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

Results need to be stratified by baseline presence or absence of type 2 diabetes mellitus (T2DM), baseline presence or absence of atherosclerotic cardiovascular disease (ASCVD) and whether the population is living with overweight or obesity at baseline (that is, reported separately and not combined – see table 1 for model stratification for presenting cost effectiveness results). For the definition of overweight and different classes of obesity, see table 2 on BMI categories by ethnic group.

Only the stratum or strata relevant to the intervention's proposed target population need be modelled.

When this population is more specific than any of the strata defined in table 1, only that specific population needs to be modelled. (required)

Further subgrouping should be undertaken to reflect differences in the baseline risk of events, treatment effect, and to capture existing thresholds for bariatric procedures and medications – see paragraphs 1.3 to 1.5. (recommended)

The population in strata 5 to 8 should be further subgrouped by body mass index (BMI) category (obesity class 1, obesity class 2, obesity class 3). The categorisation should be done by ethnicity when individual patient data about this is available as described in table 2 on BMI categories by ethnic group (source: NICE CKS: obesity diagnosis, identification and classification). (recommended)

For strata containing people without either T2DM or ASCVD, subgrouping by type or number of obesity-related comorbidities (such as dyslipidaemia, hypertension, metabolic dysfunction-associated steatotic liver disease (MASLD), obstructive sleep apnoea and non-diabetic hyperglycaemia [also referred to as 'pre‑diabetes'] or metabolic syndrome) should be undertaken. (recommended)

For strata containing people with T2DM or ASCVD or T2DM and ASCVD, subgrouping by presence or absence of chronic kidney disease (CKD) or chronic heart failure (CHF) should be undertaken. (recommended)

Estimate baseline patient characteristics for each strata, such as age, sex, and weight, from real-world evidence representative of the NHS population in England. (required)

A sensitivity analysis should be conducted where baseline patient characteristics for each strata such as age, sex and weight, are estimated from trial data. (recommended)