Table 2 Baseline characteristics of patients in the DIP joint OA progression cohort, stratified by progression of DIP joint OA at follow-up.

From: Association of BMI with radiographic incidence and progression of distal interphalangeal joint osteoarthritis in rheumatoid arthritis patients

Characteristics

No DIP joint OA progression

(n = 475)

DIP joint OA progression

(n = 1006)

P

Age, mean ± SD years

61.1 ± 10.6

60.0 ± 9.7

0.051

Sex, (% of patients)

  

0.046

Female

348 (73.3)

786 (78.1)

 

Male

127 (26.7)

220 (21.9)

 

BMI, mean ± SD kg/m2

25.8 ± 4.6

26.0 ± 4.6

0.473

BMI category

  

0.829

Healthy Weight (18.5–24.9 kg/m2)

181 (48.7)

363 (47.6)

 

Overweight (25.0–29.9 kg/m2)

125 (33.6)

270 (35.4)

 

Obesity (≥ 30.0 kg/m2)

66 (17.7)

130 (17.0)

 

ACPA, (% of patients))

  

0.620

Negative

89 (36.6)

172 (34.5)

 

Positive

154 (63.4)

327 (65.5)

 

RF, (% of patients)

  

0.648

Negative

111 (24.0)

223 (22.8)

 

Positive

351 (76.0)

756 (77.2)

 

Double negative serology (RF– / ACPA–), (% of patients)

  

0.752

No

370 (90.2)

786 (91.0)

 

Yes

40 (9.8)

78 (9.0)

 

ESR, median [IQR] mm/hour

18.0 [10.0, 33.0]

20.0 [10.0, 34.0]

0.491

Disease duration since first symptoms, median [IQR] years

8.0 [3.2, 15.5]

6.5 [2.4, 14.2]

0.010

Tender joints (range 0–28), median [IQR] number

3 [0, 9]

4 [1, 9]

0.393

Swollen joints (range 0–28), median [IQR] number

4 [1, 9]

5 [1, 9]

0.173

Patient-assessed general health, mean ± SD VAS score

4.2 ± 2.8

4.0 ± 2.7

0.225

Summed % of erosive joint surface destruction in 8 MCP joints, (% of patients)

  

0.067

0

78 (22.2)

254 (29.5)

 

10 – 20

144 (40.9)

307 (35.7)

 

30 – 70

70 (19.9)

163 (19.0)

 

80 – 800

60 (17.0)

136 (15.8)

 

Radiographic observation time, median (IQR) years

4.0 [2.7, 5.9]

5.7 [3.7, 8.2]

 < 0.001

Summed K/L grade in 8 joints at baseline, median [IQR] number

8 [4, 13]

8 [5, 12]

0.317

Summed JSN grade in 8 joints at baseline, median [IQR] number

1 [0, 3]

1 [0, 3]

0.561

Summed osteophytes grade in 8 joints at baseline, median [IQR] number

3 [1, 5]

2 [1, 14]

0.105

Sclerosis (%)

  

0.079

No

253 (53.3)

485 (48.2)

 

Yes

222 (46.7)

521 (51.8)

 

Erosion (%)

  

0.0499

No

420 (88.4)

923 (91.7)

 

Yes

55 (11.6)

83 (8.3)

 
  1. Between-group comparisons were carried out using chi-square tests, Student’s t-tests, or Wilcoxon-Mann–Whitney tests, and based on complete cases. Progression was defined as an increase of ≥ 1 in the Kellgren/Lawrence (K/L) grade in any of the 8 distal interphalangeal (DIP) joints from baseline to follow-up in patients with DIP joint osteoarthritis (OA). ACPA = anti–citrullinated protein antibody; BMI = body mass index; ESR = erythrocyte sedimentation rate; IQR = interquartile range; JSN: joint space narrowing; MCP = metacarpophalangeal; RF = rheumatoid factor; VAS = visual analog scale.
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