Background Spondyloarthritis (SpA) activity varies with time and treatment, but to date no clear definition of a flare of the disease is available.
Objectives The aim of this study was to evaluate thresholds of disease activity variations using validated composite indexes
Methods SpA patients fulfilling ASAS criteria and prospectively followed with at least two visits were evaluated using BASDAI, ASDAS-CRP and ASDAS-ESR. Patients and physician answered at each visit the question: “do you consider your SpA in a state of flare ?”. Variations of BASDAI and ASDAS between visits were assessed and associated to the change of perception of a flare (yes/no). ROC curves were built to assess thresholds of variation in BASDAI end ASDAS associated with the change Flare: no to yes between visits.
Results The patients were issued from a prospective series of 250 SpA. 99 situations with at least 2 visits were analyzed. The main characteristics of this cohort were: 67% men, mean age 45±12 years; disease duration: 16±10 y; 84% HLA-B27 positive; purely axial SpA: 81%; PASS at baseline: 56%; mean CRP: 8.6±13.5 mg/l. Mean BASDAI and ASDAS-CRP at baseline were 4.3±2.2 and 2.5±1.1 respectively. The kappa coefficient of agreement between patient and physician for considering a flare was 0.68. The main results of the ROC curves are reported in the table:
Conclusions According to these results, an increase from a non-flare state of at least 2.1 units in BASDAI, 0.8 units in ASDAS-ESR or 1.3 units in ASDA-CRP is associated to (and may define) a flare, as considered by the patient and the physician.
This is the first study assessing, in current practice, thresholds of variation of activity score associated with a flare in SpA. This may help physicians in the evaluation and management of the patients with SpA.
Disclosure of Interest None declared