title: Serum Urate Levels Predict Joint Space Narrowing in Non-Gout Patients With Medial Knee Osteoarthritis.
abstract: The pathogenesis of osteoarthritis (OA) includes both mechanical and inflammatory features. Studies have implicated synovial fluid uric acid (UA) as a potential OA biomarker, possibly reflecting chondrocyte damage. Whether serum UA levels reflect/contribute to OA is unknown. We investigated whether serum UA levels predict OA progression in a non-gout knee OA population.
  
  
  
  Eighty-eight patients with medial knee OA (body mass index [BMI] <33 kg/m2) but without gout were studied. Baseline serum UA levels were measured in previously banked serum samples. At 0 and 24 months, patients underwent standardized weight-bearing fixed-flexion posteroanterior knee radiography to determine joint space width (JSW) and Kellgren/Lawrence grades. Joint space narrowing (JSN) was calculated as the change in JSW from 0 to 24 months. Twenty-seven patients underwent baseline contrast-enhanced 3T knee magnetic resonance imaging for assessment of synovial volume.
  
  
  
  Serum UA levels correlated with JSN values in both univariate (r = 0.40, P < 0.01) and multivariate (r = 0.28, P = 0.01) analyses. There was a significant difference in mean JSN after dichotomization at a serum UA cut point of 6.8 mg/dl, the solubility point for serum urate, even after adjustment (JSN of 0.90 mm for a serum UA ≥6.8 mg/dl and 0.31 mm for a serum UA <6.8 mg/dl; P < 0.01). Baseline serum UA levels distinguished progressors (JSN >0.2 mm) and fast progressors (JSN >0.5 mm) from nonprogressors (JSN ≤0.0 mm) in multivariate analyses (area under the receiver operating characteristic curve 0.63 [P = 0.03] and 0.62 [P = 0.05], respectively). Serum UA levels correlated with the synovial volume (r = 0.44, P < 0.01), a possible marker of JSN, although this correlation did not persist after controlling for age, sex, and BMI (r = 0.13, P = 0.56).
  
  
  
  In non-gout patients with knee OA, the serum UA level predicted future JSN and may serve as a biomarker for OA progression.
authors.affiliation: New York University School of Medicine, New York, New York.
authors.forename: Svetlana
authors.initials: S
authors.lastname: Krasnokutsky
authors.affiliation: New York University School of Medicine, New York, New York.
authors.forename: Charles
authors.initials: C
authors.lastname: Oshinsky
authors.affiliation: New York University School of Medicine, New York, New York.
authors.forename: Mukundan
authors.initials: M
authors.lastname: Attur
authors.affiliation: New York University School of Medicine, New York, New York.
authors.forename: Sisi
authors.initials: S
authors.lastname: Ma
authors.affiliation: New York University School of Medicine, New York, New York.
authors.forename: Hua
authors.initials: H
authors.lastname: Zhou
authors.affiliation: New York University School of Medicine, New York, New York.
authors.forename: Fangfei
authors.initials: F
authors.lastname: Zheng
authors.affiliation: New York University School of Medicine, New York, New York.
authors.forename: Meng
authors.initials: M
authors.lastname: Chen
authors.affiliation: New York University School of Medicine, New York, New York.
authors.forename: Jyoti
authors.initials: J
authors.lastname: Patel
authors.affiliation: New York University School of Medicine, New York, New York.
authors.forename: Jonathan
authors.initials: J
authors.lastname: Samuels
authors.affiliation: New York University School of Medicine, New York, New York.
authors.forename: Virginia C
authors.initials: VC
authors.lastname: Pike
authors.affiliation: New York University School of Medicine, New York, New York.
authors.forename: Ravinder
authors.initials: R
authors.lastname: Regatte
authors.affiliation: New York University School of Medicine, New York, New York.
authors.forename: Jenny
authors.initials: J
authors.lastname: Bencardino
authors.affiliation: New York University School of Medicine, New York, New York.
authors.forename: Leon
authors.initials: L
authors.lastname: Rybak
authors.affiliation: New York University School of Medicine, New York, New York.
authors.forename: Steven
authors.initials: S
authors.lastname: Abramson
authors.affiliation: New York University School of Medicine, New York, New York.
authors.forename: Michael H
authors.initials: MH
authors.lastname: Pillinger
mesh_terms: D015415:Biomarkers / Q000097:blood; D018450:Disease Progression; D005260:Female; D006801:Humans; D017746:Joint Capsule / Q000000981:diagnostic imaging / Q000473:pathology*; D007719:Knee Joint / Q000000981:diagnostic imaging / Q000473:pathology*; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D020370:Osteoarthritis, Knee / Q000097:blood* / Q000473:pathology; D011237:Predictive Value of Tests; D012372:ROC Curve; D011859:Radiography / Q000379:methods; D014527:Uric Acid / Q000097:blood*; D016474:Weight-Bearing
chemical_list: D015415:Biomarkers; D014527:Uric Acid