Renal biopsy in patients aged 80 years and older: a single-center experience in Japan

Background: There is a paucity of data on renal biopsy in a large number of the very elderly (age >= 80 years) worldwide. Methods: Clinicopathological features in 73 patients aged >= 80 years were evaluated and compared with control groups of 172 patients aged 60 - 61 years and 128 patients aged 70 - 71 years. Results: The common indications for biopsy in the very elderly were nephrotic syndrome (NS), followed by proteinuria without NS and/or hematuria, and acute kidney injury (AKI). Histological diagnoses were considered to potentially modify treatment in 57 cases (78.1%): the most frequent diagnosis was membranous nephropathy, followed by minimal change disease, and various other diseases. There were no biopsy procedure-related serious complications. Clinical assessment of treatments was evaluated in 38 of 54 patients with AKI and/or NS. Improvement in renal dysfunction or NS was observed in 24 of 30 (80%) patients who received immunosuppressive therapy. There were statistically significant differences in the disease spectrum between the very elderly and control groups. Conclusions: This is the first report of renal biopsy findings in a relatively large number of Japanese very elderly patients. Histological observations are useful aids in estimating the prognosis and therapy selection for renal disorders, even in the very elderly.