ORIGINAL ARTICLE Is focal segmental glomerulosclerosis increasing in patients with nephrotic syndrome? Fábio Fernandes Borges & Luciana Shiraichi & Marcos Paulo Hippólito da Silva & Eduardo Isaac Nishimoto & Paulo Cesar Koch Nogueira Received: 14 January 2007 / Revised: 16 April 2007 / Accepted: 17 April 2007 / Published online: 6 June 2007 # IPNA 2007 Abstract Idiopathic nephrotic syndrome in children has conventionally been associated with minimal change dis- ease. However, recent reports have conflictingly suggested that the frequency of focal segmental glomerulosclerosis (FSGS) in children might be on the increase, as has occurred in adults. The aim of the present work was to review the medical literature to ascertain whether an increase in the frequency of FSGS is occurring and, if so, to quantify such increase. We reviewed the studies comparing the frequency of FSGS in two consecutive periods over the past three decades (period 1 versus period 2). We pooled the data of the studies and then estimated FSGS frequency in two ways: (a) including in the denominator all patients with nephrotic syndrome and (b) including only patients who had under- gone kidney biopsy. Both analyses were aimed to determine the odds ratio of FSGS occurrence in the second period. Six studies fulfilled the inclusion criteria, involving 1,149 patients with nephrotic syndrome. Four studies were used to calculate FSGS frequency, including in the denominator all nephrotic patients (n =885), yielding an odds ratio of 2.22 (95% CI=1.18–4.18). The analysis combining five studies with the number of biopsies in the denominator (n =603) produced an odds ratio of 1.98 (95% CI=1.12– 3.50). These results suggest that a shift in the pathological pattern of nephrotic syndrome in children might be occurring, resulting in an increase in FSGS frequency. This hypothesis has major clinical significance due to the poorer prognosis associated with FSGS. Keywords Nephrosis, lipoid . Hyalinosis, segmental glomerular . Child . Epidemiology Introduction On the basis of data from the International Study on Kidney Diseases in Children (ISKDC) conducted in 1978, it has been accepted that minimal change disease is by far the most frequent lesion associated with idiopathic nephrotic syndrome (NS) in children and adolescents, accounting for 77% of NS cases in all biopsies performed on children, with focal segmental glomerulosclerosis (FSGS) represent- ing nearly 8–10% of cases [1]. This finding has been confirmed by previous studies, which reported rates of almost 90% for the disease due to minimal change in children with NS [2]. For many years these figures have guided professors of medicine and clinical recommendations concerning nephrotic syndrome, a clinical entity in which histopathological characteristics are important in determining the long-term prognosis [3, 4]. Although the incidence of NS has remained stable over the past three decades, recent studies have revealed significant variations in the frequency of focal segmental glomerulosclerosis (FSGS) among biopsy series worldwide, with a rise in FSGS being seen in some countries, yet not in others [4, 5]. A number of studies, largely retrospective, have shown an increase in FSGS frequency over the past 20 years across all age ranges, particularly among blacks; this has occurred in conjunction with a decline in the frequency of minimal change disease [6–13]. Nonetheless, these Pediatr Nephrol (2007) 22:1309–1313 DOI 10.1007/s00467-007-0516-0 F. F. Borges : L. Shiraichi : M. P. H. da Silva : E. I. Nishimoto Faculdade de Ciências Médicas de Santos, UNILUS, São Paulo, Brazil P. C. K. Nogueira (*) Pediatrics Department, Faculdade de Ciências Médicas de Santos, UNILUS, Rua Pageu 100 apto 11, Chácara Inglesa, 04139-000 São Paulo, Brasil e-mail: pckoch@uol.com.br