Table 4.
Sensitivity analyses of the association between exposure to TNFi and radiographic progression 2 years later (multivariable models)*
|
mSASSS, β (95% CI) |
|
|---|---|
| 6‐month window between imaging and the clinical visit | |
| Model 1 (adjusted for ASDAS) (n = 266) | −0.76 (−1.28, −0.25)† |
| Model 2 (adjusted for ASDAS) (n = 249) | −0.88 (−1.52, −0.23)† |
| Main analysis after PS adjustment | |
| Model 1 (PS population, no PS adjustment) | NA |
| Model 1 (PS population, PS adjusted) | NA |
| Model 2 (PS population, no PS adjustment) (n = 301) | −0.87 (−1.45, −0.28)† |
| Model 2 (PS population, PS adjusted) (n = 301) | −0.80 (−1.37, −0.22)† |
| Alternative definitions of exposure to TNFi | |
| Model 1 | |
| TNFi between visits (yes/no) (n = 300) | −0.37 (−0.86, 0.11) |
| Duration of TNFi between visits (years) (n = 300) | −0.25 (−0.52, 0.01) |
| Proportion of time between visits with TNFi (0–100%) (n = 300) | |
| Continuous variable (0–100%) | −0.51 (−1.04, 0.03) |
| Binary variable (>50 versus ≤50%) | −0.42 (−0.94, 0.11) |
| Long versus short continuous TNFi exposure (≥4 years versus <4 years) (n = 313) | −0.31 (−0.85, 0.22) |
| Model 2 | |
| TNFi between visits (yes/no) (n = 293) | −0.45 (−1.02, 0.11) |
| Duration of TNFi between visits (years) (n = 293) | −0.20 (−0.52, 0.11) |
| Proportion of time between visits with TNFi (0–100%) (n = 293) | −0.41 (−1.04, 0.22) |
| Proportion of time between visits with TNFi (>50% versus ≤50%) (n = 293) | −0.23 (−0.81, 0.35) |
| Continuous TNFi (≥4 years versus <4 years) (n = 306) | −0.33 (−0.89, 0.24) |
Model 1 was a multivariable multilevel longitudinal generalized estimating equation (GEE) model with individual modified Stoke Ankylosing Spondylitis Spine Score (mSASSS) per reader as the outcome, adjusted for the correlation of mSASSS within each reader. Model 2 was a multivariable longitudinal GEE model with the average of the 2 readers’ mSASSS scores as the outcome. Both models were adjusted for mSASSS at the start of the interval, Ankylosing Spondylitis Disease Activity Score (ASDAS), symptom duration (years), sex, HLA–B27, and the number of tumor necrosis factor inhibitors (TNFi) used before inclusion. 95% CI = 95% confidence interval; PS = propensity score; NA = not applicable.
Significant association.