title: Severity and Diurnal Improvement of Morning Stiffness Independently Associate with Tenosynovitis in Patients with Rheumatoid Arthritis.
abstract: OBJECTIVE
  Although morning stiffness has long been recognized as a characteristic feature of rheumatoid arthritis (RA), it is no more included in the 2010 ACR/EULAR Classification Criteria or in the current major instruments for evaluating disease activity of RA. In this cross-sectional study, we aimed to determine the independent value and the optimal measurement of morning stiffness by clarifying the associations between morning stiffness and synovial inflammation.
  
  
  METHODS
  We enrolled 76 consecutive RA patients who underwent musculoskeletal ultrasound examination and agreed to participate in the study. In addition to asking the duration of morning stiffness, we asked patients to complete a diagram which represents the time course of their morning stiffness in the dominant hand. Based on this diagram, we calculated the severity and the diurnal improvement of morning stiffness. We also determined the activity of intra-articular synovitis in 11 joints and tenosynovitis in 8 tendons/tendon compartments in the same hand by using power Doppler (PD) ultrasound with a semiquantitative score (0-3).
  
  
  RESULTS
  For intra-articular synovitis, swollen/tender joint counts more strongly correlated with total PD scores (ρ = 0.379-0.561, p ≤ 0.001) than did any parameters of morning stiffness (ρ = 0.217-0.314, p = 0.006-0.021). For tenosynovitis, however, the severity on awakening and the improvement of morning stiffness more strongly correlated with total PD scores (ρ = 0.503-0.561, p < 0.001) than did swollen/tender joint counts (ρ = 0.276-0.388, p = 0.001-0.016). Multivariate analyses identified the severity on awakening and the improvement but not the duration of morning stiffness as factors that independently associate with the total tenosynovial PD score.
  
  
  CONCLUSIONS
  Our data demonstrate a pathophysiological link between morning stiffness and tenosynovitis and also give an insight into the optimal measurement of morning stiffness. Our data support an independent value of evaluating morning stiffness in the management of RA.
authors.affiliation: Department of Allergy and Clinical Immunology, Chiba University Hospital, Chiba, Japan.|Rheumatology Center, Matsudo City Hospital, Matsudo, Chiba, Japan.|Department of Internal Medicine, Chiba Aoba Municipal Hospital, Chiba, Japan.
authors.forename: Yoshihisa
authors.initials: Y
authors.lastname: Kobayashi
authors.affiliation: Department of Allergy and Clinical Immunology, Chiba University Hospital, Chiba, Japan.
authors.forename: Kei
authors.identifier: http://orcid.org/0000-0003-0574-9611
authors.initials: K
authors.lastname: Ikeda
authors.affiliation: Department of Allergy and Clinical Immunology, Chiba University Hospital, Chiba, Japan.|Research Center for Allergy and Clinical Immunology, Asahi General Hospital, Asahi, Chiba, Japan.
authors.forename: Takayuki
authors.initials: T
authors.lastname: Nakamura
authors.affiliation: Department of Allergy and Clinical Immunology, Chiba University Hospital, Chiba, Japan.|Department of Rheumatology, National Hospital Organization Shimoshizu Hospital, Yotsukaido, Chiba, Japan.
authors.forename: Mieko
authors.initials: M
authors.lastname: Yamagata
authors.affiliation: Department of Allergy and Clinical Immunology, Chiba University Hospital, Chiba, Japan.|Department of Rheumatology, Allergy, and Clinical Immunology, National Hospital Organization Chiba-East Hospital, Chiba, Japan.
authors.forename: Takuya
authors.initials: T
authors.lastname: Nakazawa
authors.affiliation: Department of Allergy and Clinical Immunology, Chiba University Hospital, Chiba, Japan.
authors.forename: Shigeru
authors.initials: S
authors.lastname: Tanaka
authors.affiliation: Department of Allergy and Clinical Immunology, Chiba University Hospital, Chiba, Japan.
authors.forename: Shunsuke
authors.initials: S
authors.lastname: Furuta
authors.affiliation: Rheumatology Center, Matsudo City Hospital, Matsudo, Chiba, Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Umibe
authors.affiliation: Department of Allergy and Clinical Immunology, Chiba University Hospital, Chiba, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Nakajima
mesh_terms: D001172:Arthritis, Rheumatoid / Q000150:complications* / Q000000981:diagnostic imaging / Q000503:physiopathology*; D001696:Biomechanical Phenomena; D002940:Circadian Rhythm; D005260:Female; D006225:Hand / Q000000981:diagnostic imaging; D006801:Humans; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D013717:Tenosynovitis / Q000150:complications* / Q000000981:diagnostic imaging / Q000503:physiopathology*; D018608:Ultrasonography, Doppler