Renal AA Amyloidosis Associated with Inflammatory Bowel Disease

Abstract Introduction: Renal amyloidosis related to serum amyloid A (AA amyloidosis) is a rare but severe complication of inflammatory bowel disease (IBD), associated with significant renal morbidity; this study aimed to describe its clinical features, management, and renal outcomes in a multicenter cohort. Methods: We conducted a retrospective study across two tertiary referral nephrology centers including patients with IBD and renal AA amyloidosis. Data were collected from 1990 to 2022 in the nephrology department of Charles Nicolle hospital Tunis and from 2008 to 2022 in the nephrology department of Sahloul hospital Sousse. Results: Seventeen patients with IBD : 14 with Crohn’s disease and 3 with ulcerative colitis were included. The median age at diagnosis was 37 years [range: 19–68], with a male predominance. The median interval between IBD diagnosis and detection of renal involvement was 3 years. All patients had heavy proteinuria (>3 g/24 h), with nephrotic syndrome in 15 patients. Reduced kidney function was observed in eight patients. Diagnosis was established by minor salivary gland biopsy in 10 patients and by renal biopsy in seven. Nine patients continued previous IBD therapy, five received colchicine, two systemic corticosteroids, and one anti–TNF-α therapy. Renal outcomes were poor. One patient was dialysis-dependent at baseline, and eight patients progressed to end-stage kidney disease requiring dialysis over a median time of 19 months. Conclusion: Renal AA amyloidosis represents a serious complication of IBD with poor renal prognosis. Early diagnosis and optimal control of intestinal inflammation are essential to prevent irreversible kidney damage.