Is the Prevalence of Biopsy-Proven Glomerulopathies in Adults Changing Over Time?

Abstract

Changes over time in prevalence of glomerulopathies (GP) have been reported worldwide, but given the scarcity of data from Romania, we assessed the frequency of biopsy-proven GP over a 10-year period. This single-centre retrospective study enrolled 1 254 adults with GP on native kidneys diagnosed between 01.01.2008 - 31.12.2017, whose cases were extracted from the kidney biopsy (KB) registry of the hospital. Those with repeated KB and insufficient tissue sample or missing data were all excluded. Demographic, clinical, laboratory and histological data were analyzed and compared between subjects who underwent KB in the first and last five years (2008-2012, n=355 vs. 2013-2017, n=899). Even if nephrotic syndrome was the main reason for KB, its frequency decreased from one in two to one in three cases (p<0.001). During the second period, older subjects with lower glomerular filtration rate and proteinuria were found. Also, KB was prescribed for chronic kidney function decline three times more often (p<0.001), while acute nephritic syndrome almost doubled its prevalence among biopsies (p=0.005). IgA nephropathy and membranous nephropathy were similarly the two most frequent histological patterns in both time intervals. However, between 2013-2017, diabetic nephropathy was more commonly detected (12.3% vs. 4.8%, p<0.001), probably because more diabetics underwent KB, but also the crescentic glomerulonephritis showed higher prevalence over time (6.6% vs. 3.1%, p=0.02). Subject to the limitations of our retrospective single-centre study, its findings suggested rather a change in the diagnostic approach than an actual different GP prevalence in adults, as KB were performed in patients with more advanced age, lower kidney function and less proteinuria.

FIGURE 1.

Study flow chart (GP: glomerulopathies; IF: immunofluorescence; KB: kidney biopsy; Lab: laboratory data; N: nephropathies; pts.: patients; RRT: renal replacement therapy; TIN: tubulo-interstitial nephropathies)

TABLE 1.

General characteristics of subjects from the two studied groups at the time of kidney biopsy

TABLE 2.

The kidney biopsy indication in the two studied groups

FIGURE 2.

Variations in prevalence of glomerulopathies during the studied period (*: p<0,05; CGN: crescentic glomerulonephritis; DN: diabetic nephropathy; EPGN: diffuse endocapillary proliferative glomerulonephritis; FSGS: focal and segmental glomerulosclerosis; HGP: hereditary glomerulopathies; IgAN: IgA nephropathy; LN: lupus nephritis; MCD: minimal change disease; MN: membranous nephropathy; MPGN: membranoproliferative glomerulonephritis; Others = monoclonal immunoglobulin deposition disease, fibrillary glomerulonephritis, thrombotic microangiopathy; RA: renal amyloidosis).