Kidney Week

Abstract: SA-PO839

Clinicopathological Profile and Outcomes of Kidney Amyloidosis: A Single-Centre Retrospective Biopsy Registry Cohort Study

Session Information

• C3G, TMA, MGRS, Amyloidosis, and More
  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

• John, Elenjickal Elias, Christian Medical College Vellore, Vellore, Tamil Nadu, India

Elenjickal Elias John, MD

• Alam, Rizwan, Christian Medical College Vellore, Vellore, Tamil Nadu, India

Rizwan Alam, MD, MBBS

• David, Vinoi George, Christian Medical College Vellore, Vellore, Tamil Nadu, India

Vinoi George David, MD

• Varughese, Santosh, Christian Medical College Vellore, Vellore, Tamil Nadu, India

Santosh Varughese, MD

• Alexander, Suceena, Christian Medical College Vellore, Vellore, Tamil Nadu, India

Suceena Alexander, MD, MBBS, PhD, FASN

Background

Kidney is the most common organ involved in systemic amyloidosis. The two most common types of amyloidosis affecting the kidneys are immunoglobulin (Ig)-derived and AA amyloidosis. Although classified under the same bracket of amyloidosis, each of these subtypes vary in their presentation, histology and outcomes which is not well defined.

Methods

This was an observational retrospective biopsy registry cohort study. done at a single centre in South East Asia. In total, 260 consecutive patients of amyloidosis who underwent kidney biopsy between January 2005 and December 2022 were included in this study.

Results

The mean age of the cohort was 52.5 ± 11.4 years and 67.3% were males. The most common histological type of amyloidosis was Ig amyloidosis (73.1%) followed by AA (14.6%) and undifferentiated amyloidosis (11.5%). Ig amyloidosis included 186 patients of AL amyloidosis and 4 patients of AHL amyloidosis. Extra-kidney involvement was seen in 22.7% patients. Patients with AA amyloidosis were younger, had a lower baseline estimated glomerular filtration rate (eGFR) and none of the patients had cardiovascular involvement. Patients with Ig amyloidosis were older, and almost half of the patients presented with nephrotic syndrome. Histologically, half of the patients had both glomerular and vascular deposits. Vascular and interstitial involvement was less commonly seen in undifferentiated amyloidosis. Majority (82%) of patients with Ig amyloidosis had lambda monoclonal light chain deposits. CyBorD was the most used chemotherapeutic regimen in Ig amyloidosis (38%). Of the 121 patients with follow-up >3months, 21 (17%) patients progressed to kidney failure over a median period of 11 (IQR, 8.5-29.5 months). The predictors of kidney failure were baseline eGFR < 30 ml/min, extensive glomerular amyloid deposits, moderate to severe IFTA and persistent proteinuria at follow-up. On Cox proportional hazard model, the only significant predictor was baseline eGFR < 30 ml/min [ HR 4.37 (95% CI 1.01-18.88)]. Patients of Ig amyloidosis who did not attain VGPR were more likely to have persistent proteinuria at follow up (73% vs. 42%).

Conclusion

Clinicopathological presentation and outcomes differ based on the type of amyloidosis. Attainment of VGPR is associated with better kidney outcomes in Ig amyloidosis.