Hyperuricemia in pediatric renal transplant recipients

We sought to evaluate the prevalence and confounding clinical variables of hyperuricemia in pediatric kidney transplant patients. We retrospectively evaluated the medical records of 151 pediatric renal transplant recipients who received their grafts at Akdeniz University Medical Faculty in Antalya, Turkey, with a follow-up longer than 6 months. This retrospective, single-center study included 117 pediatric renal transplant recipients, after we had excluded the patients with changes in immunosuppressive treatment and graft loss, who were receiving therapy with allopurinol and furosemide. Patient information and laboratory data were obtained from patient charts and an electronic hospital database. Mean uric acid levels of patients were 311 ± 74 μmol/L, and 24 of all of the patients (20%) had high uric acid levels. Fifteen patients taking tacrolimus (16%), and 9 of patients taking cyclosporine (39%) had hyperuricemia. The hyperuricemia rate of patients taking cyclosporine was significantly higher than it was for those patients taking tacrolimus (P = .014). Mean levels of uric acid in patients taking cyclosporine were higher than those of patients taking tacrolimus (344 ± 62 μmol/L and 303 ± 75 μmol/L; P = .006). There was a significant positive correlation between mean uric acid concentrations, and both serum creatinine (P = .000; r=0.487) and cystatin C (P = .000; r=0.433). There was negative correlation between mean uric acid concentration and estimated glomerular filtration rate (P = .000; r=-0.417). Mean uric acid levels of patients with intact graft function (estimated glomerular filtration rate ≥ 60 mL/min/1.73 m²) was lower than the patients with a low estimated glomerular filtration rate (291 ± 67 μmol/L and 353 ± 71 μmol/L; P = .000). Mean uric acid level of patients with normal body mass index was significantly lower than that of patients who were obese-overweight (301 ± 64 μmol/L vs 343 ± 94 μmol/L; P = .045). We found 20% of our patient group had high uric acid levels. We also found that lower glomerular filtration rate, higher serum creatinine, cystatin c, obesity, and being overweight were risk factors for hyperuricemia in pediatric renal transplant recipients.