Glomerular hyperfiltration in excess weight adolescents

Abstract

Background: Childhood overweight/obesity burden is on the rise worldwide. Obesity affects virtually all organs. In the kidney, glomerular hyperfiltration that manifests as elevated glomerular filtration rate is a frequent manifestation in obesity. This adaptive renal manifestation to excess metabolic demand on the kidney, in children, has been studied mainly in the severely obese and is uncertain if it is present in less severe forms of excessive weight. In addition, glomerular hyperfiltration has been reported to be associated with high levels of the indicators of cardiometabolic risk, and these latter finding are solely from adult studies.

Objective: To ascertain if glomerular hyperfiltration occurs in overweight and less severely obese children and to determine any significant relevance of some indicators of cardiometabolic risk associated with hyperfiltration.

Subjects and methods: This cross-sectional study involved 49 adolescents (28 overweight, 21 obese) and 49 normal weight adolescents. The participants were subjected to clinical examination, anthropometric measurement, laboratory investigation using standard techniques. Estimated glomerular filtration rates (eGFR) were calculated using the modified Schwartz equation. Hyperfiltration was defined as eGFR ≥140 ml/min/1.73 m².

Results: Hyperfiltration was observed in 20 (40.8%) of the overweight/obese adolescents. The prevalence of hyperfiltration among the overweight and the obese adolescent was 24.5% and 16.3%, respectively. The mean estimated glomerular filtration rate of the overweight/obese adolescents was 141.0 ± 46.2 ml/min/1.73 m², whereas that of the normal weight adolescents was 99.2 ± 17.1 ml/min/1.73 m² (P = 0.0001). A higher prevalence of hypertension was observed among the overweight/obese adolescent with glomerular hyperfiltration.

Conclusion: Glomerular hyperfiltration is not limited to morbidly obese children as the burden is also high in overweight and less severely obese adolescents.

Keywords: Adolescents; hyperfiltration; kidney; obesity; overweight.