Kidney Week

Abstract: FR-PO0402

Optimal Methodology for Peak Oxygen Uptake (VO2 Peak) Sampling Interval in Patients on Hemodialysis

Session Information

• Dialysis: Measuring and Managing Symptoms and Syndromes
  November 07, 2025 | Location: Exhibit Hall, Convention Center
  Abstract Time: 10:00 AM - 12:00 PM

Category: Dialysis

• 801 Dialysis: Hemodialysis and Frequent Dialysis

Authors

• Stafford, Lauren H., Indiana University School of Medicine, Indianapolis, Indiana, United States

Lauren H. Stafford, MS

• Campos, Monique Opuszcka, Indiana University School of Medicine, Indianapolis, Indiana, United States

Monique Opuszcka Campos, PhD

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

Nolan Groninger, MPH

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

Drake Dillman, MS

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

Kenneth Lim, MD, PhD, FASN

Group or Team Name

• Lim Lab.

Background

Cardiopulmonary exercise testing (CPET) is the gold-standard diagnostic tool for determining oxygen uptake at peak exercise (VO₂Peak). VO₂Peak is an index of cardiovascular functional capacity and is significantly impaired in patients on hemodialysis (HD). VO₂Peak is typically averaged using intervals between 10s-60s. However, there are no universally accepted methods for averaging VO₂Peak in patients on dialysis. Herein, we sought to determine the optimal VO₂Peak sampling interval in patients on HD compared to controls.

Methods

We conducted a cross-sectional, secondary analysis using the Comparison of the Self-Paced versus Ramp Incremental Exercise Protocols on Patients with Kidney Failure (SPARK) cohort. Patients on HD (n=12) and healthy controls (CON) (n=24) completed two CPET visits. VO₂Peak sampling intervals were averaged during the last 10, 20, 30, and 60 seconds of exercise. Kruskal-Wallis test comparisons were performed for continuous data. Reliability of each sampling interval was assessed by coefficient of variation (CV) between the two CPET visits.

Results

Groups were matched in age and gender (P>0.05). BMI was higher in HD group (28.6±4.9 kg/m²) compared to the CON group (25.4±2.7 kg/m²; P=0.04). The median VO₂Peak for the 60s sampling interval (11.2 [10.2, 13.9] mL/kg/min) was significantly lower (P=0.007) than the 10s (11.6 [10.0, 14.6] mL/kg/min), 20s (11.8 [10.0, 14.4] mL/kg/min), and 30s (11.5 [10.8, 14.7] mL/kg/min). The same trend was observed in the CON group with significantly lower VO₂Peak values at the 60s interval (28.3 [24.4, 34.7] mL/kg/min) compared to shorter intervals (P<0.001). VO₂Peak measurements exhibited low variability between CPET visits in both HD and CON groups. The median CV in the HD group ranged from 4.2% to 5.8% across the different intervals, with no significant differences observed (P=0.59). Similarly, the median CV for the control group showed no differences between the intervals, ranging from 1.9% to 2.9% (P=0.52).

Conclusion

Longer sampling intervals (60s) significantly reduce VO₂Peak in both HD and CON participants, while 10s, 20s, and 30s intervals showed no significant difference. The consistently low CV across all intervals in both groups supports the standardization of shorter VO₂Peak sampling intervals.

Funding

• Other NIH Support

Digital Object Identifier (DOI)

• doi: 10.1681/ASN.20257810xczz