Table 3.
Factor identification.
| Item | Factor 1 “Peripheral disease” | Factor 2 “Axial disease” | Factor 3 “Uveitis” |
|---|---|---|---|
| 1. Active joint count | 0.41 | −0.37 | 0.15 |
| 2. Active enthesitis count | 0.42 | 0.24 | 0.17 |
| 3. Patient assessment of pain (past week) | 0.49 | −0.08 | −0.14 |
| 4. ESR or CRP related to JSpA activity | 0.27 | −0.58 | −0.15 |
| 5. Morning stiffness | 0.48 | 0.07 | −0.01 |
| 6. Clinical sacroiliitis | 0.32 | 0.64 | 0.08 |
| 7. Uveitis | 0.02 | 0.02 | 0.63 |
| 8. Back mobility | 0.08 | 0.21 | −0.71 |
Legend. Items of the JSpADA index loaded on three primary factors after PCA. Items 1-5 load on factor 1 “Peripheral disease”, items 6 and 8 load on factor 2 “Axial disease” and item 7 loads significantly on factor 3 “Uveitis”.