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Table 2 Demographic characteristics of nonradiographic axial spondyloarthritis, ankylosing spondylitis, and other inflammatory back pain patients

From: The prevalence and clinical characteristics of nonradiographic axial spondyloarthritis among patients with inflammatory back pain in rheumatology practices: a multinational, multicenter study

 

Total (N = 914)

nr-axSpA (n = 266)

AS (n = 491)

Other IBP (n = 157)

p Value

Sex

    

<0.001

 Male, n (%)

588 (64.33 %)

169 (63.53 %)

350 (71.28 %)

69 (43.95 %)

 

  95 % CI

(61.22–67.44)

(57.74–69.33)

(67.27–75.29)

(36.17–51.73)

 

 Female, n (%)

326 (35.67 %)

97 (36.47 %)

141 (28.72 %)

88 (56.05 %)

 

  95 % CI

(32.56–38.78)

(30.67–42.26)

(24.71–32.73)

(48.27–63.83)

 

Sex

    

<0.001

 Male, n (row %)

588 (100.00 %)

169 (28.75 %)

350 (59.52 %)

69 (11.73 %)

 

  95 % CI

 

(25.08–32.41)

(55.54–63.50)

(9.13–14.34)

 

 Female, n (row %)

326 (100.00 %)

97 (29.75 %)

141 (43.25 %)

88 (26.99 %)

 

  95 % CI

 

(24.78–34.73)

(37.86–48.64)

(22.17–31.82)

 

Age, years, mean ± SD

38.68 ± 12.02

34.75 ± 10.03

39.03 ± 11.38

44.26 ± 14.48

<0.001

Race/ethnicity

    

<0.001

 White, n (%)

596 (65.21 %)

148 (55.64 %)

335 (68.23 %)

113 (71.97 %)

 

  95 % CI

(62.11–68.30)

(49.66–61.62)

(64.10–72.35)

(64.94–79.01)

 

 Asian, n (%)

116 (12.69 %)

55 (20.68 %)

55 (11.20 %)

6 (3.82 %)

 

  95 % CI

(10.53–14.85)

(15.80–25.55)

(8.41–14.00)

(0.82–6.83)

 

 Black, n (%)

12 (1.31 %)

2 (0.75 %)

2 (0.41 %)

8 (5.10 %)

 

  95 % CI

(0.57–2.05)

(0.00–1.79)

(0.00–0.97)

(1.65–8.54)

 

 Unknown, n (%)

190 (20.79 %)

61 (22.93 %)

99 (20.16 %)

30 (19.11 %)

 

  95 % CI

(18.15–23.42)

(17.87–27.99)

(16.61–23.72)

(12.95–25.27)

 

BMI category

    

0.024

 Underweight, n (%)

55 (6.02 %)

12 (4.51 %)

38 (7.74 %)

5 (3.18 %)

 

  95 % CI

(4.47–7.56)

(2.01–7.01)

(5.37–10.11)

(0.43–5.94)

 

 Normal weight, n (%)

455 (49.78 %)

150 (56.39 %)

236 (48.07 %)

69 (43.95 %)

 

  95 % CI

(46.53–53.03)

(50.42–62.36)

(43.64–52.49)

(36.17–51.73)

 

 Overweight, n (%)

279 (30.53 %)

78 (29.32 %)

146 (29.74 %)

55 (35.03 %)

 

  95 % CI

(27.53–33.52)

(23.84–34.8)

(25.68–33.79)

(27.56–42.51)

 

 Obese, n (%)

121 (13.24 %)

24 (9.02 %)

70 (14.26 %)

27 (17.20 %)

 

  95 % CI

(11.04–15.44)

(5.57–12.47)

(11.16–17.36)

(11.28–23.11)

 

 Unknown, n (%)

4 (0.44 %)

2 (0.75 %)

1 (0.20 %)

1 (0.64 %)

 

  95 % CI

(0.01–0.87)

(0.00–1.79)

(0.00–0.60)

(0.00–1.88)

 

Years since CLBP presentation

    

<0.001

 Number of patients

808

232

435

141

 

 Mean ± SD, years

9.09 ± 9.07

6.32 ± 7.61

10.91 ± 9.37

8.05 ± 9.10

 

Age of IBP onset

    

<0.001

 Number of patients

908

264

488

156

 

 Mean ± SD, years

28.8 ± 9.7

27.8 ± 7.3

27.0 ± 7.7

36.2 ± 14.2

 
  1. Abbreviations: AS ankylosing spondylitis, BMI body mass index, CLBP chronic low back pain, CRF case report form, IBP inflammatory back pain, nr-axSpA nonradiographic axial spondyloarthritis
  2. Broad race categories (white vs. black vs. Asian vs. unknown) were created on the basis of physician-reported patient ethnicity: white = Indian, Indo-Aryan, Dravidian, Bengali, Arab, Iranian, white, Jewish, Azeri, Mestizo, Amerindian, Berber; black = black, mulatto, mulato, zambo, black African, colored; Asian = Han Chinese, non-Han Chinese, Taiwanese, Chinese, aborigine, Malay, indigenous, mongoloid, Asian; unknown = other or missing
  3. The p values represent the omnibus statistical comparison of percentages (or means) across IBP groups based on the chi-square (or F-test) values
  4. “Other IBP” refers to patients who did not meet the Assessment of SpondyloArthritis international Society classification criteria for axial spondyloarthritis
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Arthritis Research & Therapy

ISSN: 1478-6362

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