The Role Of Serum Uric Acid Level In The Progression And Prognosis Of IgA Nephropathy

Objective: To explore the relationship between serum uric acid level and the clinical and pathological characters of Ig A nephropathy,and to assess the role of serum uric acid level in the progression and prognosis of Ig A nephropathy.Methods: From January 2015 to May 2016,a total of 208 patients with primary IgA nephropathy at Tongji Hospital,Huazhong University of Science and Technology were involved in this study and classified into hyperuricemia(HUA)group and normo-uricemia(NUA)group according to the plasma uric acid level.The differences in clinical indicators and histopathological features(including Ig A nephropathy Oxford classification scores,glomerular sclerosis proportion,vascular lesion scores,etc.)between the two groups were compared.All patients were followed up,and the prognosis of the patients was evaluated by Kaplan-Meier survival curves based on follow-up data.Cox regression analysis was used to determine the risk factors for prognosis of Ig A nephropathy.Data analysis and mapping were performed by SPSS 23.0 and Graph Pad Prism 7.0 software.Results: In clinical indicators,the proportion of males to females,body mass index,systolic blood pressure,diastolic blood pressure,mean arterial pressure,incidence of hypertension,the levels of cholesterol,triglycerides,serum creatinine,blood urea nitrogen,24 hour-urine protein,complement C3 and complement C4 in the HUA group were significantly higher than those in the NUA group while the levels of high-density lipoprotein cholesterol and the estimated glomerular filtration rate were significantly lower than those in the NUA group(p<0.05).In terms of pathological characteristics,the tubular atrophy/interstitial fibrosis scores,vascular injury scores,and glomerular sclerosis percentage were significantly higher in the HUA group compared with those in the NUA group(p<0.01).There were no significant differences in the mesangial hypercellularity scores,endocapillary hypercellularity scores,focal segmental glomerulosclerosis scores as well as crescents scores between the two groups(p>0.05).As for the depositions of immune complexes deposition in Ig A nephropathy,the HUA group had lower deposition of immunoglobulin G than NUA group(p=0.0239),while the deposition of immunoglobulin A,immunoglobulin M,and complement C3 in the two groups showed no statistical difference.The Kaplan-Meier survival curve suggested that the cumulative renal survival rate of the HUA group was significantly lower than that of the NUA group(p=0.0147).Cox multivariate regression analysis showed that high level of serum uric acid and creatinine,large amount of urinary protein at renal puncture were independent risk factors for poor prognosis of Ig A nephropathy(HR 1.146,4.860 and 1.482,respectively,p<0.05).Conclusions: Hyperuricemia is an independent risk factor for poor prognosis of Ig A nephropathy,and is associated with renal function level and pathological severity of Ig A nephropathy at renal biopsy.