Online group programs aid weight loss but face hurdles

Digital group interventions offer a scalable solution to severe obesity, but overcoming barriers like internet access and participant engagement is key to success.

Clinical Research: The effectiveness and usability of online, group-based interventions for people with severe obesity: a systematic review and meta-analysis. Image Credit: Gecko Studio / Shutterstock

In a recent study published in the International Journal of Obesity, researchers in the United Kingdom evaluated the effectiveness, usability, and barriers of online group-based interventions for adults with severe obesity.

Background

Obesity poses significant public health challenges, increasing the burden on healthcare services and limiting access to treatment. It is strongly linked to numerous health conditions, including type 2 diabetes, cardiovascular disease, and cancer. Severe obesity exacerbates these risks, highlighting the need for accessible interventions.

Group-based approaches, effective for weight management and fostering social support, can reduce service demands but face logistical constraints. The journal highlighted that traditional face-to-face interventions often result in long wait times and limited accessibility, particularly in underserved regions.

Digital interventions could mitigate these issues while providing a scalable solution. Digital delivery could address barriers like travel and time, enhancing accessibility. While digital and group-based interventions have been studied separately, further research is needed to synthesize evidence and determine the effectiveness of integrating these approaches.

About the study

The study was structured using the population, intervention, comparator, outcome, and study type (PICOS) framework to define the scope of the research and ensure systematic methodology. The reporting adhered to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines.

The eligibility criteria were defined to include studies examining online, group-based interventions for adults with severe obesity (body mass index (BMI) ≥ 35 kg/m²). Interventions had to be primarily group-based, involving three or more participants, and delivered via technology.

Outcomes could include behavior changes, anthropometric measures, or other health-related metrics. Studies focusing on children, interventions for non-obesity-related conditions, or those with a mean BMI < 35 kg/m² were excluded.

A comprehensive search was conducted across five databases, including MEDLINE, Embase, and Web of Science, excluding grey literature to prioritize peer-reviewed studies. Unlike the protocol, APA PsycINFO and ProQuest Dissertations and Theses databases were not searched due to unavailability.

The search strategy combined key terms related to online delivery, group-based interventions, and severe obesity. Due to delays in screening and analysis, the searches were updated in 2022 and 2024. Duplicate removal and screening were conducted using systematic review software, with disagreements resolved by consensus.

Reviewers performed data extraction and quality appraisal independently, using pre-determined criteria to capture intervention details, participant demographics, and outcomes. The risk of bias was assessed using the Cochrane Risk of Bias 2 (RoB 2) tool for randomized trials and the Mixed-Methods Appraisal Tool (MMAT) for other methodologies.

Descriptive analysis and narrative synthesis were conducted to summarize the findings. A meta-analysis assessed the effect of interventions on weight change, employing a random-effects model due to heterogeneity.

Results were presented in a forest plot, and publication bias was evaluated using Egger’s test. The study also examined the relationship between intervention characteristics and participant engagement and identified key facilitators and barriers.

Study results

From the initial two search rounds conducted in March 2021 and April 2022, a total of 3,137 articles were retrieved across five databases. Following the removal of 1,183 duplicates using EndNote X9, the titles and abstracts of the remaining articles were screened, leaving 49 eligible for further review. At this stage, additional records, such as trial registrations and conference abstracts, were sought.

Thirteen full reports could not be retrieved, leaving 36 full-text articles for evaluation. Ultimately, 17 papers, including 12 unique studies, were included. In cases where multiple papers reported on the same study, data were extracted separately due to differences in participant numbers or subgroup analyses.

A third search in May 2024 yielded 952 additional articles. After removing duplicates, 635 references were screened, and 35 underwent full-text review. Three further papers were included, resulting in a total of 20 papers describing 15 distinct studies.

These studies, conducted between 2005 and 2023, reported sample sizes ranging from 14 to 481 participants, with analyzed sample sizes for online, group-based interventions ranging from 11 to 418. Across the studies, most participants were female, with baseline BMIs ranging from 35.2 to 49.2 kg/m². The predominance of female participants highlights a gender imbalance, potentially limiting the generalizability of findings to male populations.

The interventions varied considerably in design. Group sizes ranged from 3 to 43 participants, with session numbers spanning from 6 to 47. Session lengths, reported in 60% of the studies, ranged from 45 to 75 minutes, while intervention durations were typically six months, though some extended to 12 or 18 months. Only seven interventions were based on a theoretical framework, including Social Cognitive Theory, Self-Determination Theory, and technology acceptance models.

Weight outcomes were the primary focus, reported in 12 of the 15 studies. While less than half demonstrated significant differences in weight loss compared to controls, several studies highlighted additional metrics, including BMI, waist-to-hip ratio, and fat percentage. Other reported outcomes included physical activity, dietary behaviors, mental health, and quality of life.

Engagement levels varied, with completion rates ranging from 30% to 95%. Tailored approaches, such as interactive forums or technical support, were shown to enhance engagement, though barriers such as internet accessibility and unfamiliarity with group members persisted.

Older adults and individuals from marginalized communities face unique challenges, such as limited digital literacy and internet access. Acceptability and usability were generally positive, though technical issues and concerns about sharing information in virtual settings were noted.

The meta-analysis of four studies revealed a small-to-moderate effect of online, group-based interventions on weight loss compared to standard care. Statistical details, such as a standardized mean difference of -0.428 and a 95% confidence interval of -0.69 to -0.17, highlighted this effect.

Conclusions

To summarize, fifteen studies examined the impact of online, group-based weight management interventions for individuals with severe obesity (BMI ≥ 35 kg/m²). These interventions varied in platform type, group size, session frequency, and duration, typically lasting six months with one-hour sessions.

Most studies observed weight loss among participants, and a meta-analysis indicated a small-to-moderate effect of these interventions compared to no treatment. However, findings were limited by small sample sizes, a predominance of female participants, and inconsistent examination of behavioral outcomes, particularly dietary changes.

Weight loss outcomes varied significantly by intervention design, with financial incentives and tailored feedback showing the most promise. Barriers such as digital literacy challenges, lack of social connection, and technical issues hinder engagement.

The study recommends practical strategies, such as consistent facilitators, session reminders, advanced sharing of session content, and team-building activities, to enhance group cohesion and engagement.

Future research should focus on optimizing these interventions, including exploring subgroup-specific benefits and developing strategies to address barriers, particularly for underserved populations.