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Abstract: TH-PO095

Thrombotic Microangiopathy Like Lesions in IgA Nephropathy: A Cohort Study

Session Information

Category: Glomerular

  • 1004 Clinical/Diagnostic Renal Pathology and Lab Medicine

Authors

  • Cai, Qingqing, Peking University First Hospital, Beijing, China
  • Shi, Sufang, Peking University First Hospital, Beijing, China
  • Lv, Jicheng, Peking University, Beijing, China
  • Zhang, Hong, Peking University First Hospital, Beijing, China
Background

Background: Thrombotic microangiopathy (TMA)-like lesion often occurs in IgA nephropathy (IgAN), but its role in disease progression is not well established, and recent Oxford MEST-C score system doesn’t include this lesion. In this study, we aim to investigate TMA-like lesions in IgAN using a prospective IgAN database cohort in Peking University.

Methods

Methods: Patients with IgAN from 2003 to 2014 who were followed at least 1 year enrolled in this study. Kidney biopsies from all participants were re-reviewed by two investigators independently blinded to the clinical data. The TMA-like lesions were graded according to criteria by El Karoui K et al (JASN 2012, 23(1):137) under light microscope(LM). The primary outcome was time to 50% decline in estimated glomerular filtration rate (eGFR), end-stage kidney disease(ESRD) or death. Multivariable Cox regression model was used to evaluate TMA-like lesions for prognosis of IgA nephropathy.

Results

Results: Among the 1052 patients, 985(93.6%) patients with pathological slides available entered the study. Overall 194 (19.7%) had TMA-like lesions. Patients with TMA-like lesions presented a higher proportion of malignant hypertension (9.8 vs 1.0%, p<0.001), a higher blood pressure (130±19 vs 122±15 mmHg, p<0.001), severer proteinuria [2.3(1.4-4.1) vs 1.4(0.7-2.8) g/d, p<0.001] and lower eGFR (58.8±26.8 vs 86.2±28.9 ml/min per 1.73 m2, p<0.001) at baseline compared to those without TMA-like lesions. After a mean follow-up of 4.1 years, 75(38.7%) patients with TMA-like lesions and 89(11.3%) with non-TMA-like lesions reached end points (p<0.001). In a multivariable Cox regression model, after taking into account clinical and pathological indicators available at the time of biopsy, TMA-like lesion was an independent risk factor for kidney progression in IgAN (HR 1.88, 95%CI:1.30-2.72, P=0.001). Moreover, the risk for kidney failure rose as the severity of TMA-like lesions increased (mild: HR 1.66, 95%CI:1.11-2.48; moderate: 2.53, 1.49-4.30; severe: 2.99, 1.27-7.04). Other renovascular sclerosis (arterial intimal fibrosis and arteriolar hyalinosis) were not risk factors of the progression of IgAN (HR: 0.84, 95%CI:0.54-1.31, p=0.441).

Conclusion

Conclusion: TMA-like lesions were frequent in IgA nephropathy and were associated with high risk of renal failure. Future pathological score of IgA nephropathy should include TMA-like lesions.

Funding

  • Government Support - Non-U.S.