ASN's Mission

To create a world without kidney diseases, the ASN Alliance for Kidney Health elevates care by educating and informing, driving breakthroughs and innovation, and advocating for policies that create transformative changes in kidney medicine throughout the world.

learn more

Contact ASN

1401 H St, NW, Ste 900, Washington, DC 20005

email@asn-online.org

202-640-4660

The Latest on X

Kidney Week

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.