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Table 5 Baseline predictors of anti-TNF-α treatment discontinuation

From: Baseline predictors of response and discontinuation of tumor necrosis factor-alpha blocking therapy in ankylosing spondylitis: a prospective longitudinal observational cohort study

   Univariate analysis Multivariate analysis
   HR (95% CI) P-value HR (95% CI) P-value
Age (yr)†a   0.994 (0.975 to 1.014) 0.561   **
Gender Female 1 -   -
  Male 0.503 (0.321 to 0.787) 0.003 0.406 (0.251 to 0.657) 0.000
Duration of symptoms (yr)†   0.981 (0.959 to 1.002) 0.082   **
HLA-B27 Negative 1 -   -
  Positive 0.823 (0.468 to 1.448) 0.500   ***
Peripheral arthritis Absent 1 -   -
  Present 0.382 (0.176 to 0.830) 0.015 0.320 (0.144 to 0.712) 0.005
BASDAI (range 0 to 10)‡b   1.162 (1.016 to 1.329) 0.028 1.225 (1.053 to 1.424) 0.008
ASDAS‡b   1.005 (0.759 to 1.330) 0.974   **
Physician's GDA (range 0 to 10)‡b   0.907 (0.816 to 1.008) 0.070   **
Patient's GDA (range 0 to 10)‡a   1.075 (0.958 to 1.208) 0.219   **
ESR (mm/h)‡a   0.987 (0.974 to 0.999) 0.039 0.983 (0.969 to 0.997) 0.018
CRP (mg/l)‡b   0.986 (0.972 to 1.000) 0.049   *
BASFI (range 0 to 10)‡   1.045 (0.935 to 1.168) 0.438   ***
Chest expansion (cm)‡a   0.986 (0.903 to 1.076) 0.753   **
Modified Schober test (cm)‡   1.189 (1.036 to 1.365) 0.014   **
Occiput to wall distance (cm)‡a   0.971 (0.938 to 1.006) 0.971   **
Lateral lumbar flexion L (cm)‡   1.018 (0.973 to 1.066) 0.434   ***
Lateral lumbar flexion R (cm)‡   1.016 (0.971 to 1.062) 0.498   ***
TNF-α blocking agent ETA 1 -   -
  IFX 0.847 (0.441 to 1.627) 0.618   ***
  ADA 1.334 (0.769 to 2.314) 0.305   ***
  1. See Table 1 for definitions.
  2. HR refers to the risk of anti-TNF-α treatment discontinuation: † per year; ‡ per 1 grade or 1 point.
  3. a Significant difference (P < 0.05) between men and women at baseline.
  4. b Significant difference (P < 0.05) between patients with peripheral arthritis (defined as at least one swollen joint) and only axial disease at baseline.
  5. * CRP was not selected during forward conditional logistic regression due to the strong correlation with ESR (ρ = 0.669, P = 0.000) and the significant difference in CRP level between patients with and without peripheral arthritis (median 17 vs. 12, P = 0.014). Although, lower CRP level (HR: 0.984, 95% CI: 0.969 to 0.999) was also a significant predictor of treatment discontinuation in the presence of gender and BASDAI.
  6. ** The variable was not selected during multivariate regression analysis (P ≥0.05).
  7. *** 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.