Clinical and prognostic implications of serum uric acid levels on IgA nephropathy: a cohort study of 348 cases with a mean 5-year follow-up

AIM To assess the prognostic implications of serum uric acid levels on patients with IgA nephropathy in a longitudinal 8-year follow-up study and to identify an association between serum uric acid levels and the clinical and pathological phenotypes of IgA nephropathy. SUBJECTS AND METHODS We reviewed the files of all consecutive patients with IgA nephropathy treated at our hospital between 2001 and 2009. Analyses were performed to investigate the association between the level of serum uric acid and both clinical and pathological phenotypes of IgA nephropathy. Prognosis was assessed based on follow-up data. RESULTS At the same glomerular filtration rate (GFR), there was no significant difference in the levels of 24 hours proteinuria, blood urea nitrogen (BUN), and serum creatinine between the two groups with different levels of serum uric acid (p > 0.05). The prevalence of glomerular sclerosis as well as the scores of tubulointerstitial and vascular injury was greater in patients with high serum uric acid levels compared to patients with normal levels of serum uric acid (p < 0.05). At the end of the follow-up period, patients with high serum uric acid levels had a higher prevalence of reduced GFR and end stage renal disease (ESRD) than those with normal serum uric acid levels (40.82 vs. 15.70% and 64.71 vs. 35.00%, respectively; p < 0.05). CONCLUSIONS The serum uric acid level in patients with IgA nephropathy affects the pathophysiology and prognosis of the disease. We also identified a correlation between hyperuricemia and a higher risk of renal end points.