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.

Arends et al. Arthritis Research & Therapy 2011 13:R94   doi:10.1186/ar3369

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