Limitations
obesity, comorbidity, weight loss, Comorbidity
OBESITY, DISEASE, REMISSION, CARDIOVASCULAR DISEASE
As is typically the case with RCT-based cost-utility analyses, long-term health effects beyond the duration of the MERIT study were extrapolated, introducing uncertainty into our analysis. Whilst durable total body weight loss over the longer term with ESG has been shown in a previous 5-year prospective cohort study by Sharaiha et al [There were insufficient data from the MERIT study for the BMI ranges informing the healthy weight and overweight health states from which to calculate health state utility values. As such, the health state utility values for these health states were informed by values reported by Stephenson et al [There were also insufficient data from the MERIT study from which to directly estimate mortality and rates of obesity-related comorbidities. As shown by the one-way sensitivity analysis and our scenario analysis using unadjusted general population mortality rates, the impact of BMI on mortality risk was not a key driver of cost effectiveness in our model. Comorbidity rates sourced from the literature were limited in that for some of the comorbidities included in the model, prevalence rates were reported for BMI ranges spanning multiple model health states. This approach also did not allow us to explicitly model the more complex and multifactorial relationship between bariatric procedure induced weight loss and disease remission among people with pre-existing comorbidities at baseline. Additionally, cardiovascular disease is an important obesity-related comorbidity, but we did not identify any suitable data from the literature that were both compatible with our model structure and generalisable to the UK setting. Many other conditions have also been shown to be independently associated with increases in BMI [Lastly, given our model population was already restricted to the MERIT class II obesity subgroup (