#1716 IgA nephropathy: our center's experience
Authors: Mendes Beatriz , Fonseca Francisca , Inácio António Silva , Piedade Ana , Domingues Patrícia , Soto Karina 
Published: May 2024

Abstract

Background and Aims
IgA Nephropathy (IgAN) is the most common primary glomerulopathy worldwide. In the last years, significant advances have been made in understanding its pathophysiology and developing newer promising treatments. The accuracy of the International Risk-Prediction Tool in IgAN (IRP-IgAN) was already validated. Herein, we retrospectively analysed the relation of this risk score and the kidney outcomes.

Method
We performed a single center retrospective observational cross-sectional study of patients with histological diagnosis of IgAN between 2015 and 2023 in Centro Hospitalar de Setúbal, aiming to describe the demography, clinical presentation, histological characteristics, treatment and follow up of our cohort. The International Risk-Prediction Tool in IgAN was applied for patient stratification.

Results
Twenty-eight patients were diagnosed with IgAN in this eight-year period. Mean age was 46 years-old (SD ±12.2) and 71.4% were male. The majority were Caucasian (n = 26) with only two patients of Asian e African descent, respectively. The mean calculated Charlson Comorbidity Index was 1.43 (SD ±1.5). Eighteen patients (64.3%) had known arterial hypertension, diabetes was seen only in 2 patients, obesity in 4 patients, and hepatitis B in 2 patients. No cardiovascular disease or cancer was documented. On presentation, 71.4% (n = 20) had hypertension, 14.3% (n = 4) presented with rapidly progressive renal insufficiency, and 14.3% (n = 4) presented with nephrotic syndrome. Two patients (7.1%) required dialysis on presentation. Also, the mean glomerular filtration rate (GFR) was 55.3 ml/min (SD ±31.9) and mean proteinuria level (protein-to-creatinine ratio) was 2.42g/g (SD ±2.41). Most patients had hematuria (82.1%), C3 consumption was seen in only one patient while 10 patients had isolated higher levels of IgA. Mean time between the first symptoms or documented clinical features and dedicated Nephrology consultation was 2.9 years (SD ±3.78). Regarding the histological data and considering de MEST-C score, 71.4% had mesangial hypercellularity in more than 50% of the glomerulus (M1), 25% had endocapillary hypercellularity (E1), 17% had segmental glomerulosclerosis of at least one glomerulus (S1), 7% had interstitial fibrosis or cortical atrophy in 25-50% of the cortical area (T1) and 11% in more than 50% (T2), 17.9% had crescents in less than 25% of the glomerulus (C1) and 2.6% in more than 25% (C2). Fibrinoid necrosis was noticed in 7.1% of the patients. The presence of IgA in the mesangium on IF was universal and 18 patients (64.3%) had C3 co-stain. Approximately half of the patients (46.4%) were already on angiotensin converting enzyme inhibitor (ACEI) or angiotensin receptor blockers (ARB) by the time of clinical presentation and nearly all (92.9%) by the time the diagnosis was established. SGTL-2 inhibitors were started in 42.9% of the patients. Eight patients (28.6%) started immunosuppression therapy, within a mean time from histological diagnosis of 0.7 years (SD ±1.03). Of those, all of them were on corticosteroids, one patient was additionally under oral cyclophosphamide and another one under mofetil mycophenolate. According to the IRP-IgAN, patients were stratified in low (35.7%), intermediate (10%) and high risk (8%) of kidney disease progression (GFR decline &gt;50%) or ESKD. In a mean time of 0.53 (SD ±0.34) years of follow-up after diagnosis, 8 patients (28.6%) required renal replacement therapy, with 7 choosing hemodialysis and 1 peritoneal dialysis. Six patients lost follow-up. Three patients died a mean time of 1.2 years after diagnosis, one from immunosuppression-related adverse events. We also found an association between higher risk group and progression to ESKD (p &lt; 0.001).

Conclusion
The IRP-IgAN tool is a useful tool for prediction of kidney disease progression and the need for renal replacement therapy. The supportive care in IgAN even with antiproteinuric approach could be insufficient for patients with high and intermediate risk. The risk progression to ESKD is indeed heterogeneous, and close follow-up of these patients should be guaranteed.