Table 2.
| Table 2a. Predictors of VAS pain scores during the crossover trial* | ||
|---|---|---|
| Predictor | Model 1 | Model 2 |
| Baseline VAS pain score (95% confidence interval) | 0.55 (0.41, 0.68) | 0.56 (0.43, 0.69) |
| p-value | <0.0001 | <0.0001 |
| Treatment (95% confidence interval) | 3.71 (−7.23, 14.65) | −0.68 (−6.20,4.84) |
| p-value | 0.5010 | 0.8055 |
| Treatment, period 1 vs. period 2 (95% confidence interval) | 0.89 (−9.33,11.11) | −3.06 (−8.82, 2.71) |
| p-value | 0.8627 | 0.2934 |
| Period by treatment interaction † (95% confidence interval) | 7.70 (−8.89, 24.29) | |
| p-value | 0.3573 | |
| Table 2b. Predictors of WOMAC pain scores during the crossover trial* | ||
|---|---|---|
| Predictor | Model 1 | Model 2 |
| Baseline WOMAC pain score (95% confidence interval) | 0.56 (0.43, 0.69) | 0.58 (0.45, 0.71) |
| p-value | <0.0001 | <0.0001 |
| Treatment (95% confidence interval) | 1.33 (−0.22, 2.88) | 0.11 (−0.66, 0.88) |
| p-value | 0.0912 | 0.7744 |
| Treatment, period 1 vs. period 2 (95% confidence interval) | 1.24 (−0.19, 2.67) | 0.16 (−0.62, 0.94) |
| p-value | 0.0877 | 0.6883 |
| Period by treatment interaction † (95% confidence interval) | 2.17 (−0.24, 4.57) | |
| p-value | 0.0769 | |
| Table 2c. Predictors of WOMAC function scores during the crossover trial* | ||
|---|---|---|
| Predictor | Model 1 | Model 2 |
| Baseline WOMAC function score (95% confidence interval) | 0.80 (0.69, 0.92) | 0.81 (0.70, 0.92) |
| p-value | <0.0001 | <0.0001 |
| Treatment (95% confidence interval) | 0.70 (−4.62, 6.01) | −0.02 (−2.83,2.79) |
| p-value | 0.7943 | 0.9878 |
| Treatment, period 1 vs. period 2 (95% confidence interval) | −1.01 (−5.59, 3.57) | −1.57 (−4.59, 1.46) |
| p-value | 0.6620 | 0.3056 |
| Period by treatment interaction † (95% confidence interval) | 1.10 (−5.74, 7.93) | |
| p-value | 0.7499 | |
| Table 2d. Predictors of WOMAC stiffness scores during the crossover trial* | ||
|---|---|---|
| Predictor | Model 1 | Model 2 |
| Baseline WOMAC stiffness score (95% confidence interval) | 0.65 (0.52, 0.78) | 0.67 (0.54, 0.80) |
| p-value | <0.0001 | <0.0001 |
| Treatment (95% confidence interval) | 0.23 (−0.49, 0.95) | −0.11 (−0.53, 0.32) |
| p-value | 0.5293 | 0.6129 |
| Treatment, period 1 vs. period 2 (95% confidence interval) | 0.26 (−0.39, 0.91) | −0.02 (−0.46, 0.42) |
| p-value | 0.4256 | 0.9314 |
| Period by treatment interaction † (95% confidence interval) | 0.55 (−0.41, 1.51) | |
| p-value | 0.2548 | |
*
Values for model predictors are beta coefficients. For treatment as a predictor, a value of x means that active treatment was associated with a x lower score on the VAS pain scale compared with control treatment. An unstructured correlation matrix for observations within participants was used in generalized estimating equation fitting of the marginal model (1). Model 2 was conducted with exclusion of the differential carryover effect.
†
Tests whether treatment effects differed according to use in period 1 or period 2, constituting the differential carryover effect.