Baseline clinical characteristics of patients with psoriatic arthritis stratified by presence of axial involvement. Values are mean ± SD or n (%).
| Characteristics* | Overall, n = 1530 | With Axial Involvement, n = 192 | Without Axial Involvement, n = 1338 | P |
|---|---|---|---|---|
| Enthesitis | 316 (20.7) | 59 (30.7) | 257 (19.2) | < 0.001 |
| SPARCC Enthesitis Index, 1–16 | 3.8 ± 3.3 | 5.1 ± 3.9 | 3.4 ± 3.0 | 0.001 |
| Dactylitis | 194 (12.7) | 19 (9.9) | 175 (13.1) | 0.22 |
| Dactylitis count, 1–20 | 2.4 ± 1.8 | 3.3 ± 2.5 | 2.3 ± 1.7 | 0.08 |
| BSA, % affected | 5.7 ± 11.3 | 6.7 ± 12.5 | 5.5 ± 11.1 | 0.19 |
| BSA, categorical | 0.005 | |||
| Mild disease, 0 to < 3% | 969 (67.2) | 104 (57.5) | 865 (68.5) | |
| Moderate disease, ≥ 3 to ≤ 10% | 296 (20.5) | 53 (29.3) | 243 (19.3) | |
| Severe disease, > 10% | 178 (12.3) | 24 (13.3) | 154 (12.2) | |
| MDA† | 554 (44.2) | 46 (30.1) | 508 (46.2) | < 0.001 |
| CDAI | 11.6 ± 8.7 | 12.4 ± 9.3 | 11.6 ± 8.6 | 0.25 |
| Tender joint count, 68 | 3.7 ± 7.8 | 5.2 ± 9.2 | 3.5 ± 7.5 | 0.004 |
| Swollen joint count, 66 | 2.0 ± 4.1 | 2.3 ± 4.9 | 2.0 ± 3.9 | 0.37 |
| Nail psoriasis, VAS 0–100 | 7.1 ± 15.1 | 11.4 ± 18.8 | 6.5 ± 14.4 | < 0.001 |
| BASDAI, 0–10 | 3.6 ± 2.6 | 4.7 ± 2.5 | 3.5 ± 2.5 | < 0.001 |
| BASFI, 0–10 | 2.7 ± 2.6 | 3.8 ± 2.8 | 2.5 ± 2.5 | < 0.001 |
| DAS28-CRP | 2.7 ± 1.0 | 2.8 ± 1.1 | 2.7 ± 1.0 | 0.48 |
| ASDAS-CRP | 2.0 ± 0.8 | 2.2 ± 0.9 | 1.9 ± 0.8 | 0.001 |
| CRP, mg/l | 2.6 ± 7.3 | 4.1 ± 11.2 | 2.4 ± 6.5 | 0.02 |
| ESR, mm/h | 15.5 ± 16.1 | 16.5 ± 17.4 | 15.4 ± 15.9 | 0.51 |
↵* All values were calculated based on available data. All variables had < 20% missing data except for CRP (n = 934) and ESR (n = 926).
↵† MDA was defined as “Yes” if a patient met ≥ 5 of the 7 following categories20: tender joint count ≤ 1, swollen joint count ≤ 1, BSA ≤ 3%, patient pain VAS ≤ 15, patient global activity VAS ≤ 20, HAQ ≤ 0.5, tender entheseal points ≤ 1. ASDAS: Ankylosing Spondylitis Disease Activity Score; BASDAI: Bath Ankylosing Spondylitis Disease Activity Index; BASFI: Bath Ankylosing Spondylitis Functional Index; BSA: body surface area; CDAI: Clinical Disease Activity Index; CRP: C-reactive protein; DAS28: 28-joint Disease Activity Score; ESR: erythrocyte sedimentation rate; HAQ: Health Assessment Questionnaire; MDA: minimal disease activity; SPARCC: Spondyloarthritis Research Consortium of Canada; VAS: visual analog scale.