title: Phase Angle Predicts Arterial Stiffness and Vascular Calcification in Peritoneal Dialysis Patients.
abstract: OBJECTIVE
  Fluid overload (FO) is frequently present in peritoneal dialysis (PD) patients and is associated with markers of malnutrition, inflammation, and atherosclerosis/calcification (MIAC) syndrome. We examined the relationships in stable PD patients between phase angle (PhA) and the spectrum of uremic vasculopathy including vascular calcification and arterial stiffness and between PhA and changes in serum fetuin-A levels.
  
  
  METHODS
  Sixty-one stable adult PD patients were evaluated in a cross-sectional study (ST1). Phase angle was measured by multifrequency bioimpedance analysis (InbodyS10, Biospace, Korea) at 50 kHz. Augmentation index (AI), a surrogate marker of arterial stiffness, was assessed by digital pulse amplitude tonometry (Endo PAT, Itamar Medical, Caesarea, Israel). Vascular calcification was assessed by simplified calcification score (SCS). Serum fetuin-A levels were measured by ELISA (Thermo scientific; Waltham, MA, USA). Serum albumin was used as a nutritional marker, and serum C-reactive protein (CRP) was used as an inflammatory marker. The same assessments were carried out longitudinally (ST2) in the first 33 patients who completed 1 year of evaluation in ST1.
  
  
  RESULTS
  In ST1, patients with PhA < 6° had higher CRP levels, AI, and SCS and lower serum albumin and fetuin-A levels, in comparison with patients with PhA ≥ 6°. In addition, PhA was a predictor of both AI (β = -0.351,p= 0.023) and SCS ≥ 3 (EXP (B) = 0.243,p= 0.005). In ST2, the increase of PhA over time was associated with decreases in both AI (r= -0.378,p= 0.042) and CRP levels (r= -0.426,p= 0.021), as well as with the increase in serum fetuin-A levels (r= 0.411,p= 0.030).
  
  
  CONCLUSIONS
  Phase angle predicts both arterial stiffness and vascular calcification in stable PD patients.
authors.affiliation: i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Portugal margarida.sarmentodias@gmail.com.|INEB - Instituto de Engenharia Biomédica, Universidade do Porto, Porto, Portugal.|Faculdade de Ciências da Nutrição e Alimentação, Universidade do Porto, Portugal.
authors.forename: Margarida
authors.initials: M
authors.lastname: Sarmento-Dias
authors.affiliation: Serviço de Nefrologia, Centro Hospitalar de São João, EPE, Porto, Portugal.|Unidade de Investigação e Desenvolvimento Cardiovascular, Faculdade de Medicina, Universidade do Porto.
authors.forename: Carla
authors.initials: C
authors.lastname: Santos-Araújo
authors.affiliation: Faculdade de Ciências da Nutrição e Alimentação, Universidade do Porto, Portugal.
authors.forename: Rui
authors.initials: R
authors.lastname: Poínhos
authors.affiliation: Faculdade de Ciências da Nutrição e Alimentação, Universidade do Porto, Portugal.
authors.forename: Bruno
authors.initials: B
authors.lastname: Oliveira
authors.affiliation: Serviço de Nefrologia, Centro Hospitalar de São João, EPE, Porto, Portugal.
authors.forename: Maria
authors.initials: M
authors.lastname: Sousa
authors.affiliation: i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Portugal.|INEB - Instituto de Engenharia Biomédica, Universidade do Porto, Porto, Portugal.|Departamento de Doenças Renais Urológicas e Infecciosas, Faculdade de Medicina, Universidade do Porto, Porto, Portugal.
authors.forename: Liliana
authors.initials: L
authors.lastname: Simões-Silva
authors.affiliation: i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Portugal.|INEB - Instituto de Engenharia Biomédica, Universidade do Porto, Porto, Portugal.
authors.forename: Isabel
authors.initials: I
authors.lastname: Soares-Silva
authors.affiliation: i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Portugal.|INEB - Instituto de Engenharia Biomédica, Universidade do Porto, Porto, Portugal.|Faculdade de Ciências da Nutrição e Alimentação, Universidade do Porto, Portugal.
authors.forename: Flora
authors.initials: F
authors.lastname: Correia
authors.affiliation: i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Portugal.|INEB - Instituto de Engenharia Biomédica, Universidade do Porto, Porto, Portugal.|Serviço de Nefrologia, Centro Hospitalar de São João, EPE, Porto, Portugal.|Departamento de Doenças Renais Urológicas e Infecciosas, Faculdade de Medicina, Universidade do Porto, Porto, Portugal.
authors.forename: Manuel
authors.initials: M
authors.lastname: Pestana
mesh_terms: D000328:Adult; D001823:Body Composition; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007676:Kidney Failure, Chronic / Q000150:complications / Q000378:metabolism / Q000628:therapy*; D008137:Longitudinal Studies; D008297:Male; D010530:Peritoneal Dialysis / Q000009:adverse effects*; D061205:Vascular Calcification / Q000209:etiology*; D059289:Vascular Stiffness / Q000502:physiology*; D014882:Water-Electrolyte Balance / Q000502:physiology*; D055815:Young Adult; D060749:alpha-2-HS-Glycoprotein / Q000378:metabolism
chemical_list: D060749:alpha-2-HS-Glycoprotein
keywords: Phase angle; arterial stiffness; fetuin-A; peritoneal dialysis; vascular calcification