Diabetes prevention in the Caribbean using lifestyle intervention and Metformin escalation (LIME): results from a quasi-experimental study.

BACKGROUND: The Caribbean region suffers from a high burden of diabetes and diabetes-associated mortality. Despite the evidence for diabetes prevention programs, there have been very few such initiatives in the region. To address this gap, we describe the effectiveness and implementation of the Lifestyle Intervention and Metformin Escalation (LIME) Clinical Trial in reducing the risk of diabetes among individuals with pre-diabetes in the Caribbean. METHODS: LIME is a quasi-experimental pre-post study that took place between 2018 and 2021. LIME recruited individuals with high-risk pre-diabetes (hemoglobin A1c (HbA1c) between 6.0 and 6.4%) across clinical sites in Barbados, Trinidad and Tobago, Puerto Rico, and the US Virgin Islands. Eligible participants were enrolled in a 6-week lifestyle modification workshop. Six months later, individuals who did not lose at least 5% of their bodyweight or had an HbA1c of 6% or higher were prescribed metformin medication. The primary outcome was a change in HbA1c at 6- and 12-months. Paired t-test and McNemar's test were used to examine change in primary outcome. Implementation outcomes of reach, adoption, and implementation fidelity were assessed using programmatic data. RESULTS: Of 914 individuals screened, 211 (23%) had high-risk pre-diabetes. Of those, 114 enrolled in the study (54% Reach). At the 6-month follow-up, there was a significant reduction in average HbA1c from 6.19% to 5.95% (p < 0.001), average weight from 86.7 kg to 85 kg (p < 0.001), with a reduction in added sugar intake from 7.3 tsp/day to 3.8 tsp/day (p < 0.0001) but no significant change in physical activity level or fruit and vegetable intake. Reduction in HbA1c (6.19% to 5.67%, p < 0.0001) and weight (85.1 kg to 83.7 kg, p = 0.0149) was maintained at 12 months. Trained facilitators variably engaged in leading workshops (adoption 25%-100%), and were 100% adherent to the protocol (fidelity). CONCLUSION: LIME is an effective diabetes prevention intervention for individuals with pre-diabetes in the Caribbean. Future work should investigate approaches to improve reach (eligible participant engagement) and adoption (participation of trained facilitators), and report on cost-effectiveness to inform scale-up of the intervention. TRIAL REGISTRATION: clinicaltrials.gov NCT03258723 (23/08/2017).