Evaluation of a pilot for use of obesity medications outside hospital settings

Background: New weight loss drugs such as Semaglutide (Wegovy) and Tirzepatide (Mounjaro) offer more effective obesity treatment when combined with behavioural interventions. These drugs should be prescribed within Tier 3 specialist weight management services (T3SWMS), which lack nationwide availability and sufficient capacity for eligible individuals.

NHS England (NHSE) is thus piloting three new service models to access weight loss drugs, necessitating a comprehensive evaluation to guide future rollout.

Aim: 1) Evaluate the feasibility, acceptability, safety, effectiveness, and cost-effectiveness of new models for providing weight loss drugs across socio-demographic groups, 2) Provide insights to guide future national rollout of service models, promoting equitable access to weight loss drugs. Objectives:

1. Map key characteristics of pilot services, including geography, socio-demographics, model types, and stakeholders. 2. Identify socio-demographic factors associated with rates of referral, uptake, and completion of pilot models.

3. Evaluate short-term clinical effectiveness, cost-effectiveness, and safety across models, considering socio-demographic differences. 4. Model long-term health outcomes and costs for service models. 5. Explore potential cost-effectiveness of implementation initiatives to increase service uptake.

6. Investigate feasibility and safety of new service models, considering staff needs, training, impact on primary care, and implications for the wider weight management tiered system.

7. Assess acceptability and user experience of service models, including behavioural support components, across socio-demographic groups.

8. Develop insights on the most acceptable, effective, safe, and cost-effective models for different socio-demographic groups, articulated through a preliminary logic model. 9. Identify primary care training needs and resources for future rollout. 10. Identify key criteria for a definitive evaluation of future rollout of new service models.

Methods, Timelines and Anticipated Impact and Dissemination: The project will run from April 2024 to March 2027, aligning with the pilot launch. It employs mixed methods across five work packages (WPs):

• WP1 (Months 1-36, objective 1): Project management, PPIE, stakeholder engagement, and mapping key information about pilot WM services to support subsequent WPs.

• WP2 (Months 6-30, objectives 2-5): Identify socio-demographic factors associated with service utilization. Evaluate clinical and cost-effectiveness and safety across models and socio-demographic groups using a target trial framework. Data collection includes NHSE electronic clinical data and surveys with people living with obesity (PLWO), service providers, and commissioners.

• WP3 (Months 6-30, objectives 6,7): Employ qualitative methods at three case study sites (representing each service model) to assess feasibility, acceptability, safety, and behaviour change factors in different socio-demographic groups. Supported by a 'researcher in residence' model and PPIE community researchers.

• WP4 (Months 6-36, objective 8): Integrate data across WPs 2&3 with mixed methods analysis. Use a triangulation protocol with key stakeholders to inform a logic model mapping service commissioning and setup to patient outcomes.

• WP5 (Months 1-36, objectives 9,10): Dissemination, outputs, and anticipated impact. Inform NHSE to guide roll-out and future evaluation, emphasizing access across socio-demographic groups.