Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.
| Methods | See van Schayck 1991a | |
| Participants | ||
| Interventions | ||
| Outcomes | ||
| Notes | This comparison not analysed, so details not extracted. | |
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Allocation concealment (selection bias) | Unclear risk | Information not available (Cochrane Grade B) |
