Kidney Week

Abstract: TH-PO959

Association of Phase Angle with Cardiorespiratory Fitness and Physical Function in Patients on Maintenance Hemodialysis

Session Information

• Physical Activity and Lifestyle in Kidney Diseases
  October 24, 2024 | Location: Exhibit Hall, Convention Center
  Abstract Time: 10:00 AM - 12:00 PM

Category: Health Maintenance, Nutrition, and Metabolism

• 1500 Health Maintenance, Nutrition, and Metabolism

Authors

• Grace, Robbie Louise, Wake Forest University, Winston-Salem, North Carolina, United States

Robbie Louise Grace

• Dillman, Drake, Indiana University School of Medicine, Indianapolis, Indiana, United States

Drake Dillman, MS

• Groninger, Nolan, Indiana University School of Medicine, Indianapolis, Indiana, United States

Nolan Groninger

• Moe, Sharon M., Indiana University School of Medicine, Indianapolis, Indiana, United States

Sharon M. Moe, MD, FASN

• Karp, Sharon L., Indiana University School of Medicine, Indianapolis, Indiana, United States

Sharon L. Karp, MD, MPH

• Lim, Kenneth, Indiana University School of Medicine, Indianapolis, Indiana, United States

Kenneth Lim, MD, PhD, FASN

• Arroyo, Eliott, Wake Forest University, Winston-Salem, North Carolina, United States

Eliott Arroyo, PhD

Background

Phase angle (PhA) is a surrogate measure of cellular health and integrity of the cell membrane derived via bioelectrical impedance analysis. PhA has been shown to be predictive of muscle strength and physical function in healthy older adults. Herein, we sought to examine the relationship of PhA with cardiorespiratory fitness and physical function in patients on maintenance hemodialysis (HD).

Methods

This exploratory cross-sectional study used pooled data taken from previous trials conducted in the Division of Nephrology & Hypertension at the Indiana University School of Medicine. Participants completed a comprehensive battery of physical function assessments and a cardiopulmonary exercise test. Body composition and PhA were measured using bioelectrical impendence spectroscopy at a current frequency of 50 kHz. Multiple linear regression analyses were used to assess the association of PhA with peak oxygen uptake (VO₂Peak) and physical function outcomes.

Results

Group comparisons between patients on HD (n=27, 59% men, age=52 [12] y) and healthy controls (n=13, 38.5% men, age=53 [9] y) showed differences in race (p<0.001), however no differences in age, sex, or BMI. Patients on HD had a lower PhA (5.0 [1.4]°) compared with the controls (5.9 [0.6]°, p=0.005), even after adjusting for age, sex, and race (p=0.002). The HD group also had a lower short physical performance battery (SPPB) score (11 [8.3-12] versus 12 [12-12], p=0.002) and lower VO₂Peak (13.4 [3.7] mL*kg^–1*min^–1 versus 30.7 [0.6] mL*kg^–1*min^–1; p<0.001) compared with the controls. PhA in patients on HD was significantly associated with VO₂Peak (β=1.18, p=0.022) and SPPB score (β=0.92, p=0.006) on univariate regression. After adjusting for age, PhA remained significantly associated with SPPB score (β=0.71, p=0.032); however, it was no longer associated with VO₂Peak (β=1.01, p=0.055).

Conclusion

Patients on HD exhibit significant declines in PhA that are comparable with those observed in older (65+ years) adults and are associated with impaired physical function. Further prospective studies are needed to determine whether changes in PhA as kidney function declines are predictive of physical function decline in this vulnerable population.

Funding

• Private Foundation Support