Background: Focal segmental glomerulosclerosis (FSGS) is one of the most common glomerulopathies in children leading to end stage renal disease (ESRD). Different values of median renal survival have been reported among different ethnicities and races. Many factors are assumed to be responsible for ESRD in these patients. In this study, we tried to determine median renal survival (MRS) and also some clinical and histopathological features predisposing FSGS patients to ESRD in two referral hospitals in Tehran. Methods: The study involved 103 FSGS patients (61 males and 42 females) with a mean age of 7.08 ± 0.68 years. The diagnosis was made based on kidney biopsies. All kidney biopsies were studied by light and immunofluorescent microscopes. Ocular grids (counting squares) were used as the standard method to calculate the percentage of cortical interstitial fibrosis (CIF). The percentage of glomerular sclerosis was presented as renal injury score. Glomerular filtration rate (GFR)�50 ml/min was considered as renal death or the end point. Patients were followed for 1 to 15 years, until occurrence of renal death. Results: The MRS was 9.04 ± 1.8 yrs. The renal survival reached 72, 47 and 17 after 5, 10 and 15 years, respectively. Univariate analysis showed significant reverse correlation (P50, peritubular fibrosis, periglomerular fibrosis, tubular atrophy and CIF�20. However, multivariate analysis revealed only a reverse correlation between renal survival with CIF�20 and also hypertension (P<0.0001 and P<0.05, respectively). Conclusions: In our patients, FSGS showed a rapid course towards ESRD compared with patients of western countries. Perhaps some ethnic and genetic factors such as angiotensin converting enzyme genotypes (ACE-DD) can be considered as a cause of this rapid progression. Also, we carried this study only on children and adolescents which might change the MRS results
