Evaluating the effectiveness of community health worker interventions on glycaemic control in type 2 diabetes: a systematic review and meta-analysis

Background: Interventions with community health workers, trained to provide basic medical education and holistic support, have been used to enhance type 2 diabetes outcomes in various settings. Evidence of their effectiveness is poor because of variations in intervention design and duration. We did a systematic review of randomised trials evaluating the effectiveness of community health worker interventions integrated into conventional care to improve glycaemic control in adults with diabetes.

Methods: In this systematic review and meta-analysis, we included randomised trials of community health worker interventions of at least-12 months' duration in adults with type 2 diabetes that compared HbA_1c levels with usual care. We searched Ovid MEDLINE, the Cochrane Central Register of Controlled Trials, CINAHL and the Web of Science Core Collection for studies published in English between Jan 1, 2000, and March 1, 2023, for studies containing "community health worker" or "lay health worker", and "type 2 diabetes". We extracted both qualitative and quantitative data to assimilate community health worker intervention characteristics. We did a meta-analysis comparing changes in HbA_1c levels from baseline between intervention groups and usual care groups. To be included in the meta-analysis, studies had to have HbA_1c values at baseline and after 12 months and a patient dropout rate of less than 25% at 12 months follow-up. The main outcome was the mean weighted difference of % change in HbA_1c after at least 12 months, assessed using Revman, the inverse variance-weighted average model (IVW). Quality was assessed using the Cochrane Rob2 tool.

Findings: Seven of 86 retrieved studies were eligible for inclusion; six studies were conducted in the USA and one study in Indigenous Australia. Participants in all studies were recruited from Latino, African American and Indigenous Australian ethnic minority groups. The meta-analysis of six studies including 1280 participants (mean age 52·6 years [SD 3·68]; 832 [65%] female and 448 [35%] male) showed a significant improvement in HbA_1c level at 12 months follow-up, with a mean weighted difference of 0·5% (95% CI 0·31-0·68) in the community health worker intervention group (p<0·0001), that reached the generally accepted minimal clinically important difference (≥0·5%). Outcome heterogeneity was low.

Interpretation: Community health worker interventions showed a significant reduction in HbA_1c level adjunct to usual care, but caution must be taken given the point effect estimate is only just the MCID, and the true effect could be smaller. Given the current resource constraints faced by primary care, community health worker interventions could be innovative in informing the primary and secondary management of diabetes care in UK practice. A cost-effectiveness analysis of these interventions is required before implementation in routine diabetes care can be recommended.

Funding: None.