The 27 definitions of flares for axSpA found in 38 articles
| Type of outcome | Outcome | Number of articles (% of 38 studies) | Outcome used alone or in combination, to define flares | Cut-off used (N articles concerned) |
|---|---|---|---|---|
| Composite indices | BASDAI (/10) | 17 (45) | Combination N=10 Alone N=7 | Abs. value ≥4 (N=9) Abs. value ≥3 (N=1) Abs. change 1/10 (N=2) Rel. change 80% or abs. change 2/10 (N=2) Abs. change 1.5/10 (N=1) Rel. change 60% (N=1) |
| ASDAS | 1 (2.6) | Alone | Abs. value ≥2.1 (N=1) | |
| ASAS 40 response | 1 (2.6) | Alone | Loss (N=1) | |
| Isolated patient-reported outcome | Pain (0–100 mm) | 14 (37) | Alone N=10 Combination N=4 | Abs. value ≥40 mm and increase of 30% (N=7) Abs. value ≥40 mm and increase of 30% (N=2) Rel. change 50% (N=1) Abs. change 2/10 (N=1) No cut-off (N=3) |
| Morning stiffness | 5 (13.2) | Combination N=5 | Presence (no cut-off) (N=4) Abs. value ≥30 min (N=1) | |
| Patient global assessment (0–10) | 2 (5.2) | Combination N=2 | Abs. value ≥4/10 (N=1) Rel. change ≥2/10 (N=1) | |
| NSAID intake | 1 (2.6) | Alone | Presence | |
| Physician assessment or laboratory value | Physician global assessment (0–10) | 7(18.4) | Combination N=7 | Absolute value ≥4 (N=7) |
| Physical assessment | 5 (13.2) | Combination N=5 | Restriction (N=4) Abs. change: decreased Schöber index (≥1 cm), decreased chest expansion (≥1 cm), increased fingertips to floor distance (≥5 cm) | |
| Acute phase reactants | 4 (10.4) | Combination N=4 | Presence (N=3) ESR ≥28 mm (N=1) | |
| Peripheral or extra-articular manifestation | 2 (5.2) | Combination N=2 | Presence (N=2) |
Abs: absolute; ASAS, Assessment of Spondyloarthritis; ASDAS, Ankylosing Spondylitis Disease Activity Score16; axSpA, axial spondyloarthritis; BASDAI, Bath Ankylosing Spondylitis Disease Activity Index14; ESR, erythrocyte sedimentation rate; NSAIDs, non-steroidal anti-inflammatory drugs; Rel: relative.