Background Patients with rheumatoid arthritis (RA) often experience stiffness of joints, with considerable impact on functional capacity. While morning stiffness (MS) has been excluded from the core set due to poor measurement properties, recent qualitative research from our group suggests stiffness is an important symptom to patients when striving for remission (in preparation).
Objectives This systematic review aims to identify available patient-oriented measurement instruments that have been developed to assess stiffness in patients with rheumatoid arthritis.
Methods To identify measurement instruments for patient reported stiffness, an extensive Pubmed search was undertaken to identify existing, feasible measurement instruments or subscales of existing instruments for patient perceived stiffness, that have been developed or used within RA research. Eligible studies included reports of patient reported stiffness in RA patients 1) comparing stiffness as an outcome in relation to other core set disease activity measures, 2) aiming to develop a patient reported tool to measure stiffness, or 3) comparing two different tools to measure aspects of stiffness.
Results Of 788 titles, 13 relevant studies were included in this review. Six questionnaires with stiffness as a subdomain were identified; 6 studies compared two or more stiffness scales with each other and 8 studies correlated stiffness to a core set measure. No specific stiffness questionnaires were identified. Measures of stiffness generally showed good correlation with core set measures (especially pain and function), and moderate correlation with each other, but did not adequately discriminate RA from non-inflammatory conditions or osteoarthritis. Compared to duration, severity of stiffness was superior in terms of sensitivity to change over time, responsiveness to therapy, differentiation between active and inactive disease and inter-patient variation. Two studies investigated whether MS levels differed between patients with active and inactive disease. One showed a significant relation between MS duration and disease activity levels (1); in the other the number of patients with current MS did not differ between active and inactive RA, but patients with active disease experienced significantly higher severity scores (2).
Conclusions Measurement of stiffness in RA has been limited to the assessment of either morning stiffness duration or severity of (morning) stiffness. These two measures correlate moderately well with each other and other core set measures. Severity outperforms duration of MS, but data on measurement properties of MS in the spectrum of low disease activity or remission is scare.
Khan et al, 2009
Hazes et al, 1993
Disclosure of Interest L. van Tuyl Grant/research support from: Pfizer (unconditional grant), W. Lems: None Declared, M. Boers: None Declared