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Open Access Research article

Good correlation between changes in objective and subjective signs of inflammation in patients with short- but not long duration of axial spondyloarthritis treated with tumor necrosis factor-blockers

Anja Weiß1*, In-Ho Song2, Hildrun Haibel2, Joachim Listing1 and Joachim Sieper12

Author Affiliations

1 German Rheumatism Research Center, Charitéplatz 1, 10117 Berlin, Germany

2 Medical Department I, Rheumatology, Charité Medical University, Campus Benjamin Franklin, Berlin, Germany

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Arthritis Research & Therapy 2014, 16:R35  doi:10.1186/ar4464

Published: 30 January 2014

Abstract

Introduction

The aim of this study was to investigate the influence of symptom duration on treatment response and on the correlation between improvements in patient reported outcomes (PRO) and objective inflammation in patients with axial spondylarthritis (SpA) treated with etanercept (ETA) or adalimumab (ADA).

Methods

Data from 112 patients with axial SpA originally enrolled in two randomized controlled clinical trials were pooled and analyzed after one year of treatment with ETA (n = 66) or ADA (n = 46). Patients with <4 years and ≥4 years of disease were compared for improvement in Bath Ankylosing Spondylitis Disease Activity Index (BASDAI), Bath Ankylosing Spondylitis Functional Index (BASFI), Ankylosing Spondylitis Disease Activity Score (ASDAS), C-reactive protein (CRP) and magnetic resonance imaging (MRI) score for sacroiliac joints (SIJ).

Results

Patients with <4 years of disease showed a significantly better improvement than longer diseased patients in BASDAI (3.2 (95% confidence interval (CI): 2.7 to 3.7) vs. 1.7 (1.1 to 2.2)), BASFI, BASMI and ASDAS (1.6 (1.4 to 1.8) vs. 0.9 (0.7 to 1.1)). The change in BASDAI showed a significant correlation with the change in SIJ score (Spearman’s rank correlation coefficient (rho) = 0.37, P = 0.01) and the change in CRP (rho = 0.45, P = 0.001) in patients with <4 years of disease. For long diseased patients this correlation was poor and did not achieve statistical significance (rho = 0.13, P = 0.46; rho = 0.22, P = 0.13 respectively).

Conclusion

The low correlation between change of PROs and change of objective signs of inflammation seen in axial SpA patients with longer symptom duration treated with tumor necrosis factor-blocker seems to indicate that inflammation is not the only cause of the patients’ symptoms, while inflammation seems to be the major cause in short diseased patients.

Trial registration

Clinical Trials.gov NCT00844142 (Trial 1); NCT00235105 (Trial 2)