Table 3.
Multiple linear regression analyses of demographic, clinical, symptom, and psychological factors on pre- and postoperative self-rated health in patients undergoing total knee arthroplasty (TKA)
| Independent variables | Beta | B | 95% CI | Explained variance (R 2) | Change of variance (R 2 –change) | P-value |
|---|---|---|---|---|---|---|
| Self-rated health prior to surgery | ||||||
| Step 1. Demographic characteristics | 8.5% | 8.5% | .001 | |||
| Age | .06 | .12 | −.18 to .42 | |||
| Sex (male as reference) | −.08 | −3.39 | −9.16 to 2.39 | |||
| Step 2. Clinical characteristics | 18.2% | 9.7% | <.001 | |||
| Number of comorbidities | −.05 | −1.02 | −3.69 to 1.66 | |||
| C-reactive protein | −.25 | −1.63 | −2.51 to−.74 | |||
| Step 3. Pain characteristics | 25% | 6.8% | <.001 | |||
| Number of painful sites before surgery | −.18 | −2.17 | −3.88 to−.46 | |||
| Step 4 Preoperative symptoms | 32.7% | 7.7% | <.001 | |||
| Fatigue severity (higher = more fatigue) | −.22 | −1.99 | −3.45 to−.54 | |||
| Step5 Psychological characteristics | 37.0% | 4.3% | .002 | |||
| Illness concern (higher = more concern) | −.24 | −1.82 | −2.97 to−.66 | |||
| Self-rated health 12 months after TKA | ||||||
| Step 1. Demographic characteristics | 3.5% | 3.5% | .12 | |||
| Age | −.02 | −.04 | −.27 to .20 | |||
| Sex (male as reference) | .06 | 1.99 | −2.53 to 6.52 | |||
| Step 2. Clinical characteristics | 15.8% | 12.3% | <.001 | |||
| Body mass index | −.15 | −.53 | −.98 to−.07 | |||
| Number of comorbidities | .07 | −1.11 | −3.19 to .96 | |||
| Step 3. Pain characteristics | 42.9% | 27.1% | <.001 | |||
| Number of painful sites 12 months after surgery | −.17 | −2.18 | −3.93 to−.42 | |||
| Pain interference walking group (Continuous improvement group as reference) | −.33 | −12.45 | -.17.67 to -7.24 | |||
| Step 4 Perioperative characteristics | 45.3% | 2.4% | .025 | |||
| Ketamine Yes/No – No as reference | −0.15 | −6.95 | −12.80 to −1.10 | |||
| Step 5 Preoperative symptoms | 51.0% | 5.7% | <.001 | |||
| Depression | −.21 | −1.08 | −1.80 to −.37 | |||
| Step 6 Psychological characteristics | 52.9% | 1.8% | .04 | |||
| Personal control | −.12 | −.84 | −1.74 to .07 | |||
| Step 7 Health characteristics | 56.1% | 3.2% | .005 | |||
| Preoperative self-rated health | .21 | .17 | .05 to .29 | |||
Statistically significant defined as p ≤ 0.05. Bold coefficient = statistically significant
Abbreviations: Beta standardized beta coefficient, B unstandardized coefficient, CI confidence interval, SE standard error