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Glomerular diseases are the main cause of end-stage chronic kidney disease in the world. Its prevalence varies between regions, with no studies in Chile that characterize them. Our main objective is to evaluate the prevalence of glomerular diseases in the country, analyzing histological studies in a collaborative multicenter effort.
We designed a retrospective, descriptive, multicenter study with 18 participating public and private centers. Patients over 15 years of age who underwent percutaneous renal biopsy of native kidney between 1999 and 2022 were considered. Demographic data, clinical syndrome that led to performing the renal biopsy, laboratory tests, and histological diagnosis were recorded. All biopsies were analyzed by renal pathologists and cases with insufficient histological sample for analysis were excluded. Diagnoses were classified as primary glomerulopathies, secondary glomerulopathies, hereditary glomerular diseases, tubulointerstitial nephropathies and other indeterminate or low frequency nephropathies. Analyzes were performed with summary measures and the national frequency of glomerulopathies was compared with reported international series, using X2. A value of p <0.01 was considered statistical significance. This study was approved by the Ethics Committee.
4217 patients undergoing biopsy were analyzed, excluding 86 cases with insufficient histological sample for diagnosis (n=4131). The median age was 46 years and 56.9% were female. The most frequent clinical syndromes that motivated renal biopsy were nephrotic syndrome, alterations in urinalysis, and rapidly progressive renal failure (42.8%; 26.7; and 11.5% respectively). Of the total biopsies, 47.8% corresponded to primary glomerulopathies; 43.5% to secondary glomerulopathies; 1% to hereditary glomerular disorders and 4.5% to tubulointerstitial diseases. The most prevalent primary glomerulopathies in their group were IgA nephropathy (34.6%); membranous nephropathy (26%); and focal and segmental glomerulosclerosis (14.1%); while the most frequently diagnosed secondary diseases were lupus nephropathy (42.8%); pauciimmune glomerulonephritis (18.4%) and diabetic nephropathy (10.1%). When comparing the frequency with published data from North America and Europe, a lower frequency of focal and segmental glomerulosclerosis and diabetic nephropathy is observed (p<0.01); and a higher prevalence of lupus nephropathy and pauci-immune GN (p<0.01).
The most prevalent glomerular diseases in biopsy studies were lupus nephropathy, IgA nephropathy, membranous nephropathy, focal and segmental glomerulosclerosis, and pauci-immune glomerulonephritis. In comparison to international reports, a high proportion of lupus nephropathy and membranous nephropathy is striking, which should motivate studies of probable linked causal factors in the population analyzed.