Comparison of different definitions to classify remission and sustained remission: 1 year TEMPO results

Abstract

Objective: To assess methods to calculate achieving and sustaining remission in a double blind randomised trial in patients with RA who received etanercept, methotrexate, or an etanercept/methotrexate combination.

Methods: Remission was defined as DAS <1.6, DAS28 <2.6, and ACR70 response. Sustaining remission was analysed in three ways: (a) analysis of sustained DAS remission, DAS28 remission, or ACR70 response continuously for 6 months; (b) analysis of sustained remission appraised through a continuity rewarded scoring system, which is the weighted sum of all intervals in the study in which patients are in DAS or DAS28 remission; or (c) longitudinal modelling of remission odds using generalised estimating equations.

Results: Significantly more patients treated with the etanercept/methotrexate combination reached DAS remission (37%) than those treated with either methotrexate (14%) or etanercept (18%) alone (p<0.01). Results for DAS28 and for the ACR70 response were similar. Agreement between DAS remission and DAS28 remission was good, but agreement between either of these and the ACR70 response was less. Patients in DAS or DAS28 remission had a lower level of disease activity (fewer active joints, lower ESR) than those achieving ACR70 response; the converse was seen using pain VAS. The three methods were comparable for sustainability of remission and showed significant advantage for combination therapy, which increased the number and durability of remission periods.

Conclusions: DAS and DAS28 remission results were similar for assessing achieving and sustaining remission in RA, frequently differing from patients classified as ACR70 responders. The three methods of examining duration of remission produced comparable results.

Figure 1

Tender joint count distribution among patients in DAS remission, DAS28 remission, and fulfilling ACR70 response. Mean (SD) tender joint counts for DAS remission, DAS28 remission, and ACR70 responders were 0.4 (1.2), 1.2 (2.4), and 1.8 (2.5), respectively. Medians (25%–75% interquartile range (IQR)) for DAS remission, DAS28 remission, and ACR70 responders were 0 (0–0), 0 (0–2), and 1 (0–3), respectively.

Figure 4

Pain visual analogue scale (VAS) for patients in DAS remission, DAS28 remission and fulfilling ACR70 response, ordered from the lowest to the highest value and expressed as the cumulative probability. Means (SD) for DAS remission, DAS28 remission, and ACR70 responders were 11.5 (12.3), 11.8 (11.3), and 9.0 (8.6), respectively. Medians (25%–75% IQR) for DAS remission, DAS28 remission, and ACR70 responders were 8.0 (2–17), 10 (2–18), and 8 (2–13), respectively.

Figure 2

Swollen joint count distribution among patients in DAS remission, DAS28 remission, and fulfilling ACR70 response. Mean (SD) swollen joint count for DAS remission, DAS28 remission, and ACR70 responders were 0.8 (1.6), 0.8 (1.6), and 1.1 (1.8), respectively. Medians (25%–75% IQR) for DAS remission, DAS28 remission, and ACR70 responders were 0 (0–1), 0 (0–1), and 0 (0–2), respectively.

Figure 3

Erythrocyte sedimentation rate (ESR) for individual patients in DAS remission, DAS28 remission, and fulfilling ACR70 response, ordered from the lowest to the highest value and expressed as the cumulative probability. Means (SD) for DAS remission, DAS28 remission, and ACR70 responders were 13.6 (10.5), 11.2 (7.3), and 17.7 (14.4), respectively. Medians (25%–75% IQR) for DAS remission, DAS28 remission, and ACR70 responders were 11 (6–18), 10 (6–16), and 14 (8–22), respectively.