Renal AA amyloidosis associated with inflammatory bowel disease

Renal AA amyloidosis is a rare but severe complication of inflammatory bowel disease (IBD), associated with significant renal morbidity and poor prognosis. Data remain limited, particularly in underrepresented regions such as North Africa. This study aimed to describe its clinical features, management, and renal outcomes in a multicenter cohort.

We conducted a retrospective multicenter study including patients with IBD-associated renal AA amyloidosis from two tertiary nephrology centers in Tunisia between 1990 and 2022. Continuous variables are expressed as median, interquartile range (IQR) and range.

Seventeen patients were included (14 Crohn's disease, 3 ulcerative colitis). The median age was 37 years [IQR: 29.5-47; range: 19-68], with a male predominance. The median interval between IBD diagnosis and renal involvement was 3 years. All patients had heavy proteinuria, with nephrotic syndrome in 15 cases. Median serum albumin was 20.1 g/L [IQR: 9.4-23.4], and impaired renal function was observed in eight patients. Diagnosis was established by minor salivary gland biopsy (n = 10) or renal biopsy (n = 7). Treatment strategies were heterogeneous: nine patients continued prior IBD therapy, while others received colchicine (n = 5), corticosteroids (n = 2), or anti-TNF-α therapy (n = 1). Renal outcomes were poor: one patient required dialysis at baseline, and eight progressed to end-stage kidney disease over a median of 19 months [IQR: 7-37].

Renal AA amyloidosis is a severe complication of IBD with poor renal prognosis. Early detection and effective control of chronic inflammation are essential to improve outcomes.