Table I.
Baseline characteristics of the patients
| Predictors | All patients | Patients lost to follow-up |
|---|---|---|
| Median age, yrs (IQR); n | 69.0 (63.3 to 74.6); 721 | 69.1 (34.8 to 73.8); 17 |
| Female sex, n (%) | 379 (52.6) | 15/17 (88.2) |
| Education, n (%) | 719 | 17 |
| Secondary school | 356 (49.5) | 11 (64.7) |
| Apprenticeship | 81 (11.3) | 1 (5.9) |
| Further education college | 188 (26.2) | 5 (29.4) |
| University degree | 69 (9.6) | 0 (0) |
| Further degree | 25 (3.5) | 0 (0) |
| Marital status, n (%) | 719 | 17 |
| Single | 35 (4.9) | 0 (0) |
| Married | 485 (67.5) | 11 (64.7) |
| Widowed | 100 (13.9) | 1 (5.9) |
| Divorced | 67 (9.3) | 4 (23.5) |
| Separated | 8 (1.1) | 0 (0) |
| Cohabiting | 24 (3.4) | 1 (5.9) |
| Clinical factors | ||
| Median duration of knee pain, yrs, (IQR); n | 5.0 (2.0 to 10.0); 699 | 5.5 (2.5 to 11.5); 16 |
| Median baseline Oxford Knee Score, score (IQR); n | 21.0 (15.0 to 26.0), 709 | 24.0 (16.0 to 28.0); 14 |
| Median EQ-5D score, (IQR); n | 0.42 (0.25 to 0.42); 699 | 0.42 (0.25 to 0.46); 14 |
| Median EQ-5D VAS score, (IQR); n | 75.0 (62.0 to 85.0); 691 | 70.0 (65.0 to 86.0); 14 |
| Median PROMIS Global Physical Health, score (IQR); n | 37.4 (34.9 to 39.8); 706 | 37.4 (34.9 to 39.8); 15 |
| Median PROMIS Global Mental Health, score (IQR); n | 45.8 (41.4 to 48.3); 712 | 43.5 (41.1 to 49.6); 16 |
| Comorbidities, n (%) | 721 | |
| ⩽ 1 | 175 (24.3) | 10 (58.8) |
| 2 to 3 | 421 (58.4) | 6 (35.3) |
| ≥ 4 | 125 (17.3) | 1 (5.9) |
IQR, interquartile range; EQ-5D, EuroQol five-dimensions; VAS, visual analogue scale; PROMIS, Patient-Reported Outcomes Measurement Information System