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Abstract: PO1271

Phase Angle and Extracellular Mass to Body Cell Mass Ratio in Peritoneal Dialysis

Session Information

Category: Dialysis

  • 703 Dialysis: Peritoneal Dialysis

Authors

  • Domingos, Ana T., Centro Hospitalar do Algarve EPE, Faro, Faro, Portugal
  • Marques, Roberto Calças, Centro Hospitalar do Algarve EPE, Faro, Faro, Portugal
  • Guedes, Anabela M., Centro Hospitalar do Algarve EPE, Faro, Faro, Portugal
  • Laranjo, Céu, Centro Hospitalar do Algarve EPE, Faro, Faro, Portugal
  • Bernardo, Idalécio, Centro Hospitalar do Algarve EPE, Faro, Faro, Portugal
  • Neves, Pedro Leao, Centro Hospitalar do Algarve EPE, Faro, Faro, Portugal
Background

Extracellular mass to body cell mass ratio (ECM/BCMr) is an important marker of malnutrition and a described independent predictor of long-term survival in Peritoneal Dialysis (PD). Its potential as dual index of wasting-fluid overload has been explored in Hemodialysis (HD). Phase angle (PA) – a predictor of long-term survival in dialysis – also appears as a potential nutritional-evaluation tool, with some authors defining protein-energy wasting as PA <4.5°. Higher ECM/BCMr would indicate either lower muscle mass and/or fluid overload. Its adequate cut-off point in PD remains unclear. Reports in CKD/HD-patients suggest a cut-off point ≥1.20, which added to a PA value <6, would work as markers of poor cardiovascular prognosis. But, how could these markers work in our population?

Methods

A prospective study included patients’ first simultaneous acquisition of bioelectrical impedance analysis (BIA) and peritoneal equilibration test (PET). Phase angle at 50 kHz was recorded. Spearman correlation and T-student analysis were used.

Results

Were included 67 patients, with a mean age of 54.1±17.3 years, 59.7% men, 95.5% Caucasian, 84.4% hypertensive and 31.3% diabetic. Mean ECM/BCMr was 0.57±0.03 and mean PA was 5.12±0.3°. ECM/BCMr is positively correlated with age (r=0.293, p=0.017), pulse pressure (r=0.334, p=0.006=), ECW/TBW (r=0.948, p<0.01) and TBW/FFM (r=0.678, p<0.01), and inversely with albumin (r=-0.477, p=<0.01), uric acid (r=-0.287, p=0.027) and GFR (r=-0.308, p=0.012). A higher ECM/BCMr was observed among diabetics (0.59 vs. 0.56, p=0.011). PA is directly correlated with albumin (r=0.364, p=0.013) and GFR (r=0.291, p=0.049). Inverse correlations are described with ECW/TBW (r=-0.888, p<0.01), TBW/FFM (r=-0.674, p<0.01), ECM/BCMr (r=-0.909, p<0.01), age (r=-0.323, p=0.029) and diabetes (r=-0.312, p=0.035).

Conclusion

ECM/BCM and PA correlate with several volume and nutrition markers and work “contrariwise”. Our population is prone to a poorer cardiovascular prognosis and eventually malnutrition, considering these cut-offs. Since BIA is a non-invasive, easily and periodically applied method, we believe that approval of these markers as dual index could be applied to PD, although admitting that this population would probably require new cut-offs.