Kidney Week

Abstract: TH-PO1215

Air Displacement Plethysmography Unmasks Body Composition Derangement in an Infant with ESRD

Session Information

• Pediatric Nephrology: CV Health, CKD, AKI, Dialysis, Transplantation, and Health Services Research
  October 22, 2026 | Location: Exhibit Hall A, Convention Center
  Abstract Time: 10:00 AM - 12:00 PM

Category: Pediatric Nephrology

• 1800 Pediatric Nephrology

Authors

• Pierce, Keith, Indiana University School of Medicine, Indianapolis, Indiana, United States

Keith Pierce, MD, MS

• Wilson, Amy C., Indiana University School of Medicine, Indianapolis, Indiana, United States

Amy C. Wilson, MD

• Liberio, Brianna M., Indiana University School of Medicine, Indianapolis, Indiana, United States

Brianna M. Liberio, MD

• Slagle, Cara L., Indiana University School of Medicine, Indianapolis, Indiana, United States

Cara L. Slagle, MD

• Starr, Michelle C., Indiana University School of Medicine, Indianapolis, Indiana, United States

Michelle C. Starr, MD, MPH, FASN

Introduction

Growth failure and malnutrition are common in infants with chronic kidney disease (CKD) and end stage renal disease (ESRD). Weight and length, which are the standard measurements, are confounded by fluid retention, altered bone-mineral metabolism, and atypical growth trajectories. Air displacement plethysmography (ADP) by PEA POD (COSMED) is an FDA-approved method of measuring body composition. It is clinically established in neonatal care, but, to our knowledge, has not previously been described in infants with CKD. We report what we believe to be the first such application.

Case Description

A male infant born at 36 weeks’ gestation with congenital kidney failure underwent serial ADP measurements. Measurements were obtained at chronologic ages of 9, 11, 12, and 19 weeks with no adverse events. All measurements were after starting dialysis. At the first measurement, body mass was 4.33 kg (33rd %). ADP revealed %Fat z-score +5.07 (>99th %) with fat free mass (FFM) z-score −2.17 (1st %). Over 11 weeks of serial monitoring, FFM rose from 2.89 kg to 4.24 kg while fat mass rose from 1.44 kg to 1.82 kg. The %Fat z recovered to +0.88, and FFM z partially recovered to −1.14. However, a clinically meaningful FFM deficit persisted, despite weight gain that conventional metrics would have judged appropriate.

Discussion

This case illustrates the challenges in assessing growth in infants with CKD and demonstrates the utility of a novel method for evaluating this population. This infant tracked near the 50th weight percentile while ADP demonstrated a profound lean-mass deficit with concurrent adiposity excess. ADP is feasible, safe, and reproducible in this population, with serial measurements achievable during routine care. In this case, serial ADP revealed a persistent FFM deficit that would have escaped detection by anthropometrics alone. Systematic body composition assessment may refine nutritional and dialysis decision-making in infants with CKD and ESRD. Larger prospective evaluation is ongoing.