The Swedish Obese Subjects study is a fabulous example of how very-useful practical knowledge can come out of a well-conducted cohort study. Not everything has to be a prospective randomized controlled trial! This study has produced a number of landmark papers which provide convincing evidence that:
1. Bariatric surgery offers survival benefit over the long term for the morbidly obese, despite the up-front mortality risk from the surgery itself.
2. Bariatric surgery reduces cardiovascular and cancer deaths
3. Bariatric surgery is durable: most patients do not regain the weight back
4. Not all bariatric procedures are the same. Some work better than others.
5. Diets, behavioral modification, and “professional” weight loss coaching doesn’t really work for the morbidly obese in the long haul.
6. And now….bariatric surgery prevents onset of diabetes!
The strength of the Swedish Obese Subjects trial is in the follow-up. Since Sweden has a nationalized health care system, follow-up was completed on >95% of the initial cohort. Such a trial could never be conducted in the United States….our people change jobs, towns, or insurances just way too often!
And there is just one more thing you should know about the Swedish Obese Subjects trial: the vast majority of the surgery cohort underwent vertical banded gastroplasty (VBG). What’s that, you ask? It was a first-generation bariatric operation that has been abandoned worldwide in favor of better (i.e. more effective) operations, such as gastric bypass and sleeve gastrectomy. So if this trial were repeated in 2012, we would expect even better results in the surgical arm with fewer complications.
So where does that leave us? For any patient with BMI > 40 (or BMI >35 with metabolic disease), you should really get them thinking about surgery as an option. It’s not just about weight, and certainly has nothing to do with cosmetic appearance. It’s about getting serious about treating metabolic disease: diabetes, hypertension, sleep apnea, hypercholesterolemia, PCOS, and others. It’s about making sure that those diseases never develop in the first place. It’s about reducing overall cancer risk, stroke risk, and heart attack risk. And it’s about improving overall quality and quantity of life.
So why, then, with such powerful clinical evidence, do less than 1% of adults who would benefit from bariatric surgery actually get it? That, my friend, is complicated, and probably worth another blog in its own right!
Jonathan Carter, MD