Pilot Study Looks for Link Between Obesity and Cardiovascular Disease in Pediatric Chronic Kidney Disease

Our division was recently awarded the Pediatric Center of Excellence in Nephrology (PCEN) to promote clinical trials in children with kidney disease. Using the Clinical Phenotyping Core of this P50 grant, Amy Kogon, MD, MPH, an attending nephrologist and junior investigator at Children's Hospital of Philadelphia (CHOP), is leading a pilot study to compare the energy balance, body composition, eating behaviors, and cardiovascular disease (CVD) markers of children with chronic kidney disease (CKD) to controls.

In children with CKD, CVD is one of the leading causes of death. Children with CKD face unique challenges, including polypharmacy, altered biochemical metabolism, and dietary and activity restrictions that likely promote obesity and pose distinct obstacles to treatment and prevention.

For the study, Kogon consulted with co-lead of the P50 Computable Phenotypic Core, Babette Zemel, PhD, Associate Program Director of CHOP’s Clinical and Translational Research Center and Director of the hospital’s Bionutrition Core Laboratory, who also serves as her research mentor. Zemel is a body composition expert who has found that children with CKD demonstrate altered body composition when compared to healthy children.

Kogon’s central hypothesis is that pediatric CKD alters body composition in a way that affects cardiovascular intermediate end points, such as heart structure and function and high blood pressure, and increases cardiovascular risk. This cross-sectional study of 53 children with CKD stages III-V and a comparable group of 53 unaffected children (controls) will assess alterations in energy balance, body composition, and eating behaviors and how these alterations associate with CVD markers. Fully understanding how energy balance is altered and the effects on body composition in pediatric CKD is critical to providing guidance to prevent the development of obesity in pediatric CKD, thus reducing risk factors for CVD.

Kogon’s major focus of research to date relates to the complications of pediatric CKD. She has authored studies of the longitudinal changes of blood pressure and the risk for uncontrolled hypertension, as well as issues related to psychosocial and neurocognitive complications in pediatric CKD. These studies have provided her with preliminary data regarding the importance of obesity within both the medical and psychosocial realms. Her preliminary data shows that obesity is significantly associated with depression and poor quality of life in children with CKD. As a result, this study will also look at behavioral aspects of children with chronic kidney disease compared to healthy children.

This study is innovative by including body composition as measured by dual-energy X-ray absorptiometry (DXA) to the evaluation of CVD risk factors in pediatric CKD. In addition, this is the first study to measure key components of energy balance simultaneously with direct comparison to controls and is unique in that it will directly measure body composition in relation to CVD markers. This study will also improve upon previously collected data regarding nutritional intake and physical activity by using gold standard measures of physical activity and dietary intake.

This study is distinctive in that it will combine precise physiology measures with behavioral measures (physical activity, dietary intake, eating behavior) in a population of children with CKD. Simultaneous consideration of both physiology and behavior is important when studying the complex trait of obesity, particularly when both are likely to be altered by the condition of living with CKD. This study will provide new data to identify the most important risk factors for the development of obesity and CVD risk, which ultimately will be used to improve the duration and quality of life of children with CKD.