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Abstract
Background A significant number of rheumatoid arthritis (RA) patients can reach low disease activity (LDA) by using TNF-inhibitors (TNF-i), but this therapy can cause serious side-effects and is expensive. Therefore it could be expedient to stop in case of LDA, unless a relapse can be predicted. Ultrasonography of joints seems to be a predictor in this respect in smaller studies.
The Dutch POET (Potential Optimalisation of Expediency of TNF-i (TNF-inhibitor)) study, is a multicenter randomized prospective cohort study investigating if in patients with RA with LDA on TNF-i and conventional DMARD, the TNF-i can be stopped. Patients were randomized to continue or stop TNF-i. Part of this study is the POET-ultrasonography (US) study.
Objectives To investigate whether US, at the time of stopping TNF-i in RA patients with LDA, is an additive predictor for flare besides clinical data.
Methods Data were analysed of 251 patients who stopped TNF-i in the POET study. Participating patients had RA according to ACR 1987 criteria, >6 months a DAS28 <3.2 (LDA) and treatment with TNF-i >1 year next to a conventional DMARD, with no dose change 6 months prior to randomisation. Nineteen trained ultrasonographers performed at baseline of the study US (with different US machines) of 20 joints: MCP 1–5 dorsal and volar, wrist and MTP 2–5 dorsal aspect, all bilaterally. The joints were graded on grayscale (GS; 0–3) and power Doppler (PD; 0–3). US signs of arthritis were defined as GS>1 and/or PD>0. Trial visits were performed every 3 months during 12 months and intercurrently when flare was suspected. Flare was defined as DAS28 >3.2 and at least >0.6 increase compared to the baseline DAS28. Univariate and multivariate Cox-regression was performed guided by clinical factors described in the literature and US.
Results The Kaplan Meier curve for patients with US signs of arthritis in one or more joints shows greater/higher risk of flare and shorter relapse-free period compared to the curve for patients without US signs of arthritis, p= (figure). At multivariate analysis (table), correcting for potentially clinical predictors, US detected arthritis stayed a statistically significant predictor of flare; HR 1.69; 95% CI 1.11 to 2.53. The predictive value of US seems not that strong that it can be used in individual patients.
Conclusions The presence of US arthritis is associated with an earlier flare and a higher flare rate compared to those with negative US taking into account demographic and clinical patient characteristics.
Disclosure of Interest F. Lamers-Karnebeek Grant/research support from: Abbvie, J. Luime: None declared, P. van Riel: None declared, J. Jacobs: None declared, T. Jansen: None declared