Clinicopathological features and renal outcomes of IgA nephropathy with acute tubulointerstitial nephropathy / 中华肾脏病杂志

ABSTRACT

Objective To evaluate the clinicopathological characteristics and outcomes of IgA nephropathy (IgAN) with acute tubulointerstitial nephropathy (ATIN).Methods Patients who were diagnosed as IgAN with ATIN and IgAN without ATIN by renal biopsy in Peking University First Hospital were enrolled.There were 74 cases of IgAN with ATIN,and seventy-four cases of IgAN without ATIN were enrolled based on stratified sampling (chosen by 1∶ 1).The two groups were well matched with age,gender,follow-up time,mesangial hypercellularity(M),endocapillaryhypercellularity (E),segmental glomerulosclerosis(S),tubular atrophy/interstitial fibrosis(T) and cellular/fibrocellular crescent(C).The clinicopathological characteristics and outcomes of two groups were retrospectively analyzed.A composite end point,defined as 30％ or 50％ estimated glomerular filtration rate (eGFR)decline and end stage renal disease (ESRD) was used.Renal function and proteinuria during follow-up were observed.Renal survival was calculated by Kaplan-Meier survival analysis and risk factors of progression were analyzed by using univariate and multivariate Cox regression models.Results Seventy-four cases of IgAN with ATIN and seventy-four cases of IgAN without ATIN were enrolled.Serum creatinine [(185.6±83.2) μmol/L vs (146.3 ±69.2) μmol/L,P=0.010] and incidence of acute kidney disease (AKD) (31.1％ vs 5.4％,P ＜ 0.001) were higher in IgAN with ATIN group than those in IgAN without ATIN group.Patients in ATIN group received more immunosuppressive treatment (86.5％vs 58.1％,P＜ 0.001).During 1 year after biopsy,mean eGFR increased significantly in IgAN with ATIN group [(39.7+ 14.6) ml· min-1· (1.73 m2)-1 vs (47.2+ 19.9) ml· min-1· (1.73 m2)-1,P=0.017],but mean eGFR was not statistic different in IgAN without ATIN group [(60.0±30.5) ml· min-1· (1.73 m2)-1 vs (59.0±31.7) ml· min-1· (1.73 m2)-1,P=0.567].Median follow-up was 23.0 months in IgAN with ATIN group,and Median follow-up was 30.0 months in IgAN without ATIN group.Incidence of composite end point had no significant differences between two groups.IgAN with ATIN was not the independent risk factor for end point.IgAN patients with ATIN were divided into two groups (with AKD and without AKD),then renal survival rate was higher (Log-rank test,x2=5.293,P=0.021) and the risk for composite end point decreased by 79.2％ (HR=0.208,95％CI 0.046-0.939,P=0.041) in the group with AKD.Conclusions In IgAN,there is a subgroup of patients with the specific pathological phenotype combined with ATIN.Compared with those without AKD,the risk for composite end point of IgAN patients with ATIN and AKD showed a 79.2％ decrease.