Australia has one of the highest levels of obesity amongst OECD countries. Bariatric surgery is the most effective therapy for long-term weight loss amongst persons with morbid obesity. However, weight loss is a highly variable outcome due to a range of factors, including comorbidity, socioeconomic status, and genetic makeup. Common allele homozygotes for FTO rs9939609 have been found to be associated with more consistent weight loss over the long term post-bariatric surgery. This study will examine the cost-effectiveness of genetic screening for FTO compared to no screening in patients with morbid obesity.
A microsimulation model, NCDMod, will be used for an economic evaluation. We will compare both health outcomes and costs for Scenario 1 where bariatric surgery was offered to those aged 20-64 with BMI>40 and Scenario 2 which offered bariatric surgery to those aged 20-64 with BMI>40 but testing positive to FTO. Key health outcomes were the reduced number of persons with obesity, diabetes diagnoses, shifts in healthcare costs between 2015 and 2025; and the ICER of cost per obesity case averted.
Approximately 20,000 persons amongst the 320,000 eligible were simulated to undergo bariatric surgery under each scenario. The genetic screening group (Scenario 2) had 11,000 less persons with obesity in the cohort 10 years post-surgery than the no screening group. Further, the genetically screened group experienced 300 less CVD events across 10 years post-surgery and had similar levels of diagnosed diabetes. The healthcare costs per person per annum was $650 less for the screened group. Genetic screening of eligible patients for bariatric surgery dominated no screening because its effectiveness was higher and its costs lower.
In the move to personalised medicine, this study shows that genetic screening in patients with morbid obesity may assist in patient/clinician decision making regarding bariatric surgery.