Serum uric acid concentration is associated with lower glomerular filtration rate in children undergoing kidney transplantation

Background: The relationship between serum concentration of uric acid (UA) and chronic kidney disease is complex due to many confounding variables. There is currently debate over whether hyperuricemia acts as a marker of kidney disease or as an independent risk factor.Objectives: To test the impact of serum UA concentration on the estimated glomerular filtration rate (GFR) of children undergoing kidney transplantation.Patients and Methods: Prospective longitudinal study of children and adolescents after kidney transplantation. We analyzed clinical, anthropometric, and laboratory data at pre-transplant and 1, 3, and 6 months after transplant. We developed models of repeated measures analysis, using the generalized estimating equations technique for the outcome evolution of the estimated GFR at 1, 3 and 6 months. High serum UA concentration at 1 and 3 months was modeled as the main exposure variable.Results: We included 103 transplant patients. In a model adjusted for time, recipient sex and age, the occurrence of acute rejection episodes, and the estimated glomerular filtration at baseline, the trajectory of GFR exhibited an inverse relationship with UA (beta = -7.1, 95% CI: -11.5 to -2.6, p < .01).Conclusion: Serum UA increase was associated with lower graft function over time.