Uric acid contributes to glomerular filtration rate deterioration in renal transplantation.

BACKGROUND

Many studies have been performed in kidney transplant recipients to test whether hyperuricemia plays a role in decreased kidney function, but the results have been controversial. We conducted a retrospective cohort study to assess the predictors of hyperuricemia and how uric acid (UA) influences glomerular filtration rate (GFR) changes.

METHODS

556 patients who underwent kidney transplantation between January 1, 1990 and February 24, 2009, were included. Serum UA levels were routinely recorded every 3 months after transplantation. Hyperuricemia was defined as serum UA ≥ 6.0 mg/dl for women, and ≥ 7.0 mg/dl for men. A time-dependent covariate Cox model was used to assess the association of serial changes of estimated GFR (eGFR) and UA.

RESULTS

Multivariate analysis indicated that male gender, eGFR, and transplant duration were associated with higher mean UA levels. A time-dependent covariate Cox model indicated that initial eGFR level (hazard ratio: 1.001; p = 0.035) and previous UA level (hazard ratio: 1.454; p < 0.001) affected the subsequent eGFR level.

CONCLUSIONS

Our results indicated a predictive relationship between UA and eGFR based on the results of a time-dependent covariate Cox model that elevated serum UA precedes a graft dysfunction in kidney transplant recipients.