Xuxi Zhang

16, Ruggiero, L., 2010 [25] Baseline: In total: 50; IG: 25; CG: 25 Follow ‐ up intervals (0 month): CR: 84%; IG: 24 Attrition: 4%; CG: 18 Attrition: 28% (There were no significant difference between IG and CG before and after the intervention.) Patients: Diagnosis of type 2 diabetes for at least one year, last two HbA1c ≥ 7%, prescribed diabetes medication Mean age: 65.8 Female (%): 66% Insulin usage (%):  ‐‐  Other features: Latino or African American RCT United States CHWI/CCRI 6 months 17, Long, J. A., 2012 [21] Baseline (with HbA 1c data) †† :In total: 77; IG: 38; CG: 39 Follow ‐ up intervals (0 month, with HbA 1c data): CR: 98.7%; IG: 37 Attrition: 5.1%; CG: 39 Attrition: 0% Patients: Aged 50 to 70 years with persistently poor diabetes control Mean age: 60 Female (%): 5% Insulin usage (%):  ‐‐  Other features: Self ‐ identified race of black or African American RCT United States PLI/TDI 6 months 18, Tang, T. S., 2014 [13] Baseline: In total: 116; IG: 60; CG: 56 Follow ‐ up intervals (0 month, with HbA 1c data): CR: 82.8%; IG: 49 Attrition: 18.3%; CG: 47 Attrition: 16.1% Follow ‐ up intervals (6 month, with HbA 1c data): CR: 71.6%; IG: 42 Attrition: 39%; CG: 41 Attrition: 26.8% Follow ‐ up intervals (12 month, with HbA 1c data): CR: 59.5%; IG: 37 Attrition: 38.3%; CG: 32 Attrition: 42.9% (Loss to follow ‐ up was not different between the two groups and was not associated with clinical or demographic variables) Patients: Receiving medical care at CHASS with physician ‐ diagnosed type 2 diabetes Mean age: 49.3 Female (%): 52% Insulin usage (%):Baseline 26% Other features: Self ‐ identified as Latino RCT United States PLI/CCRI 6 months 19, Chan, J. C. N., 2014 [17] Baseline: In total: 628; IG: 312; CG :316 Follow ‐ up intervals (0 month):CR: 93.3%; IG: 296 Attrition: 5.1%; CG: 290 Attrition: 8.2% Patients: Had type 2 diabetes, underwent comprehensive assessments and expressed willingness to participate Mean age: 54.7 Female (%): 43.5% Insulin usage (%):Baseline 28.8% Other features:  ‐‐  RCT China HK PLI/TDI 12 months 20, Heisler, M., 2010 [26] Baseline: In total: 244; IG: 125; CG :119 Follow ‐ up intervals (0 month, with HbA 1c data): CR: 88.5%; IG: 113 Attrition: 9.6%; CG: 103 Attrition: 13.4% Patients: Diabetes patients with HbA1c in the prior 6 months of 7.5% or more Mean age: IG:61.8 CG:62.3 Female (%): 0% Insulin usage (%):  ‐‐  Other features: ‐‐  RCT United States PPI/CCRI 6 months * If there is no special explanation, there are no significant differences in the demographic characteristics and dependent variables between IG and CG. Mostly, the content of characteristics is the description of all the participants in both IG and CG. If they were described separately, there would be labels of IG and CG. 6 137 Peer support among adults with type 2 diabetes