Characteristics of the 206 patients included in the IPD meta-analysis
| Variable | Value |
| Sex, no. (%) | |
| Male | 106 (51.5) |
| Female | 61 (29.6) |
| Missing | 39 (18.9) |
| Age, years | |
| Mean (SD) | 61.0 (8.3) |
| Disease duration, years | |
| Mean (SD) | 10.6 (5.2) |
| Unilateral/bilateral, no. (%) | |
| Unilateral | 6 (3) |
| Bilateral | 200 (97) |
IPD, individual patient data.