Pediatric nephrology patients are overweight: 20 years' experience in a single Canadian tertiary pediatric nephrology clinic

Background Obesity is an independent risk factor for chronic kidney disease (CKD). We compared the body composition of pediatric nephrology patients with that of the general child population over 2 decades. Methods About 4,959 patients above 2 years of age (mean: 9.6 ± 4.5) were referred to a tertiary pediatric nephrology clinic from 1985 to 2006. In 3,422 patients (69.0% with the same mean age) there were sufficient data to analyze body composition, expressed as body mass index (BMI) Z-score and calculated on the basis of normal data taken from the National (USA) Center for Health Statistics (2000). Results Hematuria (21.68%), recurrent urinary tract infections (16.09%), proteinuria (13.95%) and hypertension (8.27%) were the most common referral diagnoses. Mean BMI Z-score of the pediatric nephrology patients increased significantly from 0.29 ± 1.07 during the years 1985–1991 to 0.44 ± 1.27 in 1992–1999 and 0.87 ± 1.70 in 2000–2006 (P < 0.0001, ANOVA). Whereas the rate of the increase in BMI Z-score was not statistically different from that seen in the normal population, the young nephrology patients had over the entire time consistently significantly higher BMI Z-scores (average +0.72) than the comparable normal USA data. Several disease groups with potential for development of CKD had higher BMI Z-scores than found in the age- and sex-adjusted control data. Conclusions The increased rate of obesity in our studied population suggests that pediatric nephrology patients are at even greater risk for developing CKD later in life than could be predicted from their renal disease only. We recommend therapeutic intervention to address this potentially modifiable risk factor.