Table 2.
Univariable associations between individual preoperative variables and poor outcome
| Predictors | Persons with poor outcomea | Total, n | Odds ratio (95% CI) | |
|---|---|---|---|---|
| Sociodemographic factors | ||||
| Age, years | 67.8 (9.0) | 704 | 0.99 (0.96, 1.01) | |
| Sex | ||||
| Female | 55 (15.1) | 704 | Reference category | |
| Male | 44 (12.9) | 0.84 (0.54, 1.28) | ||
| Clinical factors | ||||
| Duration of knee pain, years | 8.4 (7.6) | 682 | 1.02 (0.998, 1.05*) | |
| Baseline Oxford knee score; per unit (0–48) | 15.2 (6.8) | 695 | 0.87 (0.84, 0.91*) | |
| Chronic pain grade | ||||
| No pain, grade 0 | 4 (3.3) | 651 | Reference category | |
| Low disability and low intensity, grade I | 2 (3.8) | 1.16 (0.21, 6.53) | ||
| Low disability and high intensity, grade II | 12 (7.1) | 2.25 (0.71, 7.17) | ||
| High disability and moderate intensity, grade III | 24 (16.7) | 5.90 (1.98, 17.54*) | ||
| High disability and high intensity, grade IV | 45 (27.6) | 11.25 (3.92, 32.30*) | ||
| Chronic widespread pain | ||||
| No | 78 (12.5) | 697 | Reference category | |
| Yes | 18 (25.0) | 2.34 (1.30, 4.19*) | ||
| Sleep problem scale | ||||
| Mildly sleep disturbed (≤15 nights) | 77 (13.0) | 699 | Reference category | |
| Severely sleep disturbed (>15 nights) | 21 (19.8) | 1.66 (0.97, 2.83*) | ||
| Co-morbidities | ||||
| ≤1 co-morbidities | 14 (8.5) | 704 | Reference category | |
| 2–3 co-morbidities | 53 (12.8) | 1.58 (0.85, 2.93) | ||
| ≥4 co-morbidities | 32 (25.8) | 3.75 (1.90, 7.40*) | ||
| Psychosocial factors | ||||
| Illness attitude score; per unit (0–108) | 31.9 (13.4) | 655 | 1.03 (1.01, 1.05*) | |
| Active coping; per unit (7–35) | 21.1 (4.6) | 562 | 0.87 (0.83, 0.92*) | |
| Passive coping; per unit (11–55) | 33.6 (7.6) | 547 | 1.08 (1.05, 1.12*) | |
| Expectations of pain after recovery; per unit (0–100) | 51.4 (29.0) | 685 | 1.01 (1.01, 1.02*) | |
| Expectations of limitations after recovery; per unit (0–100) | 43.5 (25.4) | 685 | 1.02 (1.01, 1.02*) | |
| Mental and physical health | ||||
| HADSb anxiety | ||||
| Mild to moderate anxiety | 84 (12.8) | 702 | Reference category | |
| Severe anxiety | 15 (34.9) | 2.58 (1.48, 4.49*) | ||
| HADS depression | ||||
| Mild to moderate depression | 78 (12.5) | 702 | Reference category | |
| Severe depression | 21 (26.9) | 3.67 (1.88, 7.15*) | ||
| PROMISc mental health; per unit (4–20) | 42.6 (5.6) | 696 | 0.93 (0.89, 0.97*) | |
| PROMISc physical health; per unit (4–20) | 35.0 (3.6) | 691 | 0.82 (0.77, 0.87*) | |
| Quality of life | ||||
| EQ-5D; per 10th of a unit (−0.5, 1.0) | 2.6 (1.8) | 685 | 0.74 (0.65, 0.83*) | |
aFor categorical variables, the number and percentages of persons with poor outcome are reported. Means (s.d.) of persons with poor outcome are reported for continuous variables.
bHospital anxiety and depression scale.
cPatient-reported outcomes measurement information system.
*
P < 0.2.