Associations in database without parenteral GC bridging with primary (upper 3) and secondary (bottom 3) outcomes
| Initial GC dose (effect per additional mg) | Duration of induction schedule (effect per additional week) | |
| GC status after bridging* | ||
| 1 month | 1.00 (0.99 to 1.02) | Omitted |
| 3 months | 1.02 (0.99 to 1.05) | 1.09 (1.04 to 1.15) |
| 6 months | 1.03 (1.00 to 1.07) | 1.06 (0.97 to 1.16) |
| 12 months | 1.04 (1.02 to 1.06) | 1.08 (1.01 to 1.16) |
| 18 months | 1.04 (1.01 to 1.06) | 1.14 (1.05 to 1.24) |
| Mean cumulative GC dose at (mg) | ||
| 6 months | 41 (30 to 53) | 76 (46 to 105) |
| 12 months | 25 (15 to 35) | 73 (35 to 111) |
| 18 months | 67 (63 to 71) | 124 (117 to 131) |
| ≥3 months continuous GC use† (% yes) within | ||
| 12 months | 1.02 (0.99 to 1.05) | 1.07 (1.00 to 1.14) |
| 24 months | 1.03 (1.00 to 1.05) | 1.04 (0.99 to 1.10) |
| Flare after‡ | ||
| First GC bridging stop attempt (%) | 1.04 (1.01 to 1.07) | 1.09 (1.02 to 1.16) |
| Flare after‡ | ||
| Stop attempt first GC course after bridging had ended | 0.99 (0.93 to 1.05) | 0.90 (0.73 to 1.12) |
| DMARD added after flare on stopping GC bridging (%) | 0.94 (0.88 to 1.01) | 0.89 (0.78 to 1.02) |
Associations were evaluated with mixed effects regression analysis with study arm as random effect. For continuous outcomes, we used mixed effects linear regression models (linear mixed models); for dichotomous outcomes, we used mixed effects logistic regression models. This sensitivity analysis was conducted in a dataset without arm 1 of the tREACH study (intramuscular GC bridging) and without the IDEA study (intravenous GC bridging). Due to limited variation in the included groups and thereby collinearity, not all analyses provided results and those without results were therefore ‘omitted’.
All results reported as OR (95% CI) except mean cumulative GC dose which is reported as coefficient (95% CI). Bold text is expressing a significant result after correction for multiple testing.
*Months after the induction schedule and oral GC use.
†Outside induction schedule and oral GC use.
‡Flare defined as: DAS28 increase >1.2 or ∆DAS28 >0.6 if DAS28 at previous visit was ≥3.2.
DAS28, Disease Activity Score based on 28 Joints; DMARD, disease-modifying antirheumatic drug; GC, glucocorticoids.