Relationship Between Severity of Renal Amyloid Deposition and Clinical Outcomes in Non-AA Amyloidosis

Objective: Renal involvement is a common manifestation of systemic amyloidosis. Amyloid load can be predicted by histopathological grading of amyloid deposits in renal biopsy specimens. This study aimed to determine the relationship of renal amyloid deposition grade with clinical manifestations and outcomes in patients with biopsy-proven renal non-AA amyloidosis. Methods: This retrospective cohort study included 74 subjects with renal non-AA amyloidosis (52 light chain amyloidosis and 22 unclassified amyloidosis). Baseline characteristics and follow-up data were recorded. Pattern and quantity of amyloid deposition in glomeruli, interstitium, vessels, and tubulointerstitial changes were scored. Renal Amyloid Prognostic Score was obtained by addition of all scores and divided into 3 grades (Renal Amyloid Prognostic Score grades I, II, III). Results: In light chain amyloidosis group, the median follow-up was 11 (4-45) months. The baseline estimated glomerular filtration rate was significantly lower among patients with Renal Amyloid Prognostic Score grade III. Death-censored Renal survival was significantly lower among patients with Renal Amyloid Prognostic Score grade III. Renal Amyloid Prognostic Score grade III was a significant predictor of lower renal survival. Patient survival was not significantly different according to Renal Amyloid Prognostic Score grade. Receiving autologous stem cell transplantation treatment was associated with better patient survival. The type of amyloid could not be determined in 22 patients. In this group, baseline estimated glomerular filtration rate was significantly lower in patients with Renal Amyloid Prognostic Score grade III. Conclusions: In patients with light chain amyloidosis, baseline renal function is associated with Renal Amyloid Prognostic Score grade. Renal survival is significantly lower in patients with the highest Renal Amyloid Prognostic Score grade. However, patient survival is not significantly different according to Renal Amyloid Prognostic Score grade.

Automated summary

This study found a relationship between the grading of amyloid deposition and renal function and prognosis in patients with non-AA renal amyloidosis. However, the grading did not significantly affect patient survival.