Clinical profile and outcome of AA amyloidosis associated kidney disease in India

Background AA amyloidosis is a rare but significant cause of chronic kidney disease (CKD). We aimed to characterize the clinical profile of patients with AA amyloidosis affecting the kidneys in the Indian subcontinent. Methodology In this retrospective cohort study, we evaluated patients with kidney biopsy-confirmed AA amyloidosis and compared them with a control group of patients with diabetic kidney disease (DKD). Primary outcome was defined as a composite of ≥50% decline in estimated glomerular filtration rate (eGFR) and/or progression to end-stage kidney disease (ESKD). Results AA amyloidosis ( n = 91) accounted for 1.9% of all kidney biopsies. The median age was 45 years, and 75.8% were male. Chronic infections or inflammatory diseases were reported in 58.2%, tuberculosis being most common (35.2%). Baseline median eGFR was 66.0 mL/min/1.73 m 2 and urine protein creatinine ratio was 4.9 g/g. During median follow-up of 5.58 years, 38.6% experienced worsening kidney outcomes. Adjusted analyses showed significantly better kidney survival than DKD (0.29 (95% CI: 0.14-0.66, p = 0.002). Conclusion AA amyloidosis is an uncommon but important cause of CKD. Tuberculosis is the leading predisposing factor in Indian patients. These patients exhibit slower eGFR decline compared to DKD despite progressive proteinuria, suggesting distinct pathophysiology.