The Spectrum of Biopsy-Proven Renal Diseases in Chinese Elderly Patients and Its Temporal Shift Over 20 Years: A Retrospective Cohort Study.

OBJECTIVE

To investigate the longitudinal pathological changes in the spectrum of biopsy-proven renal diseases among elderly patients over the past 20 years at a single center in China.

METHODS

We retrospectively enrolled patients aged ≥ 60 years who underwent renal biopsy at Beijing Hospital between January 2005 and December 2024. Patients were stratified into four 5-year periods (2005-2009, 2010-2014, 2015-2019, and 2020-2024) based on biopsy date. The frequency and distribution of biopsy-proven renal diseases across these periods were analyzed.

RESULTS

A total of 594 elderly patients were included, accounting for 29.2% of all native biopsies in our cohort. The mean age was 67.9 ± 5.7 years, with a male-to-female ratio of 1.4:1. The proportion of elderly patients undergoing renal biopsy increased significantly across the four periods (19.1%, 22.5%, 33.9%, 38.9%; χ 2 = 60.160, p < 0.01). Nephrotic syndrome (NS) was the most common indication for biopsy, although its proportion declined over time. In contrast, the proportion of biopsies performed for chronic kidney disease (CKD) increased substantially. Primary glomerular nephropathy (PGN), secondary glomerular nephropathy (SGN), and tubulointerstitial nephropathy (TIN) accounted for 54%, 39.9%, and 6.1% of all cases, respectively. The most prevalent cause of PGN was membranous nephropathy (MN), and the leading pathological types of SGN included diabetic nephropathy (DN), antineutrophil cytoplasmic antibody-associated vasculitis (AAV), and hypertensive nephropathy (HTN). Throughout the study period, the proportion of PGN decreased significantly (64.6%, 64.9%, 54.1%, 42.6%; χ 2 = 18.5, p < 0.001), driven by a decline in MN (34.1%, 39.6%, 32.6%, 23%; χ 2 = 10.015, p = 0.018). Conversely, the proportion of SGN increased markedly (29.3%, 32.4%, 39.4%, and 49.2%; χ 2 = 13.0, p = 0.004), primarily due to rising trends in DN and HTN. Notably, during the period 2020-2024, SGN surpassed PGN as the predominant form of biopsy-proven renal diseases among elderly individuals.

CONCLUSIONS

The utilization of renal biopsy in elderly patients has increased significantly over the past two decades. While NS remains the most common indication, a notable rise in biopsies for CKD has been observed. The pathological spectrum has undergone a significant shift, characterized by a dramatic decrease in PGN (especially MN) and a continuous increase in SGN (predominantly DN and HTN). The predominance shifted to SGN over PGN in biopsy-proven renal diseases among the elderly in the most recent period.