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Table 5 Clinical characteristics and HLA-B27 test results of patients with nonradiographic axial spondyloarthritis across geographic regions

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

  Africa (n = 33) Europe (n = 88) Asia (n = 140) p Value
Laboratory-confirmed SpA (HLA-B27)     0.062
 Positive, n (%) 15 (45.45 %) 56 (63.64 %) 61 (43.57 %)  
 Negative, n (%) 6 (18.18 %) 10 (11.36 %) 37 (26.43 %)  
 Results not available, n (%) 12 (36.36 %) 22 (25.00 %) 42 (30.00 %)  
Laboratory-confirmed SpA (excluding missing) (HLA-B27)     0.019
 Positive, n (%) 15 (71.43 %) 56 (84.85 %) 61 (62.24 %)  
 Negative, n (%) 6 (28.57 %) 10 (15.15 %) 37 (37.76 %)  
Family history of SpA     0.231
 Yes, n (%) 9 (27.27 %) 18 (20.45 %) 43 (30.71 %)  
 No, n (%) 22 (66.67 %) 67 (76.14 %) 86 (61.43 %)  
 Results not available, n (%) 2 (6.06 %) 3 (3.41 %) 11 (7.86 %)  
Family history of SpA (excluding missing)     0.125
 Yes, n (%) 9 (29.03 %) 18 (21.18 %) 43 (33.33 %)  
 No, n (%) 22 (70.97 %) 67 (78.82 %) 86 (66.67 %)  
NSAID response     0.264
 Positive, n (%) 22 (66.67 %) 64 (72.73 %) 93 (66.43 %)  
 Negative, n (%) 7 (21.21 %) 22 (25.00 %) 42 (30.00 %)  
 Results not available, n (%) 4 (12.12 %) 2 (2.27 %) 5 (3.57 %)  
Most recent CRP level     0.214
 Not elevated (<3.5 mg/L), n (%) 10 (30.30 %) 21 (23.86 %) 37 (26.43 %)  
 Elevated (≥3.5 mg/L), n (%) 18 (54.55 %) 55 (62.50 %) 80 (57.14 %)  
 Results not available, n (%) 5 (15.15 %) 12 (13.64 %) 23 (16.43 %)  
Most recent CRP level (excluding missing)     0.104
 Not elevated (<3.5 mg/L), n (%) 10 (35.71 %) 21 (27.63 %) 37 (31.62 %)  
 Elevated (≥3.5 mg/L), n (%) 18 (64.29 %) 55 (72.37 %) 80 (68.38 %)  
Most recent ESR level     <0.001
 Not elevated (<28 mm/h), n (%) 20 (60.61 %) 66 (75.00 %) 69 (49.29 %)  
 Elevated (≥28 mm/h), n (%) 9 (27.27 %) 17 (19.32 %) 66 (47.14 %)  
 Results not available, n (%) 4 (12.12 %) 5 (5.68 %) 5 (3.57 %)  
Most recent ESR level (excluding missing)     <0.001
 Not elevated (<28 mm/h), n (%) 20 (68.97 %) 66 (79.52 %) 69 (51.11 %)  
 Elevated (≥28 mm/h), n (%) 9 (31.03 %) 17 (20.48 %) 66 (48.89 %)  
  1. Abbreviations: CRP C-reactive protein, ESR erythrocyte sedimentation rate, HLA-B27 human leukocyte antigen B27, NSAID nonsteroidal anti-inflammatory drug, SpA spondyloarthritis
  2. The p values represent the omnibus statistical comparison of percentages (or means) across regions based on the chi-square values