Table 2.
Calprotectin, disease activity, ultrasound assessment and tumour necrosis factor inhibitor trough serum levels according to diagnosis
| Patient characteristics | RA (n = 42) | PsA (n = 50) | ||
|---|---|---|---|---|
| PDUS-negative (n = 15) | PDUS-positive (n = 27) | PDUS-negative (n = 34) | PDUS-positive (n = 16) | |
| Female sex, n (%) | 11 (73.3) | 23 (85.2) | 15 (44.1) | 10 (62.5)a |
| Age, years, median (range) | 62 (49–78) | 64 (30–81) | 53 (33–77) | 55 (40–72) |
| Disease duration, years, median (range) | 13 (8–28) | 17 (2–44) | 13.5 (1–28) | 16 (3–36) |
| Concomitant csDMARD, n (%) | 11 (73.3) | 21 (77.8) | 11 (32.4) | 4 (25) |
| Reduced dose, n (%) | 4 (26.7) | 8 (29.6) | 21 (61.8) | 9 (56.3) |
| Calprotectin, μg/ml, median (range) | 1.44 (0.2–2.4) | 2.95 (0.2–5.5)a | 0.70 (0.06–3.7) | 2.36 (0.9–4.6)b |
| CRP, mg/dl, median (range) | 0.07 (0.02–0.1) | 0.30 (0.01–1.4)a | 0.08 (0.01–0.6) | 0.09 (0.01–0.3) |
| ESR, mm/h, median (range) | 10 (2–24) | 13 (2–43) | 8 (2–29) | 13 (4–32)a |
| SJC, median (range) | 0 (0–1) | 0 (0–3) | 0 (0–1) | 0 (0) |
| TJC, median (range) | 0 (0–1) | 0 (0–2) | 0 (0–1) | 0 (0–1) |
| DAS28-ESR, median (range) | 2.08 (1.5–2.6) | 2.62 (1.3–3.2)a | 1.67 (1–2.7) | 2.15 (1.1–3.1)a |
| Remission based on DAS28-ESR, n (%) | 13 (86.7) | 14 (51.9)b | 9 (90) | 6 (75)a |
| Low disease activity based on DAS28-ESR, n (%) | 2 (13.3) | 13 (48.1)b | 1 (10) | 2 (25) |
| SDAI, median (range) | 6.02 (2–8) | 6.26 (2–11)a | 5.10 (2–8) | 6.04 (2–8.3) |
| CDAI, median (range) | 6 (2–8) | 6 (2–11) | 5 (2–8) | 6 (2–8) |
| ADA trough serum levels, μg/ml, median (range) | 8.39 (4.2–12) | 1.68 (0.6–12)a | 6.95 (4.1–12) | 0.88 (0.2–9.8)a |
| ETN trough serum levels, μg/ml, median (range) | 2.54 (0.2–4.7) | 0.98 (0.7–2.3)a | 1.38 (01–3.5) | 0.91 (0.6–1.6)a |
| IFX trough serum levels, μg/ml, median (range) | 8.39 (4.2–12) | 1.68 (0.6–12)a | 3.21 (0.7–7.7) | 2.86 (0.1–6.5) |
Abbreviations: ADA adalimumab, CDAI Clinical Disease Activity Index, CRP C-reactive protein, csDMARD conventional synthetic disease-modifying anti-rheumatic drug, DAS28-ESR 28-joint Disease Activity Score based on erythrocyte sedimentation rate, ESR erythrocyte sedimentation rate, ETN etanercept, IFX infliximab, PDUS power Doppler ultrasound, PsA psoriatic arthritis, RA rheumatoid arthritis, SDAI Simple Disease Activity Index, SJC swollen joint count, TJC tender joint count
a p < 0.05
b p < 0.001