title: What Is the Relationship Between Morning Symptoms and Measures of Disease Activity in Patients With Rheumatoid Arthritis?
abstract: OBJECTIVE
  Little is known about the relationship between morning symptoms of rheumatoid arthritis (RA) and measures of disease activity currently used to assess RA. Information available from the Circadian Administration of Prednisone in Rheumatoid Arthritis (CAPRA-2) study was used to investigate these relationships.
  
  
  METHODS
  CAPRA-2 included 350 patients with RA who were symptomatic despite treatment with disease-modifying antirheumatic drugs, randomized 2:1 to additional treatment with a 5-mg daily dose of delayed-release prednisone or placebo. Pearson's correlations were used to evaluate the relationships between change from baseline in symptoms (duration of morning stiffness, severity of morning stiffness, and intensity of pain on waking) and measures of disease activity (the American College of Rheumatology 20% improvement criteria [ACR20], the Disease Activity Score in 28 joints [DAS28], and the Health Assessment Questionnaire disability index). Correlations were defined as weak (<0.3), moderate (0.3-0.7), or strong (>0.7).
  
  
  RESULTS
  There was a strong correlation between the severity of morning stiffness and the intensity of morning pain (Pearson's correlation 0.91, P < 0.001). There was a weak correlation between the duration of morning stiffness and measures of disease activity (0.24-0.28), with moderate correlations between the severity of morning stiffness or intensity of pain on waking and DAS28 or ACR20 scores (0.44-0.48). Severity of morning stiffness showed less variability and a greater effect size than did duration of morning stiffness.
  
  
  CONCLUSIONS
  Morning symptoms and measures of disease activity show weak to moderate correlations. Severity of morning stiffness showed less variability and greater effect size than did duration of morning stiffness. These findings suggest that severity is the preferred construct to measure the impact of morning stiffness in patients with RA, information that is not fully captured in the RA core set.
authors: VU University Medical Center, Amsterdam, The Netherlands.
authors: M
authors: M
authors: Boers
authors: Charité University Medicine, Berlin, Germany.
authors: F
authors: F
authors: Buttgereit
authors: Schlosspark-Klinik, University Medicine, Berlin, Germany.
authors: K
authors: K
authors: Saag
authors: University of Alabama, Birmingham.
authors: R
authors: R
authors: Alten
authors: Horizon Pharma, Deerfield, Illinois.
authors: A
authors: A
authors: Grahn
authors: DPS Ltd., Cookham, UK.
authors: D
authors: D
authors: Storey
authors: Premier Research, Naperville, Illinois.
authors: P
authors: P
authors: Rice
authors: University of Bristol, Bristol, UK.
authors: J
authors: J
authors: Kirwan
mesh_terms: D000368:Aged; D000893:Anti-Inflammatory Agents / Q000627:therapeutic use; D001172:Arthritis, Rheumatoid / Q000188:drug therapy / Q000503:physiopathology*; D002940:Circadian Rhythm; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011241:Prednisone / Q000627:therapeutic use; D012720:Severity of Illness Index
chemical_list: D000893:Anti-Inflammatory Agents; D011241:Prednisone