Adjusted incidence rate ratios (IRR) of developing a serious infection in the first or second year
| Model A | Model B | Fully adjusted model C | |||||
|---|---|---|---|---|---|---|---|
| IRR | 95% CI | IRR | 95% CI | IRR | 95% CI | p Value | |
| Age >60 years (yes vs no) | 1.7 | 1.3 to 2.3 | 1.7 | 1.3 to 2.3 | 1.6 | 1.1 to 2.4 | 0.012 |
| Chronic lung disease (yes vs no) | 2.6 | 1.8 to 3.7 | 2.3 | 1.6 to 3.3 | 1.7 | 1.1 to 2.6 | 0.014 |
| Chronic renal disease (yes vs no) | 2.3 | 1.5 to 3.7 | 2.1 | 1.3 to 3.3 | 1.6 | 0.9 to 2.8 | 0.14 |
| High number of treatment failures (>5) at baseline (yes vs no) | 1.2 | 0.8 to 1.7 | 1.1 | 0.8 to 1.6 | 1.6 | 1.1 to 2.3 | 0.027 |
| History of serious infection at follow-up (yes vs no) | – | – | 2.1 | 1.0 to 4.3 | 0.038 | ||
| FFbH (0–100%) per 10% at baseline | 0.92 | 0.87 to 0.98 | |||||
| FFbH (0–100%) per 10% at follow-up | 0.90 | 0.86 to 0.95 | 0.90 | 0.85 to 0.96 | 0.0023 | ||
| Glucocorticoids 7.5–14 mg/day at baseline (yes vs no) | 1.0 | 0.7 to 1.4 | |||||
| Glucocorticoids 7.5–14 mg/day at follow-up (yes vs no) | 1.9 | 1.4 to 2.6 | 2.1 | 1.4 to 3.2 | 0.0002 | ||
| Glucocorticoids ≥ 15 mg/day at baseline (yes vs no) | 1.5 | 1.0 to 2.1 | |||||
| Glucocorticoids ≥ 15 mg/day at follow-up (yes vs no) | 3.6 | 2.2 to 5.7 | 4.7 | 2.4 to 9.4 | <0.0001 | ||
| Treatment with TNF inhibitors (yes vs no) | 1.6 | 1.2 to 2.3 | 1.6 | 1.2 to 2.3 | 1.8 | 1.2 to 2.7 | 0.0027 |
| Trend (IRR TNF year 2/IRR TNF year1) | 0.69 | 0.50 to 0.96 | 0.79 | 0.57 to 1.10 | (1.0) | (0.5 to 2.0) | (0.93) |
Model A: only baseline characteristics were used for calculation and adjustment.
Model B: time-dependent use of glucocorticoids and FFbH were considered in the model. No adjustment for DMARD/anti-TNF treatment adaptations and dropout processes at follow-up.
Model C: fully adjusted model. Adjustment for time-varying risk factors as in model B and for treatment adaptations and dropout processes (see Methods section for further details).
DMARD, disease-modifying antirheumatic drug; FFbH, Hannover Functional Status Questionnaire measuring functional capacity as percentage of full function; TNF, tumour necrosis factor.