Urate-lowering treatment with allopurinol may help maintain graft function in kidney transplant recipients (KTRs) with elevated serum uric acid levels, a new study suggests.
In the ADOPTR study (Allopurinol Drug use on GFR and Proteinuria in Renal Transplantation Recipients), investigators randomly assigned 124 KTRs to receive allopurinol (300 mg once daily) or matched placebo. Mean serum uric acid levels significantly decreased from 6.98 mg/dL at baseline to 6.00 mg/dL at 24 weeks in the allopurinol group, but did not change significantly in the placebo group, Özlem Usalan, MD, and colleagues from Gaziantep University School of Medicine, Gaziantep, Turkey, reported in Transplant Immunology. In the allopurinol group, mean estimated glomerular filtration rate (eGFR; according to the Modification of Diet in Renal Disease study equation) significantly increased from 68.05 to 71.97 mL/min/1.73 m2and mean urinary albumin to creatinine ratio (UACR) significantly decreased from 325.14 to 319.29 mg/g. No meaningful kidney function changes occurred in the placebo group.
A multivariable regression analysis showed that uric acid reduction significantly correlated with UACR reduction (r = 0,473, β = 0.021) and eGFR increase (r =−0554 β = 0.016) in KTRs treated with allopurinol.
C-reactive protein (CRP) levels significantly increased over 24 weeks in the placebo group but not the allopurinol group.
“Our results seem to support the view that lowering circulating urate levels plays a role in improving kidney function in kidney transplant recipients,” Dr Usalan’s team concluded.
They acknowledged that elevated uric acid levels may reflect metabolic acidosis or other conditions, and not just hyperuricemia. Routine prophylaxis of asymptomatic hyperuricemia is not recommended in current guidelines.
Previous studies have yielded conflicting results on the use of allopurinol in patients at various stages of chronic kidney disease.
“Long-term follow-up studies will be useful in revealing the effect of allopurinol on uric acid management and kidney functions and proteinuria.”
Usalana O, Sahin AZ, Ozdemir O, et al. Effect of allopurinol drug use on GFR and proteinuria in patients with renal transplant recipients (ADOPTR study). Transpl Immunol. Published online March 1, 2022. doi:10.1016/j.trim.2022.101560