Randomized trial comparing group size of periodic in-person sessions in a remotely delivered weight loss intervention

Abstract

BackgroundFew randomized studies have examined differential effects of group size in behavioral weight control, especially in hybrid programs that include Internet treatment approaches.MethodsRandomized controlled trial (n = 195) comparing a 4 month hybrid internet weight loss program coupled with monthly face to face groups of 100 persons (Large Group, LG; 1 group) or to the same approach with monthly groups of 20 persons (Small Group, SG; 4 groups). Repeated-measures mixed-model analysis with age and race as covariates were used to estimate primary (weight) and secondary outcomes, and to test group differences in change over time.ResultsThe sample was 46.3 years old ±10.4, 90.3% female, and 51.9% non-white, with BMI 37.9 ± 8.4 kg/m2. Participants in the LG were more likely to return for the 4-month assessment visit than those in the SG (p = 0.04). Participants randomized to both the LG and SG conditions experienced significant WL over time (no between group difference: −4.1 kg and −3.7 kg, respectively) and weight loss was positively associated with attendance at monthly meetings and logins to the website. Satisfaction with the program was high and similar in both groups (94.4% reported that they were “satisfied” or “very satisfied”).ConclusionsUsing a hybrid approach of in-person and online weight loss interventions may be an effective way to reach larger and more diverse populations. Delivering the face to face component of the intervention in groups larger than those traditionally delivered (20–25 people) could increase the cost-effectiveness of group-based behavioral weight loss interventions.Clinical trials registration number NCT01615471. Registered June 6, 2012. Registered retrospectively.

New research directions on disparities in obesity and type 2 diabetes

“…The literature on effectiveness of remotely delivered approaches to treat obesity is promising, but the effects specific to minority populations are understudied. 64 A trial with predominantly Hispanic women participating in the Special Supplemental Nutrition Program for Women, Infants, and Children (WIC) found that an internet-based weight loss program in addition to WIC resulted in significantly greater weight loss over 12 months compared with the WIC program alone. 63 Few studies had 50% or more participants from racial or ethnic minority groups or outcomes reported by race.…”

“…63 Subsequent studies have demonstrated the acceptability and feasibility of remotely delivered obesity programs and suggest strategies to enhance the recruitment of African Americans and Hispanics. 64 A trial with predominantly Hispanic women participating in the Special Supplemental Nutrition Program for Women, Infants, and Children (WIC) found that an internet-based weight loss program in addition to WIC resulted in significantly greater weight loss over 12 months compared with the WIC program alone. 65 Intervening on neighborhood contexts Physical, or built, environments can profoundly shape health and health behaviors related to eating and physical activity.…”

“…Additionally, greater use of telephone or digital technology to deliver or tailor interventions 64 was discussed as having a high potential because many high-risk populations are heavy users of web or cell technologies. 124 However, limitations on broadband access were noted as a potential issue to be resolved for rural populations.…”

Racial Differences in Weight Loss Mediated by Engagement and Behavior Change

“…A 4-month randomized controlled trial (N=195), fully described elsewhere and based on the Diabetes Prevention Program, provided data for this analysis. 9 Briefly, eligible partici-PA. Both groups received the same Internet components: weekly automated tailored feedback, self-monitoring tools (online or paper calorie tracking diary), tailored lessons and tools for problem-solving dietary and PA barriers, video resources, exercise planning tools (online scheduler and progression plan), and a message board for social support.…”

“…Reasons for the weight loss disparity are not well understood. Mixed findings on racial differences in dietary and PA changes during BWI, 8,9 difficulty recruiting and retaining minorities, and a lack of conducting or reporting such analyses contribute to the knowledge gap. 7,10 More evidence is needed to understand and reduce the racial weight loss disparity.…”