LAUSR

Objectives This study helps to fill the existing research gap related to participant engagement in behavioural interventions and diabetes management. We examined type 2 diabetes control over time among Mexican Americans by level of engagement in a chronic care management (CCM) program that included community health worker (CHW)-delivered multilevel interventions. The programme complemented clinical care and promoted behaviour changes to improve diabetes self-management. Design Quasiexperimental study. Setting The study was implemented in the Rio Grande Valley region in the USA. Recruitment was conducted in clinics and community events. All other visits were provided in participant homes and community locations. Participants 5649 adults (aged ≥18 years) with poorly controlled type 2 diabetes who enrolled in a community-delivered CCM programme between September 2013 and 2018. Interventions The intervention comprised two components: CHW home visits conducted every 3 months and diabetes self-management education (DSME) classes provided in community locations. Primary outcome measures The primary outcome was haemoglobin A1c (HbA1c) measured at baseline every 3 months for up to 24 months. We first examined changes in HbA1c levels over time. The number of completed CHW and DSME encounters was used to classify participants into engagement groups—high engagement defined as ≥10 encounters (n=2952); low engagement defined as 1–9 encounters (n=2697). We used univariable and multivariable longitudinal linear regression models with a generalised estimating equation method. We tested interactions between engagement groups and time. Results Participants’ mean HbA1c decreased from 10.20% at baseline to 8.93% (p<0.0001) at 3 months, remaining stable thereafter. Changes in HbA1c were statistically different between the engagement groups. High engagement participants had lower HbA1c levels over the first 15 months of the follow-up period compared with low engagement participants, as compared at 3 months (−0.44%, 95% CI −0.57% to –0.31%; p<0.0001), 6 months (−0.31%, 95% CI −0.43% to –0.14%; p<0.0001), 9 months (−0.27%, 95% CI −0.42% to –0.13%; p=0.0001), 12 months (−0.23%, 95% CI −0.37% to –0.08%; p=0.0025) and 15 months (−0.32%, 95% CI −0.54% to –0.10%; p=0.0040). At months 18, 21 and 24, the HbA1c differences were not statistically significant (18 months: −0.34%, 95% CI −0.77% to 0.08%; p=0.1086; 21 months: −0.22%, 95% CI −1.00% to 0.56%; p=0.5721; 24 months: −0.42%, 95% CI −1.38% to 0.55%; p=0.3966). Conclusions Higher engagement in the CCM programme delivered by CHWs and coordinated with clinical care was associated with beneficial improvements in type 2 diabetes control, but both engagement groups showed strong improvements.