title: Utility of a novel inflammatory marker, GlycA, for assessment of rheumatoid arthritis disease activity and coronary atherosclerosis.
abstract: BACKGROUND
  GlycA is a novel inflammatory biomarker measured using nuclear magnetic resonance (NMR). Its NMR signal primarily represents glycosylated acute phase proteins. GlycA was associated with inflammation and development of cardiovascular disease in initially healthy women. We hypothesized that GlycA is a biomarker of disease activity and is associated with coronary artery atherosclerosis in patients with rheumatoid arthritis (RA).
  
  
  METHODS
  We conducted a cross-sectional study of 166 patients with RA and 90 control subjects. GlycA was measured from an NMR signal originating from N-acetylglucosamine residues on circulating glycoproteins. The relationship between GlycA and RA disease activity (Disease Activity Score based on 28 joints (DAS28)) and coronary artery calcium score was determined.
  
  
  RESULTS
  GlycA concentrations were higher in patients with RA (median (interquartile range): 398 μmol/L (348 to 473 μmol/L)) than control subjects (344 μmol/L (314 to 403 μmol/L) (P < 0.001). In RA, GlycA was strongly correlated with DAS28 based on erythrocyte sedimentation rate (DAS28-ESR) and DAS28 based on C-reactive protein (DAS28-CRP) and their components, including tender and swollen joint counts, global health score, ESR and CRP (all P < 0.001). The area under the receiver operating characteristic curve for GlycA's ability to differentiate between patients with low versus moderate to high disease activity based on DAS28-CRP was 0.75 (95% confidence interval (CI): 0.68, 0.83). For each quartile increase in GlycA, the odds of having coronary artery calcium increased by 48% (95% CI: 4%, 111%), independent of age, race and sex (P = 0.03).
  
  
  CONCLUSIONS
  GlycA is a novel inflammatory marker that may be useful for assessment of disease activity and is associated with coronary artery atherosclerosis in patients with RA.
authors.affiliation: Department of Medicine, Vanderbilt University Medical Center, 1161 21st Avenue South, T-3113 MCN, Nashville, TN, 37212, USA. michelle.ormseth@vanderbilt.edu.
authors.forename: Michelle J
authors.initials: MJ
authors.lastname: Ormseth
authors.affiliation: Department of Medicine, Vanderbilt University Medical Center, 1161 21st Avenue South, T-3113 MCN, Nashville, TN, 37212, USA. c.chung@vanderbilt.edu.
authors.forename: Cecilia P
authors.initials: CP
authors.lastname: Chung
authors.affiliation: Department of Medicine, Vanderbilt University Medical Center, 1161 21st Avenue South, T-3113 MCN, Nashville, TN, 37212, USA. annette.oeser@vanderbilt.edu.
authors.forename: Annette M
authors.initials: AM
authors.lastname: Oeser
authors.affiliation: LabCorp, 2500 Sumner Blvd, Raleigh, NC, 27616, USA. margery.commelly@liposcience.com.
authors.forename: Margery A
authors.initials: MA
authors.lastname: Connelly
authors.affiliation: Department of Rheumatology, University of Eastern Finland, Jyvaskyla Central Hospital, 40620, Jyvaskyla, Finland. tuulikki.sokka-isler@ksshp.fi.
authors.forename: Tuulikki
authors.initials: T
authors.lastname: Sokka
authors.affiliation: Department of Medicine, University of Alberta, 4A7.050, 8440 - 112 Street, Edmonton, AB, T6G 2B7, Canada. raggip@gmail.com.
authors.forename: Paolo
authors.initials: P
authors.lastname: Raggi
authors.affiliation: Department of Medicine, Vanderbilt University Medical Center, 1161 21st Avenue South, T-3113 MCN, Nashville, TN, 37212, USA. joseph.f.solus@vanderbilt.edu.
authors.forename: Joseph F
authors.initials: JF
authors.lastname: Solus
authors.affiliation: LabCorp, 2500 Sumner Blvd, Raleigh, NC, 27616, USA. jotvos@liposcience.com.
authors.forename: James D
authors.initials: JD
authors.lastname: Otvos
authors.affiliation: Department of Medicine, Vanderbilt University Medical Center, 1161 21st Avenue South, T-3113 MCN, Nashville, TN, 37212, USA. mike.stein@vanderbilt.edu.
authors.forename: C Michael
authors.initials: CM
authors.lastname: Stein
mesh_terms: D019540:Area Under Curve; D001172:Arthritis, Rheumatoid / Q000150:complications / Q000473:pathology*; D015415:Biomarkers / Q000032:analysis*; D003324:Coronary Artery Disease / Q000209:etiology / Q000473:pathology*; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008297:Male; D008875:Middle Aged; D012372:ROC Curve
chemical_list: D015415:Biomarkers