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Abstract: TH-PO1011

Impact of Histological Findings of Thrombotic Microangiopathy on the Prognosis of Patients with IgA Nephropathy

Session Information

Category: Glomerular Diseases

  • 1203 Glomerular Diseases: Clinical, Outcomes, and Trials

Authors

  • Souza, Rafael A. S., University of São Paulo (USP), São Paulo, São Paulo, Brazil
  • Torres, Fabio M., University of São Paulo (USP), São Paulo, São Paulo, Brazil
  • Reis, Fábio A., University of São Paulo (USP), São Paulo, São Paulo, Brazil
  • Pinheiro, Rafaela B., University of São Paulo (USP), São Paulo, São Paulo, Brazil
  • Smolentzov, Igor, University of São Paulo (USP), São Paulo, São Paulo, Brazil
  • Santa Catharina, Guilherme P., University of São Paulo (USP), São Paulo, São Paulo, Brazil
  • Cavalcante, Livia Barreira, University of São Paulo (USP), São Paulo, São Paulo, Brazil
  • Neves, Precil D., University of São Paulo (USP), São Paulo, São Paulo, Brazil
  • Dias, Cristiane B., University of São Paulo (USP), São Paulo, São Paulo, Brazil
  • Malheiros, Denise M., University of São Paulo (USP), São Paulo, São Paulo, Brazil
  • Yu, Luis, University of São Paulo (USP), São Paulo, São Paulo, Brazil
  • Woronik, Viktoria, University of São Paulo (USP), São Paulo, São Paulo, Brazil
  • Jorge, Lectícia, University of São Paulo (USP), São Paulo, São Paulo, Brazil
Background

IgA Nephropathy (IgAN) is the most common primary glomerulopathy in the world. The Oxford classification considers glomerular and tubulo-interstitial changes as prognostic markers of the disease, however, vascular alterations such as Thrombotic Microangiopathy (TMA) were not included in this classification. The aim of this study is to evaluate the impact of TMA on the prognosis of IgAN patients.

Methods

This is a retrospective cohort study of histological findings of native kidney biopsies between 1999 and 2018 in an academic center. The primary outcome was the TMA impact on loss of renal function and progression to ESRD.

Results

The cohort included 118 patients, 54% women, 73% caucasian, mean age of 33 years (25; 43), followed-up of 65 months (27; 115), with similiar treatment regimens. At the moment of diagnosis, 68% patientes presented with hypertension, 90% hematuria, 12.5% Complement consumption, mean SCr 1.45mg/dL (0.99; 2.6), eGFR 48.8 mL/min/1.73m2 (27.5; 78), Albumin: 3.4 g/dL (2.9, 3.8), 24h proteinuria 2.01g (1.1, 3.7). Distribution according to Oxford classification: 76% M1, 36% E1, 70% S1, 38% T1 or T2, 29% C1 or C2.
Patients with TMA had more hypertension (100 vs 61%, p <0.0001), hematuria (100 vs 87.6%, p = 0.0001), higher SCr (3.8 vs 1.38 mg/dL, p = 0.0001), lower eGFR (18 vs 60 mL/min/1.73m2, p = 0.0001), Complement consumption (28.5 vs 10.4%, p = 0.003), lower Hemoglobin (10.6 vs 12.7g / dL, p <0.001) and Platelets (207 vs 267 x103, p = 0.001) when compared to non-TMA patientes. Comparing the two groups, the only difference at the Oxford classification found was more patients with E1 at TMA group (68 vs 32%, p = 0.002). In the primary outcome analysis, patients with TMA presented faster loss of renal function (ΔeGFR / year: -6.8 vs -1.65 mL/min/1.73m2 , p=0.01), more frequent and faster evolution to ESRD (71.4 vs 21.6%, p <0.0001; 3 vs 16 months, p = 0.003 respectively).

Conclusion

Histological findings of TMA at IgAN implies on worse outcomes. Our findings suggest that vessel assessment may have an impact on prognosis of patients with IgAN and the presence of vascular lesions should be contemplated in the Oxford Classification.