Domains, instruments and questionnaires included in SpA-Net
| Domain | Reported by | Instrument | Interval (minimum)* |
| Demographic characteristics | Patient | Questionnaire (education, marital state, employment, alcohol, smoking) | 1 year |
| Work, productivity | Patient | WPAI41 | 6 months |
| Quality of life, health state | Patient | SF-36,42 EQ-5D,43 ASAS Health Index44 | 1 month (SF-36), 6 months (EQ-5D, ASAS Health Index) |
| Physical function | Patient | BASFI,45 HAQ-S46 | 6 months |
| Patient global | Patient | NRS (global disease activity last week) | 1 month |
| Fatigue | Patient | Fatigue question of BASDAI47 | Every visit |
| Pain | Patient | VAS | 1 month |
| Experience with care | Patient | Modified PREM48 | 1 year |
| Medical history, comorbidity | Physician | NA | Updated every visit |
| Medication use | Physician | NA | Updated every visit |
| Adverse events | Physician, patient | NA | Updated every visit |
| SpA manifestations | Physician | Checklist: inflammatory back pain, peripheral arthritis, enthesitis, dactylitis, psoriasis, uveitis, IBD, elevated CRP, NSAID response, recent GI or urogenital infection, positive family history, sacroiliitis on X-ray/MRI, HLA-B27 status | Updated every visit |
| Disease activity | Physician, patient | ASDAS,49 BASDAI,47 CRP, ESR | Every visit |
| Physician global | Physician | VAS (disease activity) | Every visit |
| Spinal mobility | Physician | Chest expansion, occiput to wall, modified Schober, cervical rotation, lateral spinal flexion | On indication |
| Peripheral symptoms | Physician | SJC66, TJC68, presence and location of dactylitis, presence and location of enthesitis in 65 sites | Every visit |
| Skin/Nail involvement | Physician | Body surface area, presence of nail psoriasis | On indication |
| Laboratory results | Physician | Haemoglobin, white blood cell count, platelet count liver/renal function | On indication |
*Minimum interval between assessments of the domain. Visits to the rheumatologist are not predefined, but scheduled according to the opinion of the care provider. Consequently, the interval between assessments of domains can vary among patients but will never be shorter than the minimum interval reported here.
ASAS, Assessment of SpondyloArthritis International Society;ASDAS, Ankylosing Spondylitis Disease Activity Score;BASDAI, Bath Ankylosing Spondylitis Disease Activity Index;BASFI, Bath Ankylosing Spondylitis Functional Index;CRP, C reactive protein;EQ-5D, EuroQoL-5D;ESR, erythrocyte sedimentation ratio;GI, gastrointestinal;HAQ-S, Health Assessment Questionnaire for Spondyloarthropathies;HLA-B27, human leucocyte antigen B27;IBD, inflammatory bowel disease;NA, not applicable; NRS, Numerical Rating Scale;NSAID, non-steroidal anti-inflammatory drug;PREM, patient-reported experience measure;SF-36, 36-Item Short Form Health Survey;SJC, swollen joint count;SpA, spondyloarthritis;TJC, tender joint count;VAS, Visual Analogue Scale;WPAI, Work Productivity and Activity Impairment.