OBJECTIVES: Both depression and diabetes distress can negatively impact self-management behaviors among adult patients living with type 2 diabetes (T2D). The primary objective of this systematic review was to report evidence and gaps in the literature for the impact of peer support interventions on two mental health comorbidities—depression and diabetes distress in adults living with T2D.

METHODS: The inclusion criteria included peer support interventions for depression and/or diabetes distress for adults living with T2D. Randomized controlled trials (RCT) published from January 2000 to December 2021 were assessed on databases including PubMed, MEDLINE, CINAHL, and PsychINFO. Target outcomes included changes in mental health (depression and diabetes distress) and clinical outcomes (Hemoglobin A1c (HbA1c), Body Mass Index (BMI), blood pressure, and cholesterol levels). The formats for peer support or peer-based interventions included in-person, online, and telephone-based.

RESULTS: A total of 28 studies were included in the systematic review. For mental health comorbidities, 11 studies focused on both depression and diabetes distress, 10 studies focused solely on depression, and 7 studies on diabetes distress. Of these studies, 9 studies showed significant improvements in depressive symptoms and 7 studies reported significant improvements in diabetes distress. For clinical outcomes, seven studies reported a significant reduction in HbA1c in the peer support group compared to the control group, three studies for blood pressure, two studies for BMI, and two studies for cholesterol levels. Of the studies that assessed cholesterol levels, one study reported significant reduction in Low Density Lipoprotein (LDL) and High Density Lipoprotein (HDL), and one study reported significant reduction in total cholesterol.

CONCLUSIONS: Peer support or peer-based interventions were most effective in reducing depressive symptoms. The clinical outcomes were most improved for HbA1c and blood pressure.