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Table 1 Baseline characteristics of patients with disease relapse (“relapsers”) or stable disease activity (“nonrelapsers”) during 1 year of follow-up

From: Calprotectin strongly and independently predicts relapse in rheumatoid arthritis and polyarticular psoriatic arthritis patients treated with tumor necrosis factor inhibitors: a 1-year prospective cohort study

Characteristic Total (n = 95) Nonrelapsers (n = 83) Relapsers (n = 12) p value
Age (years) 57 (50–66) 57 (50–66) 57 (48–63.5) 0.614
Female, n (%) 61 (64.2%) 53 (63.9%) 8 (66.7%) 1.000
Disease duration (years) 15 (9–21) 15 (9–21) 14.5 (7.5–24.5) 0.831
Diagnosis, n (%)     0.215
 Psoriatic arthritis 51 (53,7%) 47 (56.6%) 4 (33.3%)  
 Rheumatoid arthritis 44 (46.3%) 36 (43,4%) 8 (66.7%)  
Time to csDMARD (months) 25.6 (5.1–62.2) 24.4 (5.5–62.2) 32.6 (5.1–92.3) 0.911
Time to bDMARD (months) 98.5 (36.9–165.9) 98.5 (38.8–160.9) 95.9 (33.6225.9) 0.823
Time-to-remission/LDA (months) 3.27 (2.13–4.3) 3.07 (1.9–3.97) 20.4 (16.8–24.3) < 0.001
Time-in-remission/LDA (months) 58.7 (26.7–86.6) 60.1 (27.6–88.0) 25.0 (9.4–59.3) 0.027
Calprotectin (μg/mL) 1.66 (0.69–2.68) 1.44 (0.62–2.34) 6.01 (5.01–6.44) < 0.001
CRP (mg/dL) 0.10 (0.04–0.26) 0.09 (0.03–0.22) 0.17 (0.04–0.52) 0.388
ESR (mm) 10 (7–18) 10 (7–16) 14.5 (8–21.5) 0.225
Albumin (g/L) 42 (31–48) 43 (31–48) 31 (31–47) 0.210
Biologic treatment, n (%)     0.843
 Adalimumab 34 (35.8%) 30 (36.1%) 4 (33.3%)  
 Etanercept 44 (46.3%) 39 (47.0%) 5 (41.7%)  
 Infliximab 17 (17.9%) 14 (16.9%) 3 (25.0%)  
Biological treatment duration (months) 61.6 (30.8–91.4) 63.2 (31.8–92.7) 39.9 (25.1–61.2) 0.136
Reduced dose of biologicsa, n (%) 45 (47.4%) 40 (48.2%) 5 (41.7%) 0.672
Monotherapy, n (%) 45 (47.4%) 42 (50.6%) 3 (25.0%) 0.127
Concomitant steroids, n (%) 18 (18.9%) 13 (15.7%) 5 (41.7%) 0.047
Global TNFi trough serum levels (μg/mL) 2.20 (1.07–6.26) 2.70 (1.18–6.83) 1.14 (0.73–1.52) 0.001
Adalimumab (μg/mL) 7.04 (2.69–9.40) 7.19 (5.78–9.88) 1.28 (0.73–1.59) 0.009
Etanercept (μg/mL) 1.45 (1.00–2.25) 1.52 (0.92–2.32) 1.24 (1.20–1.54) 0.698
Infliximab (μg/mL) 2.94 (0.86–3.26) 3.16 (1.92–4.84) 0 (0–1.05) 0.023
DAS28-ESR 2.03 (1.68–2.6) 1.99 (1.67–2.52) 2.43 (1.89–2.74) 0.145
Remission, n (%) 72 (75.8%) 65 (78.3%) 7 (58.3%) 0.175
Low disease activity, n (%) 23 (24.2%) 18 (21.7%) 5 (41.7%) 0.127
SDAI 6.03 (2.2–6.26) 6.02 (2.11–6.22) 6.18 (4.53–6.96) 0.087
CDAI 6 (2–6) 6 (2–6) 6 (4–6.5) 0.220
Global ultrasound score 8 (3–13) 8 (3–13) 17.5 (9.5–31) 0.041
PD score 1 (0–2) 1 (0–2) 5.5 (2.5–10) < 0.001
SH score 7 (3–11) 6 (3–10) 8.5 (5–12) 0.210
PDUS, n (%) 50 (52.6%) 38 (45.8%) 8 (66.6%) < 0.001
Number of joints with PDUS 1 (0–2) 1 (0–2) 3.5 (2.5–5) < 0.001
UdAS, n (%) 29 (30.5%) 17 (20.5%) 7 (58.3%) < 0.001
  1. Values are shown as median (interquartile range) unless otherwise stated
  2. Significant p values are shown in bold typeface
  3. bDMARD biologic disease-modifying antirheumatic drug, CDAI Clinical Disease Activity Index, CRP C-reactive protein, csDMARD conventional synthetic disease-modifying antirheumatic drug, DAS28 28-joint Disease Activity Score, ESR erythrocyte sedimentation rate, LDA low disease activity, PD power Doppler, PDUS power Doppler ultrasound synovitis, SH synovial hypertrophy, SDAI Simplified Disease Activity Index, TNFi tumor necrosis factor inhibitors, UdAS ultrasound-defined active synovitis
  4. aTreatment regimen with a lower amount of the drug or longer intervals of administration than those recommended in the package insert for each product