| Study | Reason for exclusion |
|---|---|
| Muller‐Wiefel 1989 | Published only in abstract form, not enough data available for the outcomes of interest; Unsuccessful attempt to obtain more data. RCT, method of randomisation not specified. |
| Thomson 1987 | Published only in abstract form, not enough data available for the outcomes of interest; Unsuccessful attempt to obtain more data. RCT, method of randomisation not specified. |
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