title: Association of serum C-reactive protein and erythrocyte sedimentation rate with muscle strength in patients with knee osteoarthritis.
abstract: OBJECTIVE
  To examine the association of serum CRP and ESR with muscle strength in patients with knee OA.
  
  
  METHODS
  Cross-sectional data from 285 patients with knee OA from the Amsterdam Osteoarthritis (AMS-OA) cohort were analysed. CRP (mg/l) and ESR (mm/l) were measured in serum from patients' blood samples and the values were dichotomized for the analyses. Strength of quadriceps and hamstring muscles was assessed using an isokinetic dynamometer. Univariable and multivariable linear regression analyses were used to assess the association of CRP and ESR with muscle strength, adjusting for relevant confounders.
  
  
  RESULTS
  Elevated levels of serum CRP (β = -0.10; P = 0.04) and ESR (β = -0.12; P = 0.02) were associated with lower muscle strength after adjustment for age, sex, comorbidities and NSAID use. The associations were no longer significant when BMI was incorporated in the adjusted model.
  
  
  CONCLUSIONS
  Inflammation might influence muscle strength in patients with knee OA. Moreover, the link between inflammation and obesity might explain the effect that BMI has in the associations between inflammatory markers (i.e. CRP and ESR) and muscle strength.
authors.affiliation: Amsterdam Rehabilitation Research Center | Reade, Amsterdam, The Netherlands. d.c.sanchezramirez@vu.nl
authors.forename: Diana C
authors.initials: DC
authors.lastname: Sanchez-Ramirez
authors.forename: Marike
authors.initials: M
authors.lastname: van der Leeden
authors.forename: Martin
authors.initials: M
authors.lastname: van der Esch
authors.forename: Martijn
authors.initials: M
authors.lastname: Gerritsen
authors.forename: Leo D
authors.initials: LD
authors.lastname: Roorda
authors.forename: Sabine
authors.initials: S
authors.lastname: Verschueren
authors.forename: Jaap
authors.initials: J
authors.lastname: van Dieën
authors.forename: Joost
authors.initials: J
authors.lastname: Dekker
authors.forename: Willem F
authors.initials: WF
authors.lastname: Lems
mesh_terms: D000368:Aged; D015415:Biomarkers / Q000097:blood; D001799:Blood Sedimentation; D015992:Body Mass Index; D002097:C-Reactive Protein / Q000378:metabolism*; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007249:Inflammation / Q000097:blood; D008297:Male; D008875:Middle Aged; D053580:Muscle Strength / Q000502:physiology*; D020370:Osteoarthritis, Knee / Q000503:physiopathology*; D052097:Quadriceps Muscle; D012044:Regression Analysis
chemical_list: D015415:Biomarkers; D002097:C-Reactive Protein