Table 5

Baseline predictors of anti-TNF-α treatment discontinuation

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

***

See Table 1 for definitions.

HR refers to the risk of anti-TNF-α treatment discontinuation: † per year; ‡ per 1 grade or 1 point.

^a Significant difference (P < 0.05) between men and women at baseline.

^b Significant difference (P < 0.05) between patients with peripheral arthritis (defined as at least one swollen joint) and only axial disease at baseline.

* 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.

** 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