Table 2.
Nested Regression Analyses Using OAI and MOST Datasets With Index WOMAC Pain as the Dependent Variablea
| OAI | MOST | |||||||
|---|---|---|---|---|---|---|---|---|
| Variable | Estimate | 95% CI (SE) | t | P | Estimate | 95% CI (SE) | t | P |
| Model 1 | R 2 = 0.48 | R 2 = 0.64 | ||||||
| Intercept | −0.56 | −0.76 to −0.37 (0.10) | −5.72 | <.0001 | 1.51 | 1.33 to 1.68 (0.09) | 16.64 | <.0001 |
| Generic knee pain | 1.06 | 1.02 to 1.10 (0.02) | 53.18 | <.0001 | 0.13 | 0.12 to 0.13 (0.00) | 56.96 | <.0001 |
| Model 2 | R 2 = 0.52 | Δ R2 = 0.03 | F = 41.6 | < .0001 | R 2 = 0.66 | Δ R2 = 0.02 | F = 18.2 | < .0001 |
| Intercept | −0.61 | −0.83 to −0.39 (0.11) | −5.46 | <.0001 | 1.10 | 0.86 to 1.35 (0.12) | 8.9 | <.0001 |
| Generic knee pain | 0.94 | 0.89 to 0.99 (0.02) | 39.98 | <.0001 | 0.13 | 0.12 to 0.13 (0.003) | 41.2 | <.0001 |
| Lower extremity pain | 0.38 | −0.30 to .0.45 (0.04) | 9.65 | <.0001 | 0.20 | 0.13 to 0.26 (0.03) | 5.8 | <.0001 |
| Contralateral generic knee pain | 0.08 | 0.03 to 0.13 (0.03) | 3.19 | .0014 | −0.01 | −0.02 to 0.0 (0.004) | −2.5 | .0117 |
| Back pain | F(3, 3004) = 18.3 | <.0001 | F(3, 1831) = 11.0 | <.0001 | ||||
| None (reference) | - | - | - | - | - | - | - | - |
| Mild | −0.09 | −0.31 to 0.13 (0.11) | −0.78 | .4362 | 0.04 | −0.24 to 0.32 (0.14) | 0.29 | .7728 |
| Moderate | 0.14 | −0.10 to 0.37 (0.12) | 1.13 | .2568 | 0.46 | 0.20 to 0.73 (0.13) | 3.45 | .0006 |
| Severe | 1.43 | 1.02 to 1.83 (0.21) | 6.88 | <.0001 | 1.18 | 0.71 to 1.65 (0.24) | 4.96 | <.0001 |
| Model 3 | R 2 = 0.53 | Δ R2 = 0.01 | F = 9.9 | < .0001 | R 2 = 0.66 | Δ R2 = 0.003 | F = 3.8 | .0019 |
| Intercept | −0.28 | −0.61 to 0.06 (0.17) | −1.6 | .1056 | 1.07 | 0.71 to 1.43 (0.18) | 5.89 | <.0001 |
| Generic knee pain | 0.88 | 0.80 to 0.95 (0.04) | 22.9 | <.0001 | 0.13 | 0.12 to 0.14 (0.00) | 25220 | <.0001 |
| Lower extremity pain | 0.17 | 0.0 to 0.33 (0.08) | 2.0 | .0462 | 0.15 | 0.03 to 0.27 (0.06) | 2.39 | .0169 |
| Contralateral knee pain | −0.15 | −0.27 to −0.02 (0.07) | −2.2 | .0254 | 0.02 | 0.00 to 0.03 (0.01) | 2.11 | .0347 |
| Back pain | F(3, 2999) = 18.6 | <.0001 | F(3, 1826) = 11.1 | <.0001 | ||||
| None (reference) | - | - | - | - | - | - | - | - |
| Mild | 0.31 | −0.14 to 0.75 (0.22) | 1.4 | .1724 | −0.21 | −0.67 to 0.26 (0.24) | −0.87 | 0.3821 |
| Moderate | 0.27 | −0.24 to 0.78 (0.26) | 1.0 | .2996 | 0.35 | −0.11 to 0.81 (0.23) | 1.50 | 0.1338 |
| Severe | −0.05 | −1.08 to 0.98 (0.52) | −0.1 | .9239 | 0.38 | −0.51 to 1.28 (0.46) | 0.84 | 0.3999 |
| Generic knee pain x lower extremity pain | 0.04 | 0.01 to 0.07 (0.01) | 2.5 | .0111 | 0.00 | 0.00 to 0.00 (0.00) | 0.79 | 0.4325 |
| Generic knee pain x contralateral knee pain | 0.03 | 0.01 to 0.05 (0.01) | 3.4 | .0006 | 0.00 | 0.00 to 0.00 (0.00) | −3.80 | 0.0001 |
| Generic knee pain x back pain | F(3, 2999) = 4.6 | .0031 | F(3, 1826) = 2.0 | 0.11 | ||||
| None (reference) | - | - | - | - | - | - | - | - |
| Mild | −0.05 | −0.19 to 0.01 (0.05) | −1.8 | .0668 | 0.01 | 0.00 to 0.02 (0.01) | 1.30 | 0.1937 |
| Moderate | −0.02 | −0.12 to 0.08 (0.05) | −0.4 | .6963 | 0.00 | −0.01 to 0.01 (0.01) | 0.56 | 0.5723 |
| Severe | 0.21 | 0.05 to 0.38 (0.08) | 2.6 | .0103 | 0.02 | 0.00 to 0.04 (0.01) | 2.24 | 0.0254 |
a
MOST = Multicenter Osteoarthritis Study; OAI = Osteoarthritis Initiative; SE = standard error; WOMAC = Western Ontario and McMaster Universities Osteoarthritis.