Background Axial Spondyloarthritis (axSpA) is characterized by alternated periods of flares and remission. This fluctuating disease activity varies from one patient to another in terms of symptom intensity and flares frequency and may lead to poor outcomes.
Objectives The objective of this study was to assess the frequency of patient reported flares, and the validity of this concept through their related factors and through the relation between time spent in flare and disease activity assessed by BASDAI.
Methods This was a cross-sectional study in 2004 from the Canadian FOllow-up Research Cohort of Ankylosing SpondyliTis (FORCAST). Participants had definite Ankylosing spondylitis (AS) according to modified New-York criteria. Current flare status (yes/no), number of flares over the past 3 months and average duration of a flare (in weeks) were assessed by self-report. Disease activity was assessed by BASDAI and BASFI was also collected. Only patients with complete data for flare questions were included in this analysis. Descriptive statistics were performed and univariate and multivariate logistic regression analysis compared patients with at least 1 flare over 3 months to those without flares, for disease activity, treatment, and demographic characteristics. Association between disease activity and percentage of time spent in flare was assessed by Spearman correlation.
Results 234 patients were analyzed including 169 (72.2%) men, with a mean age of 45.5 (±11.8) years and a mean disease duration of 21.7 (±11.7) years. Their mean BASDAI and BASFI (0–10) were respectively 4.4 (±2.3) and 3.4 (±2.6); 55 (23.5%) were taking conventional disease modifying drugs and 18 (7.69%) were taking antiTNF. Overall, 117 (50%) of patients were currently in flare and 174 (74.3%) reported at least one past flare. In those with flares, the median number of flares per patient over 3 months was 3 (interquartile range, 2, 4.5), their median duration was 2 weeks (1, 3) and the median time spent in flare was 25% (0, 66.7) over 3 months (figure). In multivariate analyses patients flaring had a significantly higher BASDAI (OR=1.84, p<0.001), were more often treated by NSAIDs (OR=6.65, p=0.02) and less often by anti-TNF (OR=0.16, p<0.01) than the no flare group. Patients reporting only past flares also had higher BASDAI (OR=1.59, p<0.01) and were less often treated by anti-TNF (OR=0.14, p=0.01). There was a significant correlation between the percentage of time spent in flare and the BASDAI score (r=0.58, p-value <0.0001).
Conclusions In this cross-sectional study assessment of patients in 2004 little treated with anti-TNF, flares were very frequent and long; patients reported spending a mean of 25% of their time in flare. As expected patients reporting at least one recent flare had higher disease activity, were more likely to be taking NSAIDs and were less likely to be taking anti-TNF. The time spent in flare was well-correlated with BASDAI. These results indicate the validity of the concept of flares as assessed by a single question in axSpA.
Stone MA, et al. Rheumatology (Oxford) 2008;47:1213–8
Gossec, et al. Ann Rheum 2016 in press
Disclosure of Interest None declared