Probability of membership to one of three identified clusters
| Cluster 1 | Cluster 2 | Cluster 3 | Total (%) | |
| Probability of r efusing p articipation | 22% | 38% | 62% | 36 |
| N | 176 | 382 | 84 | |
| Characteristic | ||||
| Age | ||||
| >80 | 1% | 16% | 12% | 6 |
| 66–80 | 5% | 5% | 37% | 15 |
| 41–65 | 46% | 42% | 28% | 40 |
| <40 | 48% | 36% | 24% | 39 |
| Socioeconomic status (quintile) | ||||
| 1 (highest) | 32% | 2% | 42% | 32 |
| 2 | 31% | 6% | 43% | 32 |
| 3 | 13% | 49% | 6% | 15 |
| 4 | 11% | 25% | 5% | 11 |
| 5 (lowest) | 14% | 17% | 4% | 11 |
| Alcohol use | 71% | 3% | 36% | 52 |
| Multifracture | 20% | 8% | 0% | 13 |
| Multiple surgeries | 47% | 35% | 28% | 40 |