Kidney Week

Abstract: SA-PO758

Clinical Phenotype Identifies Individuals with ANCA-Associated Vasculitis Who Do Not Require Kidney Biopsies for Diagnosis of Kidney Involvement

Session Information

• ANCA-Associated Vasculitis, Anti-GBM Disease, and Other RPGN
  October 26, 2024 | Location: Exhibit Hall, Convention Center
  Abstract Time: 10:00 AM - 12:00 PM

Category: Glomerular Diseases

• 1402 Glomerular Diseases: Clinical, Outcomes, and Therapeutics

Authors

• Al Jurdi, Ayman, Massachusetts General Hospital, Boston, Massachusetts, United States

Ayman Al Jurdi, MD, FASN

• El Mouhayyar, Christopher, Massachusetts General Hospital, Boston, Massachusetts, United States

Christopher El Mouhayyar, MD

• Sauvage, Gabriel, Massachusetts General Hospital, Boston, Massachusetts, United States

Gabriel Sauvage

• Jeyabalan, Anushya, Massachusetts General Hospital, Boston, Massachusetts, United States

Anushya Jeyabalan, MD

• Efe, Orhan, Massachusetts General Hospital, Boston, Massachusetts, United States

Orhan Efe, MD

• Seethapathy, Harish Shanthanu, Massachusetts General Hospital, Boston, Massachusetts, United States

Harish Shanthanu Seethapathy, MD, MBBS

• Cosgrove, Katherine M., Massachusetts General Hospital, Boston, Massachusetts, United States

Katherine M. Cosgrove, RN

• Laliberte, Karen A., Massachusetts General Hospital, Boston, Massachusetts, United States

Karen A. Laliberte, RN

• Niles, John, Massachusetts General Hospital, Boston, Massachusetts, United States

John Niles, MD

Background

Kidney involvement is common in ANCA-associated vasculitis (AAV). The most common finding on kidney biopsy in AAV is crescentic glomerulonephritis (GN). Guidelines recommend kidney biopsy in individuals with AAV and kidney abnormalities to confirm kidney involvement. Kidney biopsies are associated with a risk of bleeding and may delay treatment for active AAV. Therefore, identification of characteristics associated with a high likelihood of finding crescentic GN on biopsy can avoid the need for kidney biopsy in these individuals and its associated risks and costs.

Methods

We conducted a single-center retrospective cohort study of all individuals with a positive ANCA test and a kidney biopsy between 2000 and 2023 at the Vasculitis and Glomerulonephritis Center at Massachusetts General Hospital. The positive predictive value (PPV) for finding crescentic GN on biopsy based on various clinical findings was evaluated.

Results

142 individuals met the study's inclusion criteria. The median age was 64 and 55% were female. The median serum creatinine was 2.49 mg/dL, and 89% had microscopic hematuria. 73%, 24%, and 3% were positive for antibodies to myeloperoxidase, proteinase 3, or both, respectively. Crescentic GN was found in 85% of biopsies (Fig. 1A). 100% of individuals with ANCA positivity and rapidly progressive GN (defined as ≥50% eGFR loss in ≤6 months, n = 45) had crescentic GN on biopsy. Over 93% of individuals with ANCA positivity, microscopic hematuria, and ≥1 extra-renal system involvement had crescentic GN on biopsy (Fig. 1B).

Conclusion

The rate of kidney function decline, microscopic hematuria, and extra-renal symptoms identify individuals with AAV who do not require kidney biopsy to establish kidney involvement.

Figure 1. Diagnostic value of ANCA testing for kidney involvement by vasculitis. (A) Kidney biopsy results. (B) Positive predictive value of different clinical presentations.

Funding

• Veterans Affairs Support