Long-Term Impact of a Community Health Worker Intervention on Diabetes Control in American Samoa

Diabetes Care in American Samoa (DCAS) was a randomized controlled trial of a 12-month intervention facilitated by community health workers (CHWs) that demonstrated improved HbA1c levels compared with usual care at trial completion. We sought to evaluate the long-term impact of this intervention on diabetes control.

We retrospectively collected HbA1c measurements from medical records of DCAS participants (n = 268). The study group received the intervention during the trial, and the control group received the intervention after the trial. We used mixed-effects longitudinal regression models to assess change in HbA1c within each trial arm during 3 time periods: DCAS (12 months of the study group's intervention), the first year after DCAS (control group's intervention), and the second year after DCAS. Models were adjusted for baseline characteristics that differed significantly for participants with a low number of HbA1c measurements from those with a high number of HbA1c measurements.

After adjustment for confounders, the experiment group experienced a decrease in HbA1c of 0.28 units per year (95% confidence interval [CI], -0.64 to 0.07) during DCAS (intervention). HbA1c decreased by 0.88 units per year (95% CI, -1.31 to -0.45) during the year after the intervention. No significant change was observed the following year. HbA1c of the control group did not significantly change during DCAS (usual care) but decreased by 1.31 units per year (95% CI, -1.72 to -0.91) during its intervention. During the year after the control group's intervention, HbA1c increased by 1.18 units per year (95% CI, 0.42 to 1.93).

Both groups had initial improvements in glycemic control, but HbA1c later plateaued or increased. These results suggest that time-limited CHW programs improve diabetes control in the short term, but ongoing programs are needed for sustained impact.