One-year effects of a group-based lifestyle intervention in adults with type 2 diabetes: A randomized encouragement trial.

Aims: To estimate the real-world effects of offering a group-based lifestyle intervention (GLI) to adults with diabetes.

Methods: This randomized encouragement trial included adult primary care patients in metropolitan Chicago with type 2 diabetes and body mass index ≥24 kg/m. Participants were randomized to standard care (brief dietary and lifestyle counseling) or standard care plus being encouraged, but not required, to participate in a free-of-charge GLI offered by the YMCA. The GLI was a group-based adaptation of the Look AHEAD lifestyle intervention.

Results: Of 331 participants, 167 were randomized to standard care and 164 to the GLI encouragement arm. About one third of participants were non-Hispanic White (34.4%). In the GLI arm, 75 (45.7%) attended ≥1 GLI visits. In the primary intention-to-treat analysis, the effect of GLI encouragement was 0.95% weight loss at six months (95% confidence interval [CI], 0.13-1.77%; P = 0.02), and 1.20% weight loss at 12 months (95% CI, 0.05-2.36%; P = 0.04). At 12 months, there was a 0.30% (3.3 mmol/mol) reduction in hemoglobin A1c, but this result did not achieve statistical significance (P = 0.054). In instrumental variable analysis estimating effects among the subgroup of participants who attended any GLI visits, the effect of GLI attendance was 2.30% weight loss at six months (95% CI, 0.30-4.30%; P = 0.02), and 2.07% weight loss at 12 months (95% CI, 0.25-3.88%; P = 0.02). We detected no significant blood pressure or cholesterol effects.

Conclusions: Among adults with type 2 diabetes, a group-based lifestyle intervention in a community-based setting achieved modest weight loss at 6 and 12 months.

Clinical Trial Registration: ClinicalTrials.gov Identifier NCT01435603.