Result of a logistic regression model to predict the start of anti-TNF therapy in AS patients
| OR, odds ratio; 95% CI, 95% confidence interval; CRP, C reactive protein; BASDAI, Bath ankylosing spondylitis disease activity index; BASFI, Bath ankylosing spondylitis functional index. *BASDAI and BASFI were considered as continuous variables in model 3. | |||
| Model 1 | |||
| Inclusion: patients with definite AS and a lag time to start anti-TNF therapy <1 month | |||
| Beta | p Value | OR (95% CI of OR) | |
| Elevated CRP | 1.089 | 0.005 | 2.972 (1.385 to 6.377) |
| Carriage of HLA-B27 | 1.473 | 0.022 | 4.361 (1.242 to 15.316) |
| BASDAI >4 | 2.051 | 0.001 | 7.774 (2.266 to 26.668) |
| Intercept | −4.800 | 0.000 | .008 |
| Model 2 | |||
| Inclusion: patients with probable AS | |||
| Beta | p Value | OR (95% CI of OR) | |
| Presence of any extra-articular manifestation | 0.778 | 0.027 | 2.177 (1.093 to 4.338) |
| BASDAI >4 | 1.806 | 0.019 | 6.084 (1.338 to 27.656) |
| Intercept | −3.388 | 0.000 | .034 |
| Model 3 | |||
| Inclusion: all probable and definite AS patients | |||
| Beta | p Value | OR (95% CI of OR) | |
| NYm_Def | 1.056 | 0.001 | 2.876 (1.533 to 5.394) |
| Elevated CRP | 0.736 | 0.000 | 2.087 (1.383 to 3.150) |
| Hip involvement | 0.635 | 0.005 | 1.887 (1.214 to 2.932) |
| HLAB27 | 0.619 | 0.019 | 1.858 (1.106 to 3.121) |
| Male sex | 0.504 | 0.016 | 1.655 (1.098 to 2.493) |
| BASDAI* | 0.228 | 0.001 | 1.256 (1.102 to 1.431) |
| BASFI* | 0.114 | 0.041 | 1.121 (1.005 to 1.251) |
| Intercept | −3.862 | 0.000 | .021 |