Five trials published between 1953 and 1975 involving 265 patients were included in a Cochrane review . The trials were small and generally of poor quality. All trials showed positive effects on one of their main outcomes. No serious adverse effects were reported. The relative risk for the combined result of two trials using a random effects model was 0.57 (subjective evaluation of treament) with a 95% CI of 0.28 to 1.15.
Comment: The quality of evidence is downgraded by study quality (unclear allocation concealment), by inconsistency (heterogeneity in interventions and outcomes), and by imprecise results (limited study size for each comparison).