The Healthy Living Partnerships to Prevent Diabetes study: 2-year outcomes of a randomized controlled trial

Background: Since the Diabetes Prevention Project (DPP) demonstrated that lifestyle weight-loss interventions can reduce the incidence of diabetes by 58%, several studies have translated the DPP methods to public health-friendly contexts. Although these studies have demonstrated short-term effects, no study to date has examined the impact of a translated DPP intervention on blood glucose and adiposity beyond 12 months of follow-up.

Purpose: To examine the impact of a 24-month, community-based diabetes prevention program on fasting blood glucose, insulin, insulin resistance as well as body weight, waist circumference, and BMI in the second year of follow-up.

Design: An RCT comparing a 24-month lifestyle weight-loss program (LWL) to an enhanced usual care condition (UCC) in participants with prediabetes (fasting blood glucose=95-125 mg/dL). Data were collected in 2007-2011; analyses were conducted in 2011-2012.

Setting/participants: 301 participants with prediabetes were randomized; 261 completed the study. The intervention was held in community-based sites.

Intervention: The LWL program was led by community health workers and sought to induce 7% weight loss at 6 months that would be maintained over time through decreased caloric intake and increased physical activity. The UCC received two visits with a registered dietitian and a monthly newsletter.

Main outcome measures: The main measures were fasting blood glucose, insulin, insulin resistance, body weight, waist circumference, and BMI.

Results: Intent-to-treat analyses of between-group differences in the average of 18- and 24-month measures of outcomes (controlling for baseline values) revealed that the LWL participants experienced greater decreases in fasting glucose (-4.35 mg/dL); insulin (-3.01 μU/ml); insulin resistance (-0.97); body weight (-4.19 kg); waist circumference (-3.23 cm); and BMI (-1.40), all p-values <0.01.

Conclusions: A diabetes prevention program administered through an existing community-based system and delivered by community health workers is effective at inducing significant long-term reductions in metabolic indicators and adiposity.