title: Dialysis modality and nutritional status are associated with variability of inflammatory markers.
abstract: Inflammation is a common feature in dialysis patients and is associated with cardiovascular complications and poor outcome. Measuring the variability of inflammatory markers may help in understanding underlying factors triggering inflammation. Whether the inflammatory pattern in hemodialysis (HD) and peritoneal dialysis (PD) patients differs has scarcely been studied. Here we explored factors associated with the magnitude and variability of inflammation markers in HD and PD patients.
  
  
  
  In two 3-month, prospective cohort studies comprising 228 prevalent HD and 80 prevalent PD patients, interleukin-6 (IL-6) and high-sensitivity C-reactive protein (CRP) were measured in blood samples drawn each month and every week, respectively. Information on comorbidity, protein-energy wasting (PEW) and medications was gathered at baseline, and information on symptoms potentially related to inflammation was gathered weekly. A mixed-effect model was used for multivariate analysis of factors linked to CRP and IL-6 variation.
  
  
  
  IL-6 and CRP levels were higher and showed higher variability in HD versus PD patients [median IL-6 8.3 (interquartile range, IQR, 5.3-14.5) versus 6.7 (IQR 4.2-10.0) pg/mL, P < 0.001 and median CRP 6.1 (IQR 2.5-14.0) versus 5.4 (IQR 1.6-9.0) mg/L, P < 0.001). PEW predicted increased inflammation variability after correcting for age, sex, dialysis vintage, modality and comorbidity. Increased comorbidity predicted IL-6, but not CRP, variability.
  
  
  
  Circulating concentrations as well as variability of IL-6 and CRP levels were higher in HD as compared with PD patients. In HD and PD patients, short-term variability of IL-6 and CRP levels associated strongly with PEW, while comorbidity was related to IL-6 but not to CRP variability.
authors.affiliation: Division of Renal Medicine, Department of Clinical Science, Intervention and Technology, Karolinska Institutet, Karolinska University Hospital, Stockholm, Sweden Landspitali University Hospital, Reykjavik, Iceland.
authors.forename: Sunna
authors.initials: S
authors.lastname: Snaedal
authors.affiliation: Division of Baxter Novum, Department of Clinical Science, Intervention and Technology, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Abdul R
authors.initials: AR
authors.lastname: Qureshi
authors.affiliation: Faculty of Medicine, University of Iceland, Reykjavik, Iceland.
authors.forename: Sigrún H
authors.initials: SH
authors.lastname: Lund
authors.affiliation: Clinical Sciences, Danderyd Hospital, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Guna
authors.initials: G
authors.lastname: Germanis
authors.affiliation: Division of Renal Medicine, Department of Clinical Science, Intervention and Technology, Karolinska Institutet, Karolinska University Hospital, Stockholm, Sweden.
authors.forename: Britta
authors.initials: B
authors.lastname: Hylander
authors.affiliation: Division of Renal Medicine, Department of Clinical Science, Intervention and Technology, Karolinska Institutet, Karolinska University Hospital, Stockholm, Sweden.
authors.forename: Olof
authors.initials: O
authors.lastname: Heimbürger
authors.affiliation: Division of Renal Medicine, Department of Clinical Science, Intervention and Technology, Karolinska Institutet, Karolinska University Hospital, Stockholm, Sweden.
authors.forename: Juan J
authors.initials: JJ
authors.lastname: Carrero
authors.affiliation: Division of Renal Medicine, Department of Clinical Science, Intervention and Technology, Karolinska Institutet, Karolinska University Hospital, Stockholm, Sweden.
authors.forename: Peter
authors.initials: P
authors.lastname: Stenvinkel
authors.affiliation: Division of Renal Medicine, Department of Clinical Science, Intervention and Technology, Karolinska Institutet, Karolinska University Hospital, Stockholm, Sweden.
authors.forename: Peter
authors.initials: P
authors.lastname: Bárány
mesh_terms: D000368:Aged; D015415:Biomarkers / Q000097:blood; D002097:C-Reactive Protein / Q000378:metabolism*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007249:Inflammation / Q000097:blood*; D015850:Interleukin-6 / Q000097:blood*; D007676:Kidney Failure, Chronic / Q000378:metabolism / Q000628:therapy*; D008297:Male; D008875:Middle Aged; D009752:Nutritional Status; D011446:Prospective Studies; D006435:Renal Dialysis / Q000379:methods*
chemical_list: D015415:Biomarkers; D015850:Interleukin-6; D002097:C-Reactive Protein
keywords: ESRD; comorbidity; inflammation; nutritional status; variability