Comparative efficacy of social support on glycemic control for type 2 diabetes in low- and middle-income countries or among minoritized groups in high-income countries: a systematic review and network meta-analysis

A systematic review and network meta-analysis was implemented to compare social support interventions for glycemic control in people with type 2 diabetes from low- and middle-income countries (LMICs) and those from racial and ethnic minoritized groups in high-income countries (HICs). MEDLINE, EMBASE, and the Cochrane Central Register of Controlled Trials were searched from inception to October 23, 2023. Randomized controlled trials were included, comparing social support intervention with any control condition or another social support intervention for treatment of people with type 2 diabetes from LMICs and those from racial and ethnic minoritized groups in HICs. The primary outcome was the mean change in hemoglobin A1c (HbA1c), presented as mean differences (MDs) and 95% confidence intervals (95% CIs) estimated by the random-­effects model. Treatment rankings were summarized as surface under the cumulative ranking curve (SUCRA) values. Network meta­-regression was done to investigate whether the results were associated with study characteristics. Subgroup analysis was done according to socioeconomic development. From 2885 publications, 25 trials (4180 participants) were included. These trials compared four categories of individual-based interventions provided by peers with diabetes, community health workers, health professionals, or health professionals assisted by trained laypersons, one family-based intervention implemented by health professionals, and usual care. The mean baseline HbA1c was 73 mmol/mol (8.8%). The mean age was 55.1 years (SD 4.8). The mean intervention duration was 7.1 months (SD 4.5). Family-based intervention implemented by health professionals (mean rank 1.0, SUCRA 99.9) was more effective than individual-based intervention by health professionals (mean rank 2.4, SUCRA 71.8) (MD -6 mmol/mol [-0.6%], 95% CI -10 mmol/mol to -2 mmol/mol [-0.9% to -0.2%]), individual-based intervention by peers (mean rank 3.3, SUCRA 53.7) (MD -8 mmol/mol [-0.7%], 95% CI -12 mmol/mol to -4 mmol/mol [-1.1% to -0.3%]), individual-based intervention by community health workers (mean ranks 3.8, SUCRA 43.9) (MD -8 mmol/mol [-0.8%], 95% CI -13 mmol/mol to -4 mmol/mol [-1.2% to -0.4%]), and individual-based intervention by health professionals assisted by trained laypersons (mean rank 4.6, SUCRA 28.3) (MD -10 mmol/mol [-0.9%], 95% CI -16 mmol/mol to -4 mmol/mol [-1.5% to -0.4%]). Network meta-­regression analyses showed that prespecified study characteristics did not have a significant effect. Subgroup analysis for socioeconomic development indicated no significant difference. Family-based interventions delivered by health professionals may improve glycemic control (low- to very-low-certainty evidence). Individual-based interventions by health professionals are likely to improve glycemic control (moderate-certainty evidence). Methodologically rigorous studies are still required.