Renal Biopsy in Very Elderly Patients: Data from the Spanish Registry of Glomerulonephritis

BACKGROUND: Studies on renal histology results in very elderly patients are extremely rare. METHODS: We analyzed histology and clinical findings in patients aged over 85 years undergoing renal biopsy and whose data were included in the Spanish Registry of Glomerulonephritis between 1994 and 2009. RESULTS: A total of 17,680 native kidney biopsies were taken: 71 (0.4%) were from patients aged over 85 years. Acute kidney injury (AKI) was the main indication for biopsy (47%), followed by nephrotic syndrome (32%). Amyloidosis was the most common histological diagnosis (16.9%), followed by crescentic glomerulonephritis type 3 associated with systemic vasculitis (14.1%). When histological findings were correlated with clinical syndromes, we found that amyloidosis was the leading cause of AKI (18.8%), and also the main determinant of nephrotic syndrome, with the same frequency as membranous nephropathy (22%). Crescentic glomerulonephritis type 3 associated with vasculitis was related to a greater diversity of clinical syndromes, especially chronic kidney disease (40%) and AKI (40%). CONCLUSIONS: Renal biopsy in the very elderly provides us with useful information, despite the advanced age of the patients. AKI and nephrotic syndrome are the main indication for renal biopsy in this subgroup of patients, and amyloidosis is the most frequent histological pattern associated with both syndromes.