Reevaluation of the role of duration of morning stiffness in the assessment of rheumatoid arthritis activity.
OBJECTIVE
To evaluate the utility of the duration of morning stiffness (MS), as a patient-reported outcome (PRO), in assessing rheumatoid arthritis (RA) disease activity.


METHODS
We acquired information on 5439 patients in QUEST-RA, an international database of patients with RA evaluated by a standard protocol. MS duration was assessed from time of waking to time of maximal improvement. Ability of MS duration to differentiate RA activity states, based on Disease Activity Score (DAS)28, was assessed by analysis of variance; and a receiver-operating characteristic (ROC) curve was plotted for discriminating clinically active (DAS28 > 3.2) from less active (DAS28 <or= 3.2) RA. Mixed-effect analysis of covariance (ANCOVA) models were used to assess the utility of adding MS duration to Routine Assessment of Patient Index Data (RAPID)3, a PRO index based on physical function, pain, and general health (GH), in predicting the 3-variable DAS28 (DAS28v3).


RESULTS
MS duration had moderate correlation (r = 0.41-0.48) with pain, Health Assessment Questionnaire, and GH; and weak correlation (r = 0.23-0.39) with joint counts and erythrocyte sedimentation rate. MS duration differed significantly among patients with different RA activity (p < 0.001). The area under the ROC curve of 0.74 (95% CI 0.72-0.75) showed moderate ability of MS duration to differentiate clinically active from less active RA. ANCOVA showed significant interactive effects between RAPID3 and the MS duration categories (p = 0.0005) in predicting DAS28v3. The effect of MS was found to be clinically important in patients with the low RAPID3 scores (< 6) in whom the presence of MS may indicate clinically active disease (DAS28v3 > 3.2).


CONCLUSIONS
MS duration has a moderate correlation with RA disease activity. Assessment of MS duration may be clinically helpful in patients with low RAPID3 scores.
Khan
Nasim A
NA
University of Arkansas for Medical Sciences,Central Arkansas Veterans Healthcare System, Little Rock, Arkansas 72205, USA. nakhan@uams.edu
Yazici
Yusuf
Y
Calvo-Alen
Jaime
J
Dadoniene
Jolanta
J
Gossec
Laure
L
Hansen
Troels M
TM
Huisman
Margriet
M
Kallikorm
Riina
R
Muller
Raili
R
Liveborn
Margareth
M
Oding
Rolf
R
Luchikhina
Elena
E
Naranjo
Antonio
A
Rexhepi
Sylejman
S
Taylor
Peter
P
Tlustochowich
Witold
W
Tsirogianni
Afrodite
A
Sokka
Tuulikki
T
D000368:Aged; D001172:Arthritis, Rheumatoid / Q000473:pathology / Q000503:physiopathology; D016208:Databases, Factual; D005260:Female; D006801:Humans; D007596:Joints / Q000473:pathology / Q000503:physiopathology; D008875:Middle Aged; D012372:ROC Curve; D012720:Severity of Illness Index