Kidney Biopsy in 613 Elderly Brazilian Patients: Clinicopathological Correlations

According to the Brazilian Dialysis Survey 2022 glomerular diseases are among the three main causes of chronic kidney disease in the elderly. The distribution and presentation of such kidney diseases specifically in elderly need additional and more recent data in Brazil.

Retrospective analysis of 613 native kidney biopsies from patients aged 60 years and above, in a single center, of the five regions of Brazil, performed from 2015 to 2020.

Most patients were males with a mean age of 67.5 years. Nephrotic syndrome (NS) was the main clinical indication (52.4%), followed by asymptomatic urinary abnormalities (AUA, 21.4%), rapidly progressive glomerulonephritis (RPGN, 10.1%), and acute renal failure (ARF, 6.1%). In the group aged 80 years and over, indications were significantly increased due to acute conditions (ARF and RPGN) compared to other groups. Membranous nephropathy (MN) was the most common histopathological diagnosis, followed by pauci-immune glomerulonephritis (PIGN, 12.7%) and diabetic nephropathy (DN, 10.3%). DN was more frequent in the younger elderly, amyloidosis between 70 and 79 years old, and PIGN in those aged 80 or older. Younger men had higher frequencies of IgA nephropathy (IgAN) and focal segmental glomerulosclerosis (FSGS); younger women had more PIGN, amyloidosis, and minimal change disease (MCD); 80 or more women had more PIGN and chronic glomerulonephritis. The clinical presentation of NS was mainly associated with the histopathological findings of MN and MCD. AUA was more associated with MN and IgAN.

In this study, the NS was the most frequent clinical presentation, and the most common histopathological finding was MN. We observed differences in glomerular disease frequencies between genders and age-groups in the elderly. Considering our findings, we emphasize the importance of kidney biopsy in this age-group due to the potential for improvement with specific treatments.