Descriptive statistics at baseline. Results are presented as median (interquartile range), mean ± SD, or percentage.
| Characteristic | Total, n = 62 | RA, n = 35 | PsA, n = 27 |
|---|---|---|---|
| Demographic and clinical measures | |||
| Age, yrs*** | 53 (28–74) | 56 (35–74) | 44 (28–66) |
| Female:male, no. | 39:23 | 24:11 | 15:12 |
| Disease duration, yrs | 7 (0.2–40) | 7 (1–40) | 8 (0.2–34) |
| Rheumatoid factor, n (%) | 26 (42) | 26 (74) | 0 (0) |
| Use of corticosteroids, n (%) | 12 (19.3) | 8 (22.8) | 4 (14.8) |
| BMI, kg/cm2 | 27.7 ± 5.9 | 26.2 ± 6.4 | 29.6 ± 4.8 |
| ESR, mm/h** | 25.8 ± 23.9 | 34.5 ± 25.2 | 15.1 ± 17.3 |
| CRP, mg/dl; normal < 5** | 23.5 ± 27.6 | 32.1 ± 32.9 | 12.7 ± 12.6 |
| DAS28-CRP† | 5.67 (4.68–6.33) | 5.89 (4.76–6.41) | 5.44 (4.62–6.15) |
| Fatigue, 0–10 scale# | 6 (5–8) | 6 (4.5–8.0) | 6 (4.9–7.0) |
| GVAS, 0–100 mm VAS | 50 (40–70) | 60 (45–80) | 50 (40–61) |
| HAQ, 0–3 scale | 1.13 (0.63–1.63) | 1.38 (0.63–1.75) | 1.06 (0.59–1.50) |
| Pain, 0–10 scale†† | 6.0 (3.5–8.0) | 6 (4.5–8.0) | 5.5 (3.0–7.0) |
| TJC, 0–28 joints | 10 (5–16) | 9 (4.5–16.0) | 13 (5–19) |
| SJC, 0–28 joints | 11.0 (5.5–15.8) | 12 (7.5–16) | 9 (4–14) |
| Stiffness, min | 60 (15–120) | 60 (20–120) | 45 (8.8–60) |
| Bone turnover markers | |||
| Bone ALP, μg/l* | 12.6 ± 5.6 | 10.8 ± 3.6 | 14.7 ± 6.8 |
| PINP, μg/l | 49.2 ± 22.9 | 47.1 ± 19.0 | 51.8 ± 27.2 |
| OC[1–49], μg/l | 12.0 ± 6.5 | 10.9 ± 4.8 | 13.3 ± 8.1 |
| CTX-I, μg/l | 0.444 ± 0.260 | 0.444 ± 0.234 | 0.445 ± 0.290 |
| NTX-I, nmolBCE/mmol Cr | 47.5 ± 31.9 | 47.8 ± 24.8 | 47.1 ± 39.7 |
| fDPD, nmol/mmol Cr | 8.29 ± 4.41 | 9.05 ± 4.79 | 7.34 ± 3.77 |
| BMD measurements, g/cm2 | |||
| Hand BMD | 0.350 ± 0.052 | 0.335 ± 0.057 | 0.360 ± 0.047 |
| PIP periarticular BMD | 0.285 ± 0.051 | 0.277 ± 0.054 | 0.294 ± 0.043 |
| MCP periarticular BMD | 0.305 ± 0.51 | 0.297 ± 0.054 | 0.316 ± 0.040 |
| Total hip BMD | 0.954 ± 0.138 | 0.936 ± 0.141 | 0.974 ± 0.135 |
| Lumbar spine BMD | 0.997 ± 0.133 | 0.989 ± 0.137 | 1.006 ± 0.131 |
Differences between RA and PsA:
↵* p < 0.05;
↵** p < 0.01;
↵*** p < 0.001.
↵† DAS28-CRP: 28-joint Disease Activity Score using the C-reactive protein-based formula (www.das-score.nl).
↵# Fatigue scale: 0 = no fatigue to 10 = fatigue as bad as it could be.
↵†† Pain scale: 0 = no pain to 10 = pain as bad as it could be. BMI: body mass index; ESR: erythrocyte sedimentation rate; GVAS: global visual analog scale (0 = worst imaginable health state to 100 = best imaginable health state); HAQ: Health Assessment Questionnaire scale (0 = no difficulty to 3 = unable to perform activity); TJC: tender joint count; SJC: swollen joint count; serum bone ALP: bone-specific alkaline phosphatase; serum PINP: procollagen type-I N-propeptide; serum OC[1–49]: intact osteocalcin; serum CTX-I: C-terminal cross-linking telopeptide of type-I collagen; urine NTX-I: N-terminal cross-linking telopeptide of type-I collagen; urine fDPD: free deoxypyridinoline crosslinks; BMD: bone mineral density; PIP: proximal interphalangeal joints; MCP: metacarpophalangeal joints.