Xuxi Zhang

significant. For HbA 1c measured >6 months after the end of intervention 13, 30 , we found no heterogeneity ( I 2 = 0%) but there was opposite result that the difference in HbA 1c outcomes between IG and CG was 0.01% (95% CI  ‐ 0.32 to 0.34), or 0.1mmol/mol without statistical significance ( P = 0.939). The differences among these four groups were not significant ( P = 0.115). DISCUSSION AND CONCLUSIONS Discussion Peer support interventions have significantly positive effect on glycemic control for patients with T2DM with pooled effect on HbA1c of  ‐ 0.16% (95% CI  ‐ 0.25 to  ‐ 0.07) or  ‐ 1.7mmol/mol ( P < 0.001) and acceptable heterogeneity among studies ( I 2 = 49.5%). As mentioned in the Introduction, a 1% reduction in HbA1c has been associated with “reductions in risk of 21% for any end point related to diabetes, 21% for deaths related to diabetes, 14% for myocardial infarction, and 37% for microvascular complications”. 6 Therefore, the effect of peer support on glycemic control is important for the treatment of patients. The differences of peer support providers may influence the effect of peer support. There is significant difference in outcomes ( P = 0.009) among the three categories of providers. Peer ‐ partner ‐ intervention demonstrates significantly positive effect with the best HbA 1c outcome of  ‐ 0.49% (95% CI  ‐ 0.86 to  ‐ 0.12) or  ‐ 5.4mmol/mol ( P = 0.009). Community ‐ health ‐ worker ‐ intervention also achieves an impressive pooled effect of  ‐ 0.35% (95% CI  ‐ 0.54 to  ‐ 0.16) or  ‐ 3.8 mmol/mol ( P < 0.001). For Peer ‐ leader ‐ intervention, however, the difference between control and intervention conditions was not significant ( P = 0.141). There may be a number of reasons for these differences by type of peer provider. In Peer ‐ partner ‐ intervention, participants may have better self ‐ regulation ability because each patient has to be able to implement as well as receive the intervention. Those receiving Community ‐ health ‐ worker ‐ intervention may be managed or educated better than those receiving Peer ‐ leader ‐ intervention because nonprofessionals providing Community ‐ health ‐ worker ‐ intervention are more skilled and responsible than specific patient leaders. However, it is important to note that these differences by provider were based on small numbers of studies (e.g., only 2 in Peer ‐ partner ‐ intervention category). Also, because of the small numbers of studies, other characteristics (e.g., age, sex, baseline characteristics) were not controlled in statistical analyses. Therefore, the differences by provider should be taken as tentative, a basis for further research, not a firm basis for programmatic decisions. Turning to the types of peer support, differences among categories were not significant. Curriculum ‐ combined ‐ reinforcement ‐ intervention and Home ‐ visit ‐ intervention achieve significant positive effects on glycemic control relative to control conditions. Although not significant, the observed positive benefit of Telephone ‐ dominant ‐ intervention is consistent with a previous systematic review and meta ‐ analysis which found effects of phone ‐ call ‐ intervention on glycemic control in 5 trails with 953 diabetes patients. 35 144 Chapter 6