Table 3.
Baseline predictors of ASAS20 response at three months of anti-TNF-α treatment
| Univariate analysis | Multivariate analysis | ||||
|---|---|---|---|---|---|
| OR (95% CI) | P-value | OR (95% CI) | P-value | ||
| Age (yr)†a | 0.982 (0.959 to 1.006) | 0.150 | 0.972 (0.947 to 0.998) | 0.035 | |
| Gender | Female | 1 | - | - | |
| Male | 2.166 (1.185 to 3.958) | 0.012 | 3.151 (1.580 to 6.285) | 0.001 | |
| Duration of symptoms (yr)† | 1.001 (0.976 to 1.028) | 0.914 | *** | ||
| HLA-B27 | Negative | 1 | - | - | |
| Positive | 0.779 (0.363 to 1.675) | 0.523 | *** | ||
| Peripheral arthritis | Absent | 1 | - | - | |
| Present | 2.120 (0.876 to 5.129) | 0.096 | ** | ||
| BASDAI (range 0 to 10)‡ | 0.946 (0.793 to 1.129) | 0.538 | *** | ||
| ASDAS‡ | 1.458 (0.992 to 2.144) | 0.055 | * | ||
| Physician's GDA (range 0 to 10)‡ | 1.122 (0.983 to 1.282) | 0.089 | ** | ||
| Patient's GDA (range 0 to 10)‡a | 1.029 (0.882 to 1.201) | 0.714 | ** | ||
| ESR (mm/h)‡a | 1.016 (1.000 to 1.032) | 0.049 | 1.023 (1.005 to 1.041) | 0.014 | |
| CRP (mg/l)‡ | 1.021 (1.003 to 1.040) | 0.025 | * | ||
| BASFI (range 0 to 10)‡ | 0.939 (0.816 to 1.081) | 0.382 | *** | ||
| Chest expansion (cm)‡a | 1.081 (0.948 to 1.233) | 0.243 | ** | ||
| Modified Schober test (cm)‡ | 1.026 (0.861 to 1.224) | 0.773 | *** | ||
| Occiput to wall distance (cm)‡a | 0.981 (0.942 to 1.022) | 0.364 | ** | ||
| Lateral lumbar flexion L (cm)‡ | 1.027 (0.965 to 1.092) | 0.402 | *** | ||
| Lateral lumbar flexion R (cm)‡ | 1.029 (0.968 to 1.094) | 0.352 | *** | ||
| TNF-α blocking agent | ETA | 1 | - | - | |
| IFX | 2.045 (0.780 to 5.364) | 0.146 | ** | ||
| ADA | 0.938 (0.476 to 1.846) | 0.852 | ** | ||
See Table 1 for definitions.
OR refers to the risk of achieving ASAS20 response: † per year; ‡ per 1 grade or 1 point.
a Significant difference (P < 0.05) between men and women at baseline.
* CRP and ASDAS were not selected during forward conditional logistic regression due to the strong correlation with ESR (ESR and CRP: ρ = 0.669, P = 0.000; ESR and ASDAS: ρ = 0.412, P = 0.000). Although, higher CRP level (OR: 1.024, 95% CI: 1.004 to 1.044) and higher ASDAS level (OR: 1.728, 95% CI: 1.126 to 2.652) were also significant predictors of ASAS20 response at three months in the presence of age and gender.
** The variable was not selected during multivariate regression analysis (P ≥0.05).
*** The variable was not tested in multivariate regression analysis because of a P-value > 0.3 in univariate regression analysis and no significant difference between men and women at baseline.