Table 2.
Repeated measures analysis of covariance models to identify predictors of the average Oxford Hip Score (OHS) between 1-year and 5-year follow-up
| Variable | Univariable Δ coefficient (95% CI) |
p Value | Multivariable Δ coefficient (95% CI) |
p Value |
|---|---|---|---|---|
| Patient variables | ||||
| Baseline total Oxford Hip Score (10 units) | 3.68 (3.16 to 4.20) | <0.001 | 2.68 (2.16 to 3.21) | <0.001 |
| Year | 0.02 (−0.10 to 0.13) | 0.77 | 0.01 (−0.11 to 0.13) | 0.88 |
| Age | ||||
| <50 | −1.44 (−3.92 to 1.03) | 0.25 | ||
| 50–60 | −0.96 (−2.27 to 0.35) | 0.15 | −1.87 (−3.22 to −0.53) | 0.006 |
| 60–70 | 0.00 (0.00 to 0.00) | – | 0.00 (0.00 to 0.00) | – |
| 70–80 | −0.37 (−1.20 to 0.46) | 0.38 | −1.49 (−2.37 to −0.61) | 0.001 |
| 80+ | −2.29 (−3.69 to −0.88) | 0.001 | −3.81 (−5.29 to −2.33) | <0.001 |
| BMI (10 units) | −1.14 (−2.05 to −0.22) | 0.02 | −1.54 (−2.45 to −0.64) | 0.001 |
| Number of coexisting diseases | −1.06 (−1.43 to −0.69) | <0.001 | −0.90 (−1.27 to −0.54) | <0.001 |
| SF-36 mental health score (10 units) | 0.80 (0.50 to 1.11) | <0.001 | 0.76 (0.46 to 1.07) | <0.001 |
| Surgical variables | ||||
| Femoral component offset size (mm offset) | 0.15 (0.04 to 0.26) | 0.01 | 0.17 (0.06 to 0.28) | 0.002 |
| R2 | 17.4% | |||
| Optimism | 0.8% | |||
| Bias-corrected R2 | 16.6% | |||
Δ: represents the average follow-up OHS between 1, 2, 3, 4 and 5 years follow-up.
Variables included in the final regression model are those that are retained in at least 70% of the 200 bootstrap backward selection regression models.
Univariable—each predictor in the model is adjusted for baseline OHS only.