To examine whether low disease activity criteria using the disease activity score (DAS28) can be applied to identify a reasonably large number of patients with stable low disease activity of rheumatoid arthritis (RA) over a six month period, with the ultimate intention of including these patients in a substitution based, shared care model. Additionally, to assess the reliability of the DAS28 for selecting patients with stable disease from an outpatient population.
Patients regularly seen at the rheumatology outpatient department of the university hospital Maastricht, were invited for assessment of the stability of their RA. The shared care model was intended to provide care to patients with stable, low disease activity of RA by nurse specialists. For this, patients underwent assessments using the DAS28 criteria at entry and three and six months later. Test-retest reliability was assessed for composing measures as well as for the DAS28.
Of the 97 outpatients included, one third (31 patients) did not complete the study. Patients with missing data were older and assessed their disease activity as greater than patients with complete data. Applying the low disease activity criteria to assess stability over a period of six months (DAS28(T0)</=3.2 and DAS28(T6)-DAS28(T0)</=1.2) resulted in identification of 22/56 (39%) patients with stable, low disease activity of RA. A good similarity score (intraclass correlation coefficient=0.82) for the DAS28 was found.
The low disease activity criteria using the DAS28 can be used to select patients with stable, low disease activity of RA from a rheumatic outpatient population.