Epidemiological study of childhood nephrotic syndrome in children in Australia

Elisabeth Hodson, Narelle Willis, Jeffrey Fletcher, Jonathan Craig

Nephrotic syndrome is a condition in which large quantities of protein leak from the circulation into the urine through the kidneys’ filtering units (glomeruli). Though the majority of children with nephrotic syndrome respond to corticosteroid treatment, 70% will have a relapsing course. Children with congenital nephrotic syndrome develop kidney failure. All share a significant risk of complications of the nephrotic syndrome - life-threatening bacterial infection and thrombosis - and those treated with steroids frequently suffer complications such as growth failure, obesity and high blood pressure. The Australian Paediatric Surveillance Unit (APSU) has a well established system for the prospective identification of all children with uncommon conditions achieving a 95% report rate. The current study through the APSU aims to determine the incidence of idiopathic and congenital nephrotic syndrome in children in Australia, to describe its distribution in relation to age, sex, socio-economic status, geography and ethnicity, to determine complication rates and to describe the therapeutic regimens used.

During the three year data collection period from July 1998 to June 2001, APSU cards were sent monthly to all paediatricians in Australia. Paediatricians were given information on case definition and reporting instructions at the beginning of the survey and were asked to report new cases of nephrotic syndrome. Following notification an initial questionnaire was sent to the paediatrician requesting demographic information and details of initial management. A follow up questionnaire was sent after one year asking for information on response to treatment and complications. Incidences (mean and 95% confidence intervals) are determined using population data from the Australian Bureau of Statistics.

Preliminary results are shown in the table below. The incidence of childhood nephrotic syndrome in Australia is 1.15 per 100,000 children below the age of 15 years. This is lower that the incidence reported in studies from USA and UK. Further analysis is in progress.