The authors stated that eight RCTs, nine non-randomised comparative studies and 26 descriptive studies were included (number of participants not reported).
The average quality score for RCTs was 18.7 out of 30 (range 15 to 20) for programme description and 11.6 out of 13 (range 10 to 13) for research quality. In six RCTs, the size of treatment groups was between 15 and 36.
One-on-one face to face: One RCT reported increased self-efficacy from baseline to eight weeks in the intervention group, but no difference between intervention and control in depression scores at eight weeks.
One-on-one telephone (two RCTs): One RCT reported more support providers in the intervention group. The other RCT reported significantly higher rates of changes in relationships in the intervention group but no significant difference between treatment groups in emotional distress.
Group face-to-face (three RCTs): Studies reported no significant difference between treatment groups in health-related quality of life (one study), psychosocial adjustment (one study) and depression, anxiety, interpersonal problems, anger and life satisfaction (one study). One study reported an increased perception of greater social support in the intervention group.
Group Internet (two RCTs): Both RCTs reported improved psychosocial functioning in intervention compared to control groups. Significant improvements were reported for depression, perceived post-traumatic stress (one study) and perceived support, and increased confidence in health; no significant difference was found between groups in quality of life (one study).
The average quality score for non-randomised comparative studies was 12.7 out of 30 for programme description and 6.7 out of 13 for research quality.
Studies reported improvements in at least one measure of psychosocial functioning for one-on-one face to face programmes (four studies). No treatment group differences or negative findings among intervention groups were reported for group face-to face programmes (one study). Reports of group internet programmes suggested results may have been influenced by patient characteristics (three studies).
The average quality score for one group descriptive data was 15.9 out of 30 for programme description and 5.5 out of 13 for research quality.
Study findings suggested high levels of patient satisfaction with peer-support programmes and some improvements in psychosocial functioning.