High incidence of focal segmental glomerulosclerosis in nephrotic syndromeof childhood

In recent adult literature, there have been reports of an increasing incide nce of focal segmental glomerulosclerosis (FSGS) among patients with nephro tic syndrome. To examine whether this observation is also relevant to the p ediatric population we utilized our hospital computerized database to analy ze the data on children with primary nephrotic syndrome seen first between the years 1984 and 1995. A questionnaire was also sent to all metropolitan Kansas City pediatricians to identify possible patients outside the databas e. The inclusion criteria were clinical nephrotic syndrome or proteinuria w ith a kidney biopsy. A total of 148 patients (group A) were identified; 86 of them from metropolitan Kansas City (group B). In group A the incidence o f minimal change disease (MCD) and FSGS was 52.7% [95% confidence interval (CI) 44%-60%] and 23.0% (95% CI 16-29%), respectively and in group B 54.7% (95% CI 44%-65%) and 24.5% (95% CI 15%-33%), respectively. Those numbers we re significantly different from the International Study of Kidney Disease i n Children (IS-KDC) reported incidence of 76.4% for MCD and 6.9% for FSGS. Similar to the ISKDC, in our population children over 6 years had a higher incidence of FSGS than younger children (32.8% vs. 16.7%, P=0.028). The ann ual incidence rate for nephrotic syndrome in group B was 2.2 cases/10(5) ch ildren per year, of which MCD comprised 1.22 cases/10(5) children per year and FSGS 0.5 cases/10(5) children per year. The annual incidence rates of b oth primary nephrotic syndrome (3.6) and FSGS (1.6) were significantly high er in African-Americans than Caucasians (1.8 and 0.3 cases/10(5) children p er year, respectively). Our study indicates nearly no change in the annual incidence of pediatric primary nephrotic syndrome, but a higher incidence o f FSGS with reciprocal decline in the incidence of MCD. The possibility of primary nephrotic syndrome being caused by a non-MCD entity is further rais ed among African-Americans and in children over 6 years. We conclude that o ur perception of primary nephrotic syndrome of childhood as a benign condit ion has to be carefully reexamined and a more-guarded prognostic approach a dopted in our geographic area.