Table II.
Demographic data by country
| Country | USA | UK | Switzerland | Germany | Australia |
|---|---|---|---|---|---|
| Number of studies | 72 | 11 | 7 | 7 | 5 |
| Number of subjects (hips) | 5637 (5830) | 2396 (2412) | 307 (318) | 115 (118) | 671 (678) |
| Level of evidence | 3.76 ± 0.64 | 4 | 3.86 ± 0.38 | 4 | 3.8 ± 0.45 |
| I | 2 | 0 | 0 | 0 | 0 |
| II | 2 | 0 | 0 | 0 | 0 |
| III | 7 | 0 | 1 | 0 | 1 |
| IV | 61 | 11 | 6 | 0 | 4 |
| MCMS | 32.7 ± 11.0 | 39.7 ± 7.6 | 32.7 ± 13.0 | 24.3 ± 13.2 | 30 ± 11.8 |
| Financial conflict of interest | |||||
| Present | 23 | 3 | 1 | 0 | 1 |
| Not present | 36 | 7 | 3 | 3 | 0 |
| Not reported | 13 | 1 | 3 | 4 | 4 |
| Institutional Collaboration | |||||
| Single center | 65 | 11 | 7 | 7 | 5 |
| Multi-center | 7 | 0 | 0 | 0 | 0 |
| Number of subjects | |||||
| Malea | 2552 | 1065 | 57 | 36 | 341 |
| Female | 2561 | 1336 | 109 | 44 | 330 |
| Mean age (years) | 34.2 ± 10.8 | 36.7 ± 11.1 | 34.5 ± 11.4 | 36.2 ± 19.0 | 40.5 ± 17.9 |
| Minimum age (mean across studies) | 23.0 ± 12.6 | 21.7 ± 15.1 | 17.3 ± 4.0 | 23.2 ± 16.0 | 21.3 ± 17.8 |
| Maximum age (mean across studies) | 45.3 ± 18.4 | 64.6 ± 11.1 | 50.2 ± 19.7 | 42 ± 18.1 | 50.3 ± 34.7 |
| Mean BMI (kg/m2) | 26.9 | 28.2 | 24.5 | Nr | Nr |
| Mean length of follow-up (months) | 27.8 ± 25.3 | 28.0 ± 20.4 | 16.3 ± 13.4 | 20.6 ± 11.0 | 21.0 ± 21.6 |
Nr, not recorded.
awhen gender was specified in articles.