Longitudinal relationship between ASDAS and radiographic damage in different strata
| Stratification for | Stratum analysed | Multivariable regression models (autoregressive and time-lagged) ß (95%CI)* |
|---|---|---|
| Gender | ASDAS in males (n=129) | 0.98 (0.56 to 1.39) |
| ASDAS in females (n=54)† | −0.06 (−0.40 to 0.27) | |
| Symptom duration‡ | ASDAS in symptom duration <18 years (n=92) | 0.84 (0.42 to 1.26) |
| ASDAS in symptom duration ≥18 years (n=80) | 0.16 (−0.22 to 0.54) | |
| Gender and symptom duration‡ | ASDAS in women, symptom duration <18 years (n=24) | 0.21 (0.03 to 0.38) |
| ASDAS in women, symptom duration ≥18 years (n=29) | −0.06 (−0.63 to 0.51) | |
| ASDAS in men, symptom duration <18 years (n=68) | 0.94 (0.43 to 1.45) | |
| ASDAS in men, symptom duration ≥18 years (N=51) | 0.36 (−0.12 to 0.84) |
*Results refer to different multivariable models. Stratifications were made due to significant interactions. The ß indicates the progression in mSASSS per unit increase in ASDAS per 2 years. In italic are the strata in which there is a significant effect of disease activity (as measured by the ASDAS) on radiographic damage (as measured by the mSASSS).
†One patient had a missing in one of the items of the ASDAS (BASDAI question 3) and therefore ASDAS could not be calculated.
‡Symptom duration was not available for 12 patients who could therefore not be included in this stratified analysis.
ASDAS, Ankylosing Spondylitis Disease Activity Score; BASDAI, Bath AS Disease Activity Index; mSASSS, modified Stoke Ankylosing Spondylitis Spine Score.