Participant and follow-up characteristics
| Non-operative control | Placebo control | P value | |
| N | 38 | 61 | |
| Age of study cohorts (mean±SD, n) | |||
| Surgical intervention group | 54.8±12.6, n=34 | 50.4±13.4, n=55 | 0.125 |
| Control group | 55.1±13.0, n=34 | 50.5±13.3, n=55 | 0.114 |
| Other group* | 48±8, n=3 | 47.8±5.8, n=4 | 0.807 |
| Gender of study cohorts (mean+SD) | |||
| Per cent female | 62.7±24.8 | 61.8±30.9 | 0.87 |
| Follow-up characteristics (median (IQR)) | |||
| Number of timepoints† | 3 (2–5) | 4 (2–6) | 0.412 |
| Timepoint (primary outcome), days | 365 (183–730) | 274 (91–365) | 0.006 |
| Timepoint (longest), days | 365 (365–730) | 365 (183–730) | 0.193 |
*Other group only applicable to trials incorporating three treatment arms.
†Number of follow-up points was not available for five studies (one non-operative control and four placebo).
N, number of studies.