Clinicopathological Characteristics, Role of Immunosuppressive Therapy and Progression in IgA Nephropathy with Hyperuricemia

BACKGROUND/AIMS: The aim of the study was to investigate clinicopathological characteristics, the role of immunosuppressive therapy and renal outcome in IgA nephropathy (IgAN) patients with hyperuricemia. METHODS: 206 biopsy-proven primary IgAN patients were included between January 2010 and December 2015, and divided into two groups: patients without hyperuricemia (n=122), and patients with hyperuricemia (n=84). The clinicopathological features, response, renal outcome and safety were recorded. In univariate and multivariate models, hyperuricemia-associated pathological factors were analyzed. RESULTS: The patients with hyperuricemia presented higher systolic blood pressure, worse kidney function and more severe time-averaged proteinuria. Proportions of glomerulosclerosis, segmental glomerulosclerosis, tubular atrophy/interstitial fibrosis, lymphocytes and monocytes infiltration were higher, while the proportion of segmental adhesion was lower in patients with hyperuricemia. By multivariate logistic regression analysis, only tubular atrophy/interstitial fibrosis (T1∼2) (HR=3.969, 95% CI=1.439-10.945, P=0.008) was significantly associated with hyperuricemia. For hyperuricemic patients, the response rate to therapy and renal survival rate were significantly higher in patients that received RAS blockade in combination with immunosuppressive therapy. After RAS blockade treatment, renal survival in the patients with hyperuricemia was worse compared with the patients without hyperuricemia. CONCLUSION: Hyperuricemic IgAN patients presented more severe clinical features. Tubulointerstitial injury could be a pathological feature closely related to hyperuricemia in IgAN. Immunosuppressive therapy and RAS blockade could reduce proteinuria and improve renal outcome in IgAN patients with hyperuricemia.