Value of Repeat Renal Biopsy in the Treatment and Prognosis of Patients With Severe Lupus Nephritis.

Abstract

Objective To investigate the value of repeat renal biopsy in the treatment and prognosis of nephrotic syndrome(NS)and acute kidney injury(AKI)following immunosuppressive therapy in patients with lupus nephritis(LN).Methods A retrospective analysis was conducted for the clinicopathological data and follow-up records of LN patients undergoing repeat renal biopsy at Peking Union Medical College Hospital from January 1,2009 to December 31,2021.Results A total of 76 patients(55 females,72.4%)were included in this study,with the mean age at the first biopsy being(29.0±10.4)years,the median inter-biopsy interval of 4.0(2.0,7.0) years,and the median total follow-up duration of 7.5(5.0,13.8)years.Pathological transformation occurred in 46(60.5%)patients,and 2 patients had comorbid diabetic nephropathy.At repeat renal biopsy,50(65.8%) patients presented NS.These patients demonstrated lower estimated glomerular filtration rate(eGFR)(P<0.001),higher chronicity index(CI)(P=0.029),and higher complement C3(P<0.001)and C4(P<0.001)levels than those with NS at the first renal biopsy(n=50).Among the 28(36.8%) patients with AKI at repeat renal biopsy,8(28.6%)experienced acute exacerbation of chronic renal insufficiency.These patients exhibited higher serum creatinine level(P=0.002),C4 level(P=0.033),CI(P=0.042),and prevalence of thrombotic microangiopathy(P=0.046)than the patients showing AKI at the first renal biopsy(n=16),while the activity index(AI)showed no significant difference(P=0.051).Over 50% of NS and AKI patients underwent treatment modifications post-repeat renal biopsy,with clinical remission rates comparable to those after the first renal biopsy(both P>0.05).Elevated CI(≥5,P=0.001)and serum creatinine(≥140 μmol/L,P<0.001)at repeat renal biopsy were identified as independent risk factors for poor prognosis.The patients with AKI at repeat renal biopsy had higher incidence of endpoint events than the non-AKI patients(P=0.015).Neither AKI at the first renal biopsy nor NS at both biopsies had significant associations with prognosis.Conclusions Repeat renal biopsy reveals not only sustained high disease activity but also accelerates chronic progression in LN patients,which underscore its critical role in guiding the therapy for severe LN post-immunosuppression.AKI,CI≥5,and serum creatinine ≥140 μmol/L at repeat renal biopsy are strongly associated with poor prognosis.