Disease-specific reference case extension: management of overweight and obesity in adults

Include incremental costs associated with assessment for eligibility for any intervention, such as suitability for bariatric surgery procedures. (required)

Include costs of complications, including the costs of re-operation and re-intervention for bariatric procedures. (required)

Include the following implementation costs:

• supply chain costs associated with medicines, if applicable (required)

• capital investment costs associated with bariatric procedures, if applicable. (required)

For behavioural interventions, whether as a comparator or used concomitantly with other interventions, ensure resource use reflects current NHS practice in the base case. In a sensitivity analysis, base this on resource use associated with the relevant trials. (required)

Health state and event costs, including costs associated with treatment or procedure-related adverse effects, should align with clinical practice and, when appropriate, be specific to the population stratum and be sourced from the NHS in England. (recommended)

Resource use for all health states should capture use of mental healthcare services, because this is important for all morbidities. (recommended)

The best source for background costs is a single dataset that controls for weight, comorbidity and other variables such as age and sex. If that is not available then, to avoid double-counting, ensure that either the source study for weight-related costs is controlled for comorbidities or the source study for comorbidity-related costs is controlled for weight. (required)

Resource use for modelled comorbidities should consider duration of comorbidity, with different costs for managing newly-diagnosed comorbidities versus those for managing established comorbidities. (recommended)

For people with type 2 diabetes mellitus (T2DM), management and complication costs from cohort studies should be used. For example, the UK Prospective Diabetes Study (UKPDS), which include the cost of consultations, visits, admissions and procedures associated with diabetes-related complications. (recommended)