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Table 1 Baseline characteristics of all undifferentiated arthritis patients and those who progress to RA after 1 year and those who do not

From: What is the additional value of MRI of the foot to the hand in undifferentiated arthritis to predict rheumatoid arthritis development?

 

UA at baseline, N = 123

RA after 1 year, N = 64

No RA after 1 year, N = 59

P value

Clinical parameters

 Age, mean (SD)

57 (18)

59 (19)

55 (16)

0.29

 Female, n (%)

73 (59)

40 (63)

33 (56)

0.46

 Symptom duration, in weeks, median (IQR)

9 (4–27)

12 (6–30)

8 (3–21)

0.048

 Swollen joint count, median (IQR)

2 (1–4)

3 (2–5)

1 (1–3)

< 0.001

 Presence of swollen joint foot, n (%)

25 (20)

12 (20)

13 (22)

0.65

 Presence of swollen joint hand, n (%)

66 (54)

40 (63)

26 (44)

0.041

 Presence of tender joint foot, n (%)

32 (26)

17 (27)

15 (25)

0.89

 Presence of tender joint hand, n (%)

71 (58)

44 (69)

27 (46)

0.010

 CRP, mg/L, median (IQR)

5 (3–14)

6 (3–16)

3 (3–9)

0.035

 ACPA positive, n (%)

6 (5)

4 (7)

2 (3)

0.44

 RF positive, n (%)

8 (7)

5 (8)

3 (5)

0.53

MRI features

 MTP 1–5

  Tenosynovitis, mean (SD)

0.6 (1.3)

0.8 (1.4)

0.4 (1.1)

0.075

  Synovitis, mean (SD)

0.7 (1.0)

0.7 (1.0)

0.7 (1.1)

0.69

  BME, mean (SD)

0.8 (1.4)

0.6 (0.9)

1.0 (1.7)

0.50

 MCP 2–5

  Tenosynovitis, mean (SD)

1.4 (2.0)

2.0 (2.3)

0.8 (1.2)

< 0.001

  Synovitis, mean (SD)

1.6 (1.8)

2.1 (1.9)

1.1 (1.5)

0.001

  BME, mean (SD)

0.6 (1.5)

0.6 (1.3)

0.7 (1.6)

0.85

 Wrist

  Tenosynovitis, mean (SD)

2.4 (3.1)

3.2 (3.5)

1.5 (2.4)

0.006

  Synovitis, mean (SD)

1.9 (2.1)

2.4 (2.3)

1.5 (1.8)

0.023

  BME, mean (SD)

3.0 (5.2)

3.5 (5.8)

2.5 (4.5)

0.57

  1. Sixty-six swollen joint counts were performed. For the presence of a swollen or tender foot, the presence of a swollen or tender MTP joint was taken, respectively. For the presence of swollen or tender hand, the presence of a swollen or tender MCP or wrist joint was taken, respectively. Differences between patients with and without progression to RA after 1 year were tested with chi-square test, t test or Mann-Whitney U test as appropriate
  2. UA undifferentiated arthritis, SD standard deviation, IQR interquartile range, CRP C-reactive protein, RF rheumatoid factor, ACPA anti-citrullinated protein antibody, MCP metacarpophalangeal joint, MTP metatarsophalangeal joint, BME bone marrow edema