Table 2.
Associations for the number of anti-carbamylated protein antibody isotypes or IgG subclasses with risk factors and baseline characteristics
| Number of isotypes | 0 (n = 135) | 1 (n = 120) | 2 (n = 77) | 3 (n = 40) | Ordinal OR (95% CI) | p | |
|---|---|---|---|---|---|---|---|
| Smoking (ever), n (%) | 54 (42.9) | 48 (43.6) | 35 (48.6) | 23 (60.5) | 1.38 (0.94-2.03) | 0.099 | |
| SE positivity, n (%) | 79 (60.3) | 74 (63.2) | 57 (75.0) | 33 (86.8) | 1.91 (1.27-2.87) | 0.002* | |
| ESR (mm/h), mean ± SD | 41.0 ± 25.6 | 40.2 ± 25.1 | 43.5 ± 27.7 | 47.8 ± 26.8 | 1.01 (1.00-1.01) | 0.206 | |
| CRP (mg/L), mean ± SD | 29.0 ± 32.2 | 32.3 ± 36.4 | 29.9 ± 30.3 | 50.8 ± 47.0 | 1.01 (1.00-1.01) | 0.017 ‡ | |
| Number of IgG subclasses | 0 (n = 150) | 1 (n = 104) | 2 (n = 57) | 3 (n = 44) | 4 (n = 18) | Ordinal OR (95% CI) | p |
| Smoking (ever), n (%) | 58 (41.1) | 42 (42.4) | 30 (58.8) | 27 (65.9) | 3 (20.0) | 1.47 (1.00-2.16) | 0.051‡ |
| SE positivity, n (%) | 89 (60.5) | 65 (64.4) | 46 (80.7) | 31 (75.6) | 13 (76.5) | 1.79 (1.19-2.69) | 0.005* |
| ESR (mm/h), mean ± SD | 37.9 ± 23.2 | 37.7 ± 24.3 | 50.4 ± 31.1 | 52.3 ± 28.5 | 48.8 ± 21.6 | 1.01 (1.01-1.02) | <0.001* |
| CRP (mg/L), mean ± SD | 30.5 ± 32.9 | 28.1 ± 33.9 | 30.5 ± 34.8 | 45.4 ± 41.5 | 50.2 ± 42.9 | 1.01 (1.00-1.01) | 0.020 |
Ordinal regression analysis for the number of isotypes present and risk factors (smoking, SE positivity) or baseline parameters (ESR, CRP level)
Bold text indicates a significant difference
* Remained significant after Holm-Bonferroni correction
‡ Test of parallel lines significant
Holm-Bonferroni correction was performed for independent analyses in the whole cohort
CI confidence interval, CRP C-reactive protein, ESR erythrocyte sedimentation rate, IgG immunoglobulin G, OR odds ratio, SD standard deviation, SE shared epitope