The longitudinal GEE analysis of the association between progression in the sacroiliitis sum score and TNFi use.
| TNFi treatment definition | Reference | β* (95% CI) |
| TNFi for ≥ 12 months in the previous 2-year interval | No TNFi for ≥ 12 months in the previous 2-year interval | -0.09 (-0.18, -0.003) |
| Any TNFi use in the previous 2-year interval | No TNFi use in the previous 2-year interval | -0.09 (-0.17, 0.002) |
| TNFi for ≥ 12 months in the current 2-year interval | No TNFi for ≥ 12 months in the current 2-year interval | -0.03 (-0.11, 0.06) |
| Any TNFi use in the current 2-year interval | No TNFi use in the current 2-year interval | 0.05 (-0.05, 0.14) |
| TNFi for ≥ 12 months in the previous and ≥ 12 months in the current 2-year interval | No TNFi for ≥ 12 months in the previous and ≥ 12 months in the current 2-year interval | -0.08 (-0.17, 0.004) |
* Parameter estimates from the multivariable models adjusted for sex, age at the beginning of the current 2-year interval, HLA-B27 positivity, symptom duration at the beginning of the current 2-year interval, time-averaged elevated CRP, time-averaged BASDAI, and time-averaged NSAID intake score in the current 2-year interval.