Impact of Bariatric Surgery on Life Expectancy in Severely Obese Patients With Diabetes
I read with great interest your recent article on the impact of bariatric surgery on life expectancy in severely obese patients with diabetes, a subgroup of the metabolic/surgery population.1 Your method of statistical approach by Markov modeling is powerful. The answer to the question you pose is quite precise: total life expectancy may be decreased for diabetic patients with a BMI over 62 kg/m2 after metabolic/bariatric surgery.
I would ask you to provide us all with an additional outcome, which should be available from your dataset. If you exclude all operative, perioperative, and other surgery-related postoperative deaths—in essence totally censor the operative procedure complications from your calculations—what would be the life expectancy prediction for type 2 diabetic patients with a BMI over 62 kg/m2? This implies use of a Poisson Model rather than a Markov Model for your evaluation.
If your answer to the question I have posed is that without the strictly operative effects, the benefits of metabolic/bariatric surgery are positive, rather than negative, with respect to life expectancy, the clinical impact would vary widely. Based on your article, a surgeon during a preoperative consultation would need to say to a type 2 diabetic patient with a BMI over 62 kg/m2 that statistically surgery will decrease the patient's life expectancy. It may, however, be more precise to state to the same patient that metabolic/bariatric surgery will increase your life expectancy; however, at your weight the risk of surgery per se may outweigh this benefit. It is then up to the patient to elect to take the risk or not. Further, it is the responsibility of all metabolic/bariatric surgeons to continue to decrease the risk of metabolic/bariatric operations, particularly in type 2 diabetics with a BMI over 62 kg/m2.