Table 2.
Parameter values for the final model
| Parameter | Description | Estimate (95% CI) | Shrinkage (%) | |
|---|---|---|---|---|
| Population parameter | ||||
| BASE | θ1 | Baseline DAS28 | 0.472 (0.392, 0.552) | |
| θ4 | Effect of age | 0.672 (0.406, 0.938) | ||
| θ5 | Effect of i.m. corticosteroid administration on BASE | 0.737 (0.379, 1.095) | ||
| EX1 | θ2 | ΔDAS28 | −1.28 (−1.17, −1.39) | |
| θ6 | Effect of systemic corticosteroids on EX1 (during 60 week period) | −0.237 (−0.079, −0.394) | ||
| EX2 | θ3 | Rate constant, week−1 | 0.111 (0.093, 0.129) | |
| θ7 | Effect of currently smoking on EX2 | −0.398 (−0.145, −0.651) | ||
| Population parameter variability | ||||
| BASE (η1) | ω1 | SD | 0.492 (0.348, 0.636) | 13.3 |
| EX1 (η2) | ω2 | SD | 0.740 (0.536, 0.945) | 14.4 |
| EX2 (η3) | ω3 | % CV | 86.1 (42.1, 130) | 30.9 |
| Covariance | ||||
| θ1, θ2 | ω1,2 | Covariance between BASE and EX1 | −0.376 | |
| θ1, θ3 | ω1,3 | Covariance between BASE and EX2 | −0.137 | |
| θ2, θ3 | ω2,3 | Covariance between EX1 and EX2 | 0.651 | |
| Combined residual error | ||||
| Proportional error | σ1 | % CV | 18.4 (0, 37.5) | |
| Additive error | σ2 | DAS28 units (SD) | 0.327 (0.249, 0.405) | |