The spectrum of biopsy-proven glomerular diseases in a tertiary Hospital in Southern Brazil.

BACKGROUND: The prevalence and distribution of glomerular diseases differ among countries, and the indication to perform a kidney biopsy varies among centres. In this study, we assessed the prevalence of primary and secondary glomerulopathies based on histological diagnoses, and the correlation between glomerulopathies and demographic and clinical data was evaluated. METHODS: In this study, 1051 kidney biopsies were retrospectively reviewed between 2000 and 2018. Patient demographic, clinical and laboratory data were assessed. The prevalence of primary glomerulonephritis (PG) and secondary glomerulopathies (SG), as well as tubulointerstitial diseases (TIDs), hereditary nephropathies (HNs) and other diagnoses, were determined. The frequency of primary and secondary glomerulopathies was evaluated by age group, and the temporal variation in frequencies across three time periods (2000-2005, 2006-2011, and 2012-2018) was reported. RESULTS: The prevalence of SG predominated (52.4%), followed by PG (29.6%), other diagnoses (10.7%), TID (6.6%) and HN (1.1%). Among the primary forms of glomerular disease, focal segmental glomerulosclerosis (FSGS) was the most common (37.3%), followed by IgA nephropathy (IgAN, 24.4%), membranous nephropathy (MN, 18.6%) and minimal change disease (MCD, 8.4%). Lupus nephritis (LN, 41.1%) was most common in patients with SG, followed by diabetic kidney disease (DKD, 17.8%), systemic vasculitis (SV, 10.2%) and secondary FSGS (2nd FSGS, 10%). Nephrotic syndrome was the most common clinical presentation in patients with PG and also in patients with DRD and 2nd FSGS, whereas in patients with IgAN and SV, nephritic syndrome was the main presentation. For the age group between 18 and 50 years, LN, FSGS and IgAN predominated; for patients aged between 51 and 65 years, the proportion of DKD and 2nd FSGS increased, and SV was more common in patients > 65 years. The temporal variation in PG across the three time periods showed a statistically significant increase in IgAN (p = 0.001) and a reduction in FSGS over time (p < 0.001). In SG, there was a reduction in LN (p = 0.027) and an increase in DKD (p < 0.001) over time, with a tendency for 2nd FSGS to decrease over time (p = 0.053). CONCLUSIONS: In the studied kidney biopsy registry, FSGS and IgAN were the most prevalent diagnoses in patients with PG, and LN and DKD were the most prevalent in patients with SG. Nephrotic syndrome was the major indication for biopsy. When comparing the temporal variation in glomerulopathies, there was a reduction in FSGS and an increase in IgAN in patients with PGs over time, and for patients with SGs, there was a reduction in LN with an increase in cases of DKD over time.

Glomerulopatias prevalentes na Bahia, um estudo baseado em biópsias / Glomerulopathies prevalent in Bahia, a study based on biopsies

A prevalência de doenças renais em pacientes encaminhados aos Serviços de Nefrologia em hospitais terciários em Salvador, Brasil, foi avaliada através de exames histopatológicos. Analisamos, retrospectivamente, 228 biópsias renais realizadas entre janeiro de 2003 a junho de 2006. Destes, 159 preencheram os critérios para inclusão no estudo. Foram examinados por microscopia óptica, imunofluorescência (arquivos de imagens digitais) e, quando necessário, por microscopia eletrônica. Compilamos informações sobre gênero, idade, etnicidade, a síndrome clínica e a duração da doença renal. A revisão histológica das biópsias foi realizada em três etapas. Inicialmente, por dois patologistas, simultaneamente, usando um microscópio multiobservador. Em seguida, os diagnósticos foram revistos por um observador independente. Ao final, os casos sem unanimidade no diagnóstico foram revistos pelos três patologistas em conjunto, para se chegar a um diagnóstico consensual. A nefropatia primária mais freqüente foi a esclerose glomerular focal e segmentar, somando 27% dos casos. Outros 15% foram identificados como parte do espectro alteração mínima-esclerose segmentar focal desta doença. Encontramos glomerulopatia membranosa em 9%, glomerulonefrite membranoproliferativa em 7%, e nefropatia por imunoglobulina A em 5%. A nefropatia secundaria mais freqüente foi a nefrite lúpica, constituindo 14% do total. Concordância entre observadores no diagnóstico das nefropatias foi de 93%, com kapa 0,919, DP 0,03 e p<0,01. Este é o primeiro estudo descritivo da prevalência das glomerulopatias em Salvador, Brasil, com utilização de imunofluorescência e microscopia eletrônica. As glomerulopatias primárias e secundárias mais freqüentes foram glomeruloesclerose focal e segmentar e nefrite lúpica. Estes achados representam uma alteração da prevalência das glomerulopatias na Bahia, antes mais influenciada pela infestação por Schistosoma mansoni.

The prevalence of renal diseases in patients referred to tertiary hospitals in Salvador, Brazil was evaluated by histopathological examination. 228 biopsies of native kidneys, performed from January, 2003 through June, 2006, were retrospectively analyzed; 159 of these fulfilled the criteria for inclusion in this study. They were reviewed by light microscopy, immunofluorescence (digital image archives) and, whenever necessary, by electron microscopy. Gender, age ethnicity, duration of the renal disease and clinical syndrome were studied. Histological revision of the biopsies was performed in three rounds: 1st, by two pathologists using a multiobserver microscopy; 2nd, an independent revision by an external examiner and 3rd, the cases given discrepant diagnosis were revised by all the observers working together. Focal and segmental glomerular sclerosis was the most frequent primary nephropathy, encountered in 27% of the cases. Another 15% were identified as part of the minimal change - focal segmental sclerosis spectrum of disease. Membranous glomerulopathy comprised 9%, membranoproliferative glomerulonephritis 7%, and immunoglobulin A nephropathy, 5% of the total. Lupus nephritis was the most common secondary nephropathy, corresponding to 14% of the cases. Interobserver concordance in the diagnosis of nephropathies was 93%, with Kappa 0.919, standard error 0.03 and P < 0.01. This is the first descriptive study of the prevalence of glomerulopathies in renal biopsies in Salvador, Brazil, using all the recourses of immunofluorescence and electron microscopy. Focal and segmental glomerulosclerosis and systemic lupus nephritis were identified as the most frequent primary and secondary glomerulopathies, respectively. This data may represent a shift in the patter of distribution of glomerulopaties in Bahia, formerly influenced by S. mansoni infection.