Scaling‐up evidence‐based obesity interventions: A systematic review assessing intervention adaptations and effectiveness and quantifying the scale‐up penalty

Abstract

Maximizing the benefits of investments in obesity research requires effective interventions to be adopted and disseminated broadly across populations (scaled-up).However, interventions often need considerable adaptation to enable implementation at scale, a process that can reduce the effects of interventions. A systematic review was undertaken for trials that sought to deliver an obesity intervention to populations on a larger scale than a preceding randomized controlled trial (RCT) that established its efficacy. Ten scaled-up obesity interventions (six prevention and four treatment) were included. All trials made adaptations to interventions as part of the scale-up process, with mode of delivery adaptations being most common. A metaanalysis of body mass index (BMI)/BMI z score (zBMI) from three prevention RCTs found no significant benefit of scaled-up interventions relative to control (standardized mean difference [SMD] = 0.03; 95% CI, −0.09 to 0.15, P = 0.639 − I 2 = 0.0%). All four treatment interventions reported significant improvement on all measures of weight status. Pooled BMI/zBMI data from prevention trials found significantly lower effects among scaled-up intervention trials than those reported in prescale-up efficacy trials (SMD = −0.11; 95% CI, −0.20 to −0.02, P = 0.018 − I 2 = 0.0%). Across measures of weight status, physical activity/sedentary behaviour, and nutrition, the effects reported in scaled-up interventions were typically 75% or less of the effects reported in pre-scale-up efficacy trials. The findings underscore the challenge of scaling-up obesity interventions.

Health professional-delivered obesity prevention interventions during the first 1,000 days: A systematic review of external validity reporting

“…While most interventions that are scaled up need to be adapted to fit the delivery context, knowing information about dose-response and the mechanism of intervention effects is essential in informing adaptions so that effectiveness of the intervention is not lost. The recent systematic review by McCrabb and colleagues highlights the decreased intervention effects when obesity interventions are scaled up -they found that effects on weight status, physical activity/sedentary behaviour, and nutrition reported in scaled-up interventions were typically 75% or less of the effects reported in pre-scale-up efficacy trials 9 .…”

“…Appraising scalability prior to investment is vital 8,9 . Scalability is defined by the World Health Organization as 'the deliberate effort to increase the impact of successfully tested health interventions so as to benefit more people and to foster policy and program development on a lasting basis' 10 .…”

Future directions to prevent obesity within the context of the Global Syndemic

“…This study found that community leaders willing to build new relationships and take risks to change existing practice and redesigning health promotion with a community development focus offered important levers for meaningful change. McCrabb et al found that interventions tested at community level often need considerable adaptation to be implemented at scale, which may reduce the effectiveness of interventions. A systematic review of scaled‐up obesity interventions (six prevention and four treatment) showed that the effects reported in scaled‐up interventions related to weight status, physical activity, sedentary behavior, and nutrition were typically 75% or less of the effects reported in efficacy trials before being scaled up for populations.…”

Co-Designing an Intervention to Prevent Overweight and Obesity among Young Children and Their Families in a Disadvantaged Municipality: Methodological Barriers and Potentials

“…The latest reviews found that the effects of interventions to prevent overweight and obesity among preschool children led to small significant effects [2][3][4]. Nevertheless, translating and upscaling randomized controlled trials (RCTs) into real-world settings does not necessarily replicate this effect [5,6]. It is known that involvement of parents in preventive interventions is often challenged by recruitment and retention [7].…”