Table 1. Studies meeting inclusion criteria.
| Trial | N random’d PHB | N random’d PHT | 1st sz/rem PHB | 1st sz/rem PHT | Withdrawal PHB | Withdrawal PHT | Follow-up median | Mean age (range) | % male |
| IPD available | |||||||||
| Mattson 1985 | 155 | 165 | 151 | 162 | 155 | 165 | 20 months (range 0-66) | 40 (18-81) | 88 |
| Heller 1995 | 58 | 63 | 58 | 63 | 55 | 61 | 61 months (1-156) | 34 (14-77) | 49 |
| de Silva 1996 | 10 | 54 | 10 | 54 | 10 | 53 | 103 months (30-164) | 9 (3-16) | 59 |
| Pal 1998 | 47 | 47 | 47/30 | 47/27 | - | - | 9 months (0-12) | 11 (2-18) | 52 |
| No IPD: | |||||||||
| Czapinski 1997 | 30 | 30 | Not reported | Not reported | Not reported | Not reported | Not reported | Not reported (18-40) | Not reported |
| Thilothammal 1996 | 51 | 52 | Not reported | Not reported | Not reported | Not reported | Not reported (22-36) | Not reported (4-12) | 54 |
| Meador 1990 | 15 | 15 | Not reported | Not reported | Not reported | Not reported | Not reported | Not reported (19-62) | 60 |
| Cereghino 1974 | 45 | 45 | Not reported | Not reported | Not reported | Not reported | Not reported | Not reported (18-51) | 62 |
| Bird 1966 | Not reported | Not reported | Not reported | Not reported | Not reported | Not reported | Not reported | Not reported | 43 |
| Gruber 1962 | 48 | 48 | Not reported | Not reported | Not reported | Not reported | Not reported | Not reported | Not reported |