Background/Purpose : Morning stiffness may not be specifically queried by rheumatologists in the course of their regular interactions with rheumatoid arthritis (RA) patients.  This analysis investigated whether morning stiffness was correlated with measures of disease activity.

Methods:  Data from the Corrona RA Registry included RA patients who initiated a new therapy: non-biologic or biologic DMARD, whether as monotherapy or in combination, and remained on treatment for ≥ 90 days. Patients were evaluated at initiation, 1 and 2 years after initiation and time of last visit. Correlations of measures of disease activity with presence and change in morning stiffness were modeled at the patients’ last Corrona visit between January 2013 and February 2014. For patients with ≥ one visit during this interval, propensity score (PS) trimming of the top and bottom 5% was used to obtain comparable populations with and without morning stiffness. Thus data from 90% of RA patients (5379 subjects) were utilized to examine the association of measures of disease activity: remission (CDAI ≤2.8); low disease activity (2.822) with presence/absence of morning stiffness, after PS trimming at time of last visit.

Results : At baseline those with morning stiffness (n=9688) were less likely to be working, more likely to have received biologic therapy, Medicaid insurance, and to have higher measures of disease activity than those without (n=2865): CDAI high: 34.1 vs 10.3%; remission/low: 31.6 vs 66.3%, p<0.0001. At one year after initiation of treatment, these differences persisted (with morning stiffness (n=6148) without (n=2597), including statistically significantly higher mHAQ scores: 0.5 ± 0.5 vs 0.1 ±0.3, p<0.0001; more reporting disabled work status: 21.7 vs 5.2%, p<0.0001 and CDAI high: 21.7 vs 5.2%; remission/low: 48.0 vs 80.2% p<0.0001. These differences persisted even after 2 years of follow-up (with morning stiffness (n=4466) without (n=1895): mHAQ scores unchanged; disabled: 29.2 vs 9.4%; CDAI high:19.3 vs 3.9%; remission/low: 51.4 vs 82.0, all p<0.0001. At time of last Corrona visit, higher CDAI, mHAQ and patient reported fatigue were significantly associated with presence of morning stiffness and increased persistence of morning stiffness (Figure 1).

Conclusion : In this registry analysis, presence and persistence of morning stiffness consistently reflected higher disease activity associated with more impairment of physical function and self reported work disability.