Role of Uric Acid in Post-Renal Transplantation Hypertension

Uric acid (UA) is an emerging cardiovascular (CV) risk factor that is associated with hypertension and CV disease (CVD) in the general population, but whose role in renal transplant recipients (RTR) has not been defined. We performed a retrospective chart review of 589 stable RTR receiving ongoing posttransplant care at our hospital, identifying those with a minimum of 3 serum UA measurements obtained at least 2 months posttransplantation, 6 months graft survival, stable renal function, and no change in antihypertensive or immunosuppressive drugs over this time. Data were collected for the period November 2005 to July 2007. Relationships were assessed by Pearson's correlation coefficient, and correlates of UA including blood pressure (BP) were determined using multiple linear regression analysis. There were 464 RTR who met eligibility criteria for the study. Hyperuricemia was present in 196 patients (42%). By Pearson's correlation coefficient, UA was inversely correlated with estimated glomerular filtration rate (eGFR; R = -.39; P < .0001) and directly correlated with C-reactive protein (CRP; R = .10; P = .02). However, UA did not correlate with either age (R = .07; P = .08) or systolic BP (R = .05; P = .76). Upon multivariate linear regression, UA was inversely associated with eGFR (P < .0001) and directly associated with male gender (P < .0001), use of cyclosporine (CsA; P = .0002), increasing time posttransplantation (P = .007), and CRP (P = .01). In summary, hyperuricemia is common in RTR, but was not related to BP. Further studies are required to establish whether UA predicts CV risk in this population.