MO315CLINICAL AND PATHOLOGICAL FEATURES OF IGA NEPHROPATHY: A REPORT FROM A SINGLE CENTER
Authors: Lima Anna , Santos Afonso , Brás Catarina , Manso Rita , Campos Pedro , Carrilho Patrícia , Soto Rios Miriam Karina 
Published: May 2021

Abstract

Background and Aims
IgA nephropathy (IgAN) is one of the most prevalent glomerulopathies worldwide with broad variable clinical presentation and extremely heterogeneous risk of progressive CKD and ESKD. It was recommended risk stratifying patients in order to target immunosuppressive treatment to high-risk patients. The OXFORD MEST classification and, more recently, a new international risk-prediction tool for IgAN (IgANPT) help to predict kidney outcomes and stratify patient risk, eventually aiding in treatment decision. Here, we analyzed a single center cohort of IgAN to investigate if treatment decisions were accurately accomplished using individualized risk from the IgANPT.

Method
A retrospective analysis of all kidney biopsies performed from January 2010 to December 2019 in a Nephrology Department was performed and adult patients with IgAN diagnosis were selected. The presence of IgA vasculitis and Henoch-Schönlein purpura as well as lack of follow-up data were exclusion criteria. Clinical, laboratorial and pathological data were collected, including treatment and kidney outcome. Risk of kidney progression decline was assessed by using the on-line web-based calculator of the IgANPT.

Results
A total of 33 patients met the study criteria, with median age at diagnosis of 58 (IQR 38 - 68) years-old, mostly male (84,8%, N=28) and all Caucasian. At biopsy time 60,6% (N=20) had hypertension, only 15,5% (N=5) diabetes mellitus and 57,6% (N=19) were under ACE inhibitors/ARBs. Median GFR at biopsy time was 57 (IQR 20 - 78,5) ml/min/1.73m2. More than half of the patients (57,6%, N=19) had GFR &lt;60ml/min/1.73m2. All patients had proteinuria (UACR &gt; 300mg/g), with 18,2% (N=6) in the nephrotic range. Hematuria was present in almost all patients.
Overall MEST classification was: 51,5% (N= 17) with M1 score, 39,4% (N=13) E1, 66,7% (N=22) S1 and 45,5% (N=15) had T ≥1 score (2 patients with T2). Crescents were present in 27,3% of the biopsies (N=9). Near one-half of the patients (45,5%, N=15) presented IgA deposits on both mesangium and capillary wall.
Around one-third of patients (30,3%, N=10) progressed to ESKD during follow up. According to the risk of kidney disease progression in 60-months calculated with IgANPT, patients were stratified into low/intermediate risk in 21,2% (N=7) of cases (mean predicted risk &lt; 4,7%) and high risk in 78,8% (N=26) of cases (mean predicted risk &gt; 4,7%). Using the chi-squared test the high-risk group was associated with progression to ESKD(p=0,019). On the contrary none of the low-risk group progressed to ESKD.
The majority of patients received supportive treatment (87,9%, N= 29), mainly with ACEi/ARB (N=31) and omega (15,2%, N=5). Immunosuppressive treatment included mainly corticosteroids (51,5%, N=17), with other options being (12,1% N=4): cyclophosphamide (N=2), ciclosporin (N=1) and MMF (N=1).
From the group of low/intermediate risk patients, only two (28,5%) received immunosuppressive treatment with either oral or intravenous corticosteroids. On the other hand, from the high-risk group, more than one third of patients (38,4%, N=10) did not receive immunosuppressive treatment.

Conclusion
A better prediction of kidney outcomes and consequent better patient selection for IS therapy may be challenging in IgA nephropathy. In spite of the existent tools, it is still difficult to determine which patients benefit from immunosuppressive treatment. In this case series we stratified our patients by using the IgANPT identifying who was at higher risk of progression to ESKD, in whom, a more aggressive treatment could have potentially benefit avoiding kidney disease progression. It was also important to stratify patients at low-risk, in whom immunosuppressive treatment could carry risk of adverse events with no additional advantage in kidney outcomes.