Table 2.
Comparisons of IgA anti-CD74, HLA-B27, smoking and demographics between patients with radiographic axial spondyloarthritis and matched controls
| Characteristic |
r-axSpA
(n = 155) |
Controls
(n = 151) |
P-value |
|---|---|---|---|
| Sex, n (%) | |||
| Women | 48 (31.0) | 48 (31.8) | 0.9 |
| Men | 107 (69.0) | 103 (68.2) | |
| Age, mean (s.d.), years | |||
| All | 55.5 (11.45) | 53.0 (9.0) | <0.001 |
| Women | 57.7 (10.6) | 53.7 (8.9) | <0.001 |
| Men | 54.5 (11.7) | 52.6 (9.0) | <0.001 |
| Ever smoker, n (%) | 71 (45.8) | 59 (39.3)a | 0.25 |
| HLA-B27 positive, n (%) | |||
| All | 152 (98.1) | 30 (25.6)b | <0.001 |
| Women | 47 (97.9) | 11 (28.9) | <0.001 |
| Men | 105 (98.1) | 19 (24.0) | <0.001 |
| IgA anti-CD74 | |||
| All, median (IQR), U/ml | 12.9 (7.9–17.9) | 10.9 (7.2–14.6) | 0.003 |
| mean (s.d.), U/ml | 14.9 (10.1) | 12.7 (7.8) | |
| Women, median (IQR), U/ml | 13.2 (8.4–20.4) | 9.6 (6.6–13.9) | 0.011 |
| Men, median (IQR), U/ml | 12.9 (8.7–16.6) | 11.5 (8.1–15.9) | 0.076 |
| IgA anti-CD74+ (cut-off 20 U/ml), n (%) | |||
| All | 36 (23.2) | 15 (9.9) | 0.002 |
| Women | 13 (27.1) | 5 (10.4) | 0.036 |
| Men | 23 (21.5) | 10 (9.7) | 0.019 |
| r-axSpA | Controls | |||
|---|---|---|---|---|
| HLA-B27 status | B27+ | B27− | B27+ | B27− |
| IgA anti-CD74+ | 36 | 0 | 1 | 13 |
| IgA anti-CD74− | 116 | 3 | 29 | 74 |
| Total | 152 | 3 | 30 | 87 |
| P-valuec | 0.45 | 0.11 | ||
| IgA anti-CD74, median (IQR), U/ml | 13.0 (8.7–18.8) | 11.8 (6.6–12.2) | 11.0 (7.2–14.2) | 11.4 (7.6–18.9) |
| P-value | 0.34 | 0.38 | ||
a
One missing. bHLA-B27 was analysed in 117 controls, 38 women and 79 men. cFisher’s exact test. IQR: interquartile range; r-axSpA; radiographic axial spondyloarthritis.