title: Gastric bypass is a cost-saving procedure: results from a comprehensive Markov model.
abstract: BACKGROUND
  Obesity is a growing public health problem in industrialized countries and is directly and indirectly responsible for almost 10% of all health expenditures. Bariatric surgery is the best available treatment, however, associated with important economical expenditures. So, cost-effectiveness analysis of the available surgical options is paramount.
  
  
  METHODS
  We developed a Markov model for three different strategies: best medical management, gastric band, and gastric bypass. The Markov model was constructed to allow for the evaluation of the impact of several obesity-related comorbidities. The results were derived for a representative population of morbidly obese patients, and subgroup analyses were performed for patients without comorbidities, patients with diabetes mellitus, different age, and body mass index (BMI) groups. Cost-effectiveness analysis was performed accounting for lifetime costs and from a societal perspective.
  
  
  RESULTS
  Gastric bypass is a dominant strategy, rendering a significant decrease in lifetime costs and increase in quality-adjusted life years (QALYs). Comparing with the best medical management, in the global population of patients with a BMI of > 35 kg/m2, gastric bypass renders 1.9 extra QALYs and saves on average 13,244€ per patient. Younger patients, patients with a BMI between 40 and 50 kg/m2, and patients without obesity-related diseases are the ones with a bigger benefit in terms of cost effectiveness.
  
  
  CONCLUSIONS
  Gastric bypass surgery increases quality-adjusted survival and saves resources to health systems. As such, it can be an important process to control the ever-increasing health expenditure.
authors: Department of Surgery, Faculty of Medicine, University of Porto, Porto, Portugal. gilrfaria@gmail.com
authors: Gil R
authors: GR
authors: Faria
authors: John R
authors: JR
authors: Preto
authors: José
authors: J
authors: Costa-Maia
mesh_terms: D000328:Adult; D015992:Body Mass Index; D015897:Comorbidity; D003362:Cost-Benefit Analysis; D003924:Diabetes Mellitus, Type 2 / Q000191:economics* / Q000601:surgery; D005260:Female; D015390:Gastric Bypass / Q000191:economics*; D015391:Gastroplasty / Q000191:economics*; D005102:Health Expenditures; D006801:Humans; D008297:Male; D008390:Markov Chains; D018803:Models, Economic; D009767:Obesity, Morbid / Q000191:economics* / Q000601:surgery; D011174:Portugal; D019057:Quality-Adjusted Life Years