What do self-administered joint counts tell us about patients with rheumatoid arthritis?

This report presents data from two sources showing that a self-administered joint count (SAJC) suitable for use in clinical settings provides information comparable with that of observer-assessed joint counts.

Patients were tested with a 1-page form containing a 40-joint mannequin on which they could mark their painful or swollen joints. The first sample of 110 patients was used to compare the SAJC with the tender or swollen joint counts (TJC or SJC) performed by a rheumatologist and to a battery of clinical and laboratory measurements. The second sample consisted of 240 rheumatoid arthritis (RA) patients enrolled in a cohort study of RA outcomes, in whom the relationship between the SAJC and health-related quality of life measures was examined.

Test-retest reliability of the SAJC was excellent (ri = 0.89), as was its agreement with the observer-assessed TJC (ri = 0.78). The SAJC was significantly correlated (P < or = 0.01) to pain on a 10-point scale (r = 0.33), the McGill Pain Questionnaire (r = 0.27), the pain subscale of the Arthritis Impact Measurement Scales (AIMS) (r = 0.32), the duration of morning stiffness (r = 0.27), and to the AIMS subscales of physical function (r = 0.20), impact (r = 0.31), and global health (r = 0.29). The SAJC was inversely related to formal education (r = -0.32), but did not correlate significantly with the modified Health Assessment Questionnaire, walking velocity, grip strength, or erythrocyte sedimentation rate. The responsiveness of the SAJC was comparable with that of other measures commonly employed to assess RA outcomes. Either the SAJC or the TJC could be included alternatively in multivariate models to explain 7 of the 8 subscales of the Medical Outcomes Study Short Form-36 (SF-36) questionnaire.

The SAJC is a reliable and responsive measure that agrees highly with the observer-assessed TJC and is significantly associated to the health-related quality of life of patients with RA. Given its low cost and ease of administration, it is suggested that SAJC be included in future studies of RA outcome in routine clinical practice.