Improving precision of bioimpedance spectroscopic analysis for lymphedema and lipedema assessment

Background: Bioimpedance spectroscopy (BIS) is commonly used for the detection and monitoring of lymphedema and potentially lipedema. BIS measures limb electrical resistance, which decreases with fluid accumulation in these conditions. R0, the index of extracellular fluid and lymph accumulation, is typically estimated using Cole modeling, but technical and biological factors can affect accuracy. Methods: Participants with clinically affirmed bilateral leg lymphedema, lipedema, self-ascribed swelling, and healthy controls were included in this study. Impedance measurements were taken using a stand-on BIS device, and R0 was estimated using both the Cole modeling method and a regression approach. Quality of data fitting was assessed visually and statistically. Results: Control participants were younger and lighter compared with the clinical groups. The regression method was able to analyze 100% of participant data, whereas the Cole method was successful in only 80%-88% of cases in the lymphedema and lipedema groups. Additionally, the regression approach provided better curve fitting accuracy for all participants. Conclusion: The regression method offers a robust alternative for estimating R0 values in BIS data, especially in lower limb assessments where data analysis is challenging. The small difference between methods in absolute R0 values (2.5%) has minimal practical implications, suggesting interchangeability in data analysis. The Cole method showed poorer performance, particularly in participants with lymphedema, possibly due to differences in water proportions and limb size. Overall, the regression method can be effectively used in clinical practice for estimating R0 values in BIS data, offering a more accurate and reliable approach than traditional Cole plotting methods.