Morning stiffness may result from a different mechanism of action than joint swelling or elevated ESR

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Morning Stiffness in Early Rheumatoid Arthritis (RA) is Correlated

Significantly with Self-Report of Functional Disability and Pain and

Correlated Weakly with Joint Swelling and Erythrocyte Sedimentation Rate

(ESR): Implications for Possible Mechanisms

Purpose: To determine the level of morning stiffness in a cohort of

early RA patients, using a self-report questionnaire, and to analyze

correlations of these levels with patient self-report scores for

functional disability, pain, fatigue, joint count, ESR, number of

symptoms, and patient and physician global assessments, in view of the

status of morning stiffness as a traditional sign of inflammation, a

classification criterion for RA, and an inclusion criterion for most

recent RA clinical trials.

Methods: 305 U.S. patients with early RA since 1998 consented to

participate in an observational longitudinal study of long-term outcomes

of patients with early RA. The baseline evaluation included a

multidimensional health assessment questionnaire (MDHAQ) to assess

functional disability, pain, and global status, morning stiffness,

fatigue, and number of symptoms, as well as tender and swollen joint

counts, ESR, physician global assessment, and radiographs of the hands

and feet. Spearman rank correlation coefficients of morning stiffness

with other measures and regressions were computed.

Results: Of the 305 patients, 76% were female, 89% Caucasian, 71%

rheumatoid factor (RF) positive. Median disease duration was 20 months,

and age 53 years. 295 patients had morning stiffness data. 61 patients

reported no morning stiffness, and 234 reported a mean of 88 minutes of

morning stiffness. Mean morning stiffness for all patients was 70 minutes.

Spearman rank correlations of morning stiffness indicated significant

associations with scores for MDHAQ, pain, fatigue, patient global,

physician global, and tender joint count in the range of 0.37 - 0.50,

all p<0.001. Correlations with swollen joint count, ESR, and age were

statistically significant, but much lower,. In regression analysis,

MDHAQ and pain scores were significant and independently associated with

morning stiffness, while swollen joint count, and ESR were not

significantly associated with morning stiffness.

Conclusion: In this group of early RA patients, morning stiffness was

correlated at low levels with common markers of inflammation, ESR and

swollen joint counts, while higher correlations were seen with

functional disability, pain, fatigue, tender joint and patient and

physician global assessment of disease activity. These observations

suggest consideration that morning stiffness may result from a different

mechanism of action than joint swelling or elevation of the ESR.

Yusuf Yazici1, Tuulikki Sokka2, Theodore Pincus2. 1Brooklyn Heights

Arthritis Associates, New York, NY; 2Vanderbilt University Medical

Center, Nashville, TN