Journal of Applied Physiology

Identification of fluid overload in elderly patients with chronic kidney disease using bioimpedance techniques

Usama Hussein, Monica Cimini, Garry J Handelman, Jochen G Raimann, Li Liu, Samer R Abbas, Peter Kotanko, null, Fredric O Finkelstein, Fansan Zhu


Diagnosis of fluid overload (FO) in early stage is essential to manage fluid balance of patients with chronic kidney disease (CKD) and to prevent cardiovascular disease (CVD). However, the identification of fluid status in patients with CKD is largely dependent on the physician's clinical acumen. The ratio of fluid overload to extracellular volume (FO/ECV) has been used as a reference to assess fluid status. The primary aim of this study was to compare FO/ECV with other bioimpedance methods and clinical assessments in patients with CKD. Whole body ECV, intracellular volume (ICV), total body water (TBW), and calf normalized resistivity (CNR) were measured (Hydra 4200). Thresholds of FO utilizing CNR and ECV/TBW were derived by receiver operator characteristic (ROC) analysis based on data from pooled patients with CKD and healthy subjects (HSs). Clinical assessments of FO in patients with CKD were performed by nephrologists. Patients with CKD (stage 3 and stage 4) (n = 50) and HSs (n = 189) were studied. The thresholds of FO were ≤14.3 (10-2 Ωm3/kg) for females and ≤13.1 (10-2 Ωm3/kg) for males using CNR and ≥0.445 in females and ≥0.434 in males using ECV/TBW. FO was diagnosed in 78%, 62%, and 52% of patients with CKD by CNR, FO/ECV, and ECV/TBW, respectively, whereas only 24% of patients with CKD were diagnosed to be FO by clinical assessment. The proportion of FO in patients with nondialysis CKD was largely underestimated by clinical assessment compared with FO/ECV, CNR, and ECV/TBW. CNR and FO/ECV methods were more sensitive than ECV/TBW in identifying fluid overload in these patients with CKD.NEW & NOTEWORTHY We found that fluid overload (FO) in patients with nondialysis CKD was largely underestimated by clinical assessment compared with bioimpedance methods, which was majorly due to lack of appropriate techniques to assess FO. In addition, although degree of FO by bioimpedance markers positively correlated with the age in healthy subjects (HSs), no difference was observed in the three hydration markers between groups of 50 ≤ age <70 yr and age ≥70 yr in the patients with CKD.

About the Contributors

Jochen G. Raimann, MD, PhD, MPH

Director, Data Analytics

Jochen has worked as a full-time scientist at RRI since his start as a postdoctoral research fellow in 2007. As Senior Manager of Clinical Data Analytics, Jochen conducts epidemiological research in dialysis and oversees many analytical projects. He has first- and co-authored numerous papers and also serves as Associate Editor of the journals Trials and Scientific Reports. ochen earned his MD from the Medical University Graz, his PhD from Maastricht University, and his MPH with a focus on epidemiology and biostatistics from the City University of New York School of Public Health.

Dr. Peter Kotanko, MD

RRI Research Director

SVP, Corporate Research & Development

Peter Kotanko, MD, is Research Director at the Renal Research Institute (RRI), New York. Prior to joining RRI, from 1997 to 2007 he served as vice chair of a department of internal medicine at an academic teaching hospital in Graz, Austria. Prior to moving to Graz in 1989, he worked from 1982 to 1989 in the Department of Physiology and the University Clinic of Internal Medicine in Innsbruck, Austria. From 1995 to 1996 he trained in nephrology at the Hammersmith Hospital, London, United Kingdom.

Fansan Zhu, PhD

Senior Research Scientist

Fansan was a lecturer in Dept of Bioengineering, Huazhong University of Science & Technology (HUST), Wuhan, China from 1992-1996. He holds master’s degrees in biomedical engineering from HUST and in Chemical engineering from Columbia University, New York. He received the PhD degree from University of Maastricht, Netherlands. His current research interests are application of bioimpedance, video image processing, body fluid dynamics and body composition and modeling of electrical properties in tissue. He is author of over 210 publications including peer-reviewed papers (67), chapter of books (5) and international conference proceedings (151). He is an inventor of 17 U.S. patents.