Hemodialysis International

Estimation of fluid status using three multifrequency bioimpedance methods in hemodialysis patients

Lin-Chun Wang, Jochen G Raimann, Xia Tao, Priscila Preciado, Ohnmar Thwin, Laura Rosales, Stephan Thijssen, Peter Kotanko, Fansan Zhu

Abstract

Introduction: Segmental eight-point bioimpedance has been increasingly used in practice. However, whether changes in bioimpedance analysis components before and after hemodialysis (HD) using this technique in a standing position is comparable to traditional whole-body wrist-to-ankle method is still unclear. We aimed to investigate the differences between two eight-point devices (InBody 770 and Seca mBCA 514) and one wrist-to-ankle (Hydra 4200) in HD patients and healthy subjects in a standing position.

Methods: Thirteen HD patients were studied pre- and post-HD, and 12 healthy subjects once. Four measurements were performed in the following order: InBody; Seca; Hydra; and InBody again. Electrical equivalent models by each bioimpedance method and the fluid volume estimates by each device were also compared.

Findings: Overall, total body water (TBW) was not different between the three devices, but InBody showed lower extracellular water (ECW) and higher intracellular water (ICW) compared to the other two devices. When intradialytic weight loss was used as a surrogate for changes in ECW (∆ECW) and changes in TBW (∆TBW), ∆ECW was underestimated by Hydra (-0.79 ± 0.89 L, p < 0.01), InBody (-1.44 ± 0.65 L, p < 0.0001), and Seca (-0.32 ± 1.34, n.s.). ∆TBW was underestimated by Hydra (-1.14 ± 2.81 L, n.s.) and InBody (-0.52 ± 0.85 L, p < 0.05) but overestimated by Seca (+0.93 ± 3.55 L, n.s.).

Discussion: Although segmental eight-point bioimpedance techniques provided comparable TBW measurements not affected by standing over a period of 10-15 min, the ECW/TBW ratio appeared to be significantly lower in InBody compared with Seca and Hydra. Results from our study showed lack of agreement between different bioimpedance devices; direct comparison of ECW, ICW, and ECW/TBW between different devices should be avoided and clinicians should use the same device to track the fluid status in their HD population in a longitudinal direction.

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.

Laura Rosales, MD, MPH

Director, Research Medical Education & Information

Laura obtained her MD degree from the Central University in Quito, Ecuador, and a master’s degree in public health from Columbia University, New York. She was a research fellow for Beth Israel Medical Center in partnership with RRI and was the Research Associate Lab Director at RRI for several years. Laura is an accomplished scientist with ample experience in clinical research for more than 16 years and has authored and co-authored numerous publications in peer-reviewed journals.

Stephan Thijssen, MD

Vice President, Applied and Basic Research

Prior to coming to New York, Stephan worked in the Nephrology Department at the University Hospital Homburg, Germany. He joined RRI in 2005. Stephan brings more than one and a half decades of research experience to the RRI team, covering laboratory research, clinical research, epidemiology research, and mathematical modeling. He has written and published an extensive number of scholarly articles in leading national and international peer-reviewed scientific journals and published several book chapters.

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.