title: TSG-6 activity as a novel biomarker of progression in knee osteoarthritis.
abstract: OBJECTIVE
  To establish whether there is an association between TSG-6 activity and osteoarthritis progression.
  
  
  METHODS
  TSG-6 activity was determined in 132 synovial fluids from patients with OA of the knee, using a novel quantitative TSG-6 activity assay. The association between TSG-6 activities at baseline and four distinct disease progression states, determined at 3-year follow-up, was analyzed using logistic regression.
  
  
  RESULTS
  There was a statistically significant relationship between TSG-6 activity at baseline and all OA progression states over a 3-year period. Patient knees with TSG-6 activities in the top tenth percentile, compared to the median activity, had an odds ratio (OR) of at least 7.86 (confidence interval (CI) [3.2, 20.5]) for total knee arthroplasty (TKA) within 3 years, and of at least 5.20 (CI [1.8, 13.9]) after adjustment for confounding factors. Receiver operating characteristic (ROC) analysis for knee arthroplasty yielded a cut-off point of 13.3 TSG-6 activity units/ml with the following parameters: area under the curve 0.90 (CI [0.804, 0.996]), sensitivity 0.91 (CI [0.59, 0.99]), specificity 0.82 (CI [0.74, 0.88]) and a negative predictive value (NPV) of 0.99 (CI [0.934, 0.994]).
  
  
  CONCLUSIONS
  The TSG-6 activity is a promising independent biomarker for OA progression. Given the high NPV, this assay may be particularly suitable for identifying patients at low risk of rapid disease progression and to assist in the timing of arthroplasty.
authors: Department of Microbiology, New York University, School of Medicine, New York, NY 10016, USA. Electronic address: hans-georg.wisniewski@med.nyu.edu.
authors: H-G
authors: HG
authors: Wisniewski
authors: Department of Microbiology, New York University, School of Medicine, New York, NY 10016, USA.
authors: E
authors: E
authors: Colón
authors: Department of Statistics, Harvard University, Cambridge, MA 02138, USA.
authors: V
authors: V
authors: Liublinska
authors: Department of Orthopedic Surgery, New York University, School of Medicine, and NYU Hospital for Joint Diseases, New York, NY 10003, USA.
authors: R J
authors: RJ
authors: Karia
authors: Department of Medicine, Duke University, School of Medicine, Durham, NC 27710, USA.
authors: T V
authors: TV
authors: Stabler
authors: Department of Medicine, New York University, School of Medicine, and NYU Hospital for Joint Diseases, New York, NY 10003, USA.
authors: M
authors: M
authors: Attur
authors: Department of Medicine, New York University, School of Medicine, and NYU Hospital for Joint Diseases, New York, NY 10003, USA.
authors: S B
authors: SB
authors: Abramson
authors: Department of Orthopedic Surgery, New York University, School of Medicine, and NYU Hospital for Joint Diseases, New York, NY 10003, USA; Department of Biochemistry and Molecular Pharmacology, NYU School of Medicine, New York, NY 10016, USA.
authors: P A
authors: PA
authors: Band
authors: Department of Medicine, Duke University, School of Medicine, Durham, NC 27710, USA.
authors: V B
authors: VB
authors: Kraus
mesh_terms: D000368:Aged; D019645:Arthroplasty, Replacement, Knee; D015415:Biomarkers / Q000378:metabolism; D015815:Cell Adhesion Molecules / Q000378:metabolism*; D018450:Disease Progression; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000175:diagnosis / Q000378:metabolism* / Q000601:surgery; D011379:Prognosis; D012720:Severity of Illness Index; D013582:Synovial Fluid / Q000378:metabolism
chemical_list: D015415:Biomarkers; D015815:Cell Adhesion Molecules; C072273:TNFAIP6 protein, human
keywords: Biomarker; Logistic regression; Osteoarthritis progression; ROC curve; TSG-6 activity