Current distribution pattern of biopsy-proven glomerular disease in Salvador, Brazil, 40 years after an initial assessment / Padrão de distribuição atual da doença glomerular documentada por biópsia em Salvador, Brasil, 40 anos após a avaliação inicial

Abstract Introduction: A report on the prevalence of glomerular disease diagnosed via renal biopsy in Salvador, BA, Brazil was published in 1973 and showed a predominance of membranoproliferative glomerulonephritis, which was frequently associated with hepatosplenic schistosomiasis. Objective: In this study, we investigate the potential changes in the distribution of glomerular diseases after a period of important epidemiological transition in Brazil. Methods: Pathology reports of all patients subjected to kidney biopsy from 2003 to 2015 in a referral nephrology service were reviewed. Clinical, laboratorial and pathological diagnoses were collected for analysis. Histological slides of the biopsies performed between 2003 and 2006 were reviewed to examine the accuracy of the estimates based on the pathology reports. Results: Among the biopsies performed during the time period, 1,312 met the inclusion criteria for the study. Focal and segmental glomerulosclerosis was the most prevalent diagnosis, followed by lupus nephritis. However, a trend toward a decrease in the prevalence of focal and segmental glomerulosclerosis was detected (p < 0.05), and an increase in lupus (p < 0.0001) and membranous glomerulonephritis (p < 0.005) was observed. Conclusion: The data presented herein suggest the occurrence of changes in the distribution of nephrological diseases in Salvador, Brazil. The disease that was most prevalent shifted from membranoproliferative glomerulonephritis to focal and segmental glomerulosclerosis from 1975 to 2006 and from focal and segmental glomerulosclerosis to lupus nephritis from 2006 to 2015.

Resumo Introdução: um relatório sobre a prevalência de glomerulopatia diagnosticada por biópsia renal em Salvador foi publicado em 1973, demonstrando o predomínio de glomerulonefrite membranoproliferativa, frequentemente associada a esquistossomose hepatoesplênica. Objetivo: no presente estudo, investigamos as possíveis mudanças na distribuição das glomerulopatias após um período de importantes transições epidemiológicas no Brasil. Métodos: foram revisados todos os relatos de pacientes submetidos a biópsia renal de 2003 a 2015 em um serviço de referência em nefrologia. Diagnósticos clínicos, laboratoriais e patológicos foram colhidos para análise. Lâminas histológicas das biópsias executadas entre 2003 e 2006 foram revisadas para avaliar a precisão das estimativas baseadas nos laudos anatomopatológicos. Resultados: entre as biópsias realizadas durante o período em questão, 1.312 satisfizeram os critérios de inclusão do estudo. Glomeruloesclerose segmentar e focal foi o diagnóstico mais prevalente, seguido de nefrite lúpica. Entretanto, foi detectada tendência de queda na prevalência da glomeruloesclerose segmentar e focal (p < 0,05) e de elevação nos casos de lúpus (p < 0,0001) e glomerulonefrite membranosa (p < 0,005). Conclusão: os dados apresentados neste estudo sugerem a ocorrência de mudanças na distribuição das doenças nefrológicas em Salvador. A doença mais prevalente passou de glomerulonefrite membranoproliferativa para glomeruloesclerose segmentar e focal de 1975 a 2006 e de glomeruloesclerose segmentar e focal para nefrite lúpica de 2006 a 2015.

Schistosomal glomerulopathy and changes in the distribution of histological patterns of glomerular diseases in Bahia, Brazil

Distinct patterns of glomerular lesions, including membranoproliferative glomerulonephritis and focal segmental glomerulosclerosis, are associated with infection by Schistosoma mansoni or Schistosoma japonicum. Evidence suggests that immune complex deposition is the main mechanism underlying the different forms of schistosomal glomerulonephritis and that immune complex deposition may be intensified by portal hypertension. The relationship between focal segmental glomerulosclerosis and schistosomiasis remains poorly understood. A clinicopathologic classification of schistosomal glomerulopathies was proposed in 1992 by the African Association of Nephrology. In Brazil, mass treatment with oral medications has led to a decrease in the occurrence of schistosomal glomerulopathy. In a survey of renal biopsies performed in Salvador, Brazil, from 2003-2009, only 24 (4 percent) patients were identified as positive for S. mansoni infection. Among these patients, only one had the hepatosplenic form of the disease. Focal segmental glomerulosclerosis was found in seven patients and membranoproliferative glomerulonephritis was found in four patients. Although retrospective studies on the prevalence of renal diseases based on kidney biopsies may be influenced by many patient selection biases, a change in the distribution of glomerulopathies associated with nephrotic syndrome was observed along with a decline in the occurrence of severe forms of schistosomiasis.

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.