinuria. It adds that intention-to-treat analyses, as in the current studies, provide guidance about the real-world efficacy of clinical interventions, but generalisations must be made with caution as these trials did not address urate-lowering therapy, either pharmacologic or dietary, in younger patients or in those with earlier stages of CKD; more high-quality RCTs are needed.