Laurence Kennedy MD, FRCP
Department of Endocrinology, Diabetes and Metabolism
Cleveland Clinic
Cleveland OH
It is universally accepted that weight loss achieved by calorie reduction (diet) plus increased energy expenditure (exercise) is highly desirable in patients with type 2 diabetes. That these steps can lead to improved glycemic control even without the addition of antihyperglycemic drugs has been shown;1,2 the problem is one of sustainability beyond a year or two. This patient, with a BMI of 36, exemplifies the problem in that he acknowledges that any success achieved previously with a variety of diets has been purely temporary.
A major determinant of the most appropriate treatment option is finding out the patient’s goals and educating him on what the goals realistically should be. Therefore, I would counsel this patient that, among other goals, achieving sustained weight reduction should be high on his list. And the truth is, in 2013, that if we do not at least acquaint our obese (and perhaps also simply overweight) patients with the option of bariatric surgery as a legitimate treatment for their type 2 diabetes, then we are selling them short and likely bending to our own prejudices against what may be thought of as a step too far.
So what are the facts?
Over a period of up to 20 years the Swedish Obesity Subjects (SOS) study has demonstrated that, in comparison to people of similar obesity and cardiovascular risk, those who opted for a bariatric procedure had weight loss that was substantial and sustained; decreased cardiovascular morbidity and mortality; and, if they were diabetic at the outset, decreased use of antihyperglycemic and antihypertensive medications, and, in many cases, remission of diabetes in that they could maintain normal HbA1c without antihyperglycemic drugs.3-5 Furthermore, their cancer mortality, not just cardiovascular mortality, had decreased.4
It may be argued that the SOS study was not randomized and that only a minority of the participants was diabetic to start with. True, but it should be pointed out that several prospective randomized studies in patients with type 2 diabetes have confirmed that, in the short term at least, bariatric surgery is more successful than medical management in achieving normal HbA1c without the need for antihyperglycemic drugs, and decreased intensity, and therefore cost, of drug use (both antihyperglycemic and antihypertensive) in those who still need medication.6-8
In the SOS study the majority of patients had some sort of banding procedure rather than the more invasive forms of bariatric surgery – Roux-en-Y gastric bypass (RYGB) or pancreaticobiliary bypass. The former can be thought of as “restrictive” of calorie intake, the latter combining restriction with elements of malabsorption and altered nutrient dynamics. In the USA, RYGB has been the more frequently favored procedure. Improvements in glycemic control occur more rapidly with RYGB than with simpler restrictive procedures like banding or sleeve gastrectomy, suggesting there is more at play than simple decreased caloric intake. Enhancement of the incretin system, through more rapid delivery of nutrients to the more distal part of the small intestine, is the most favored and researched explanation (hindgut hypothesis), though bypass of the upper part of the small intestine may itself have an effect (foregut hypothesis).9,10
Putting adverse effects in perspective
Having discussed this topic with many patients and physicians, I have an impression that many people— physicians as well as patients—assume bariatric surgery will likely lead to severe and unpleasant, long-term, adverse effects. In my opinion it is very important to acknowledge the potential shortcomings, just as we do with medical therapy, but we should look to the published literature rather than our own possible preconceived prejudices to inform the advice we give to patients.
Perioperatively the risks of bariatric surgery performed laparoscopically, by an experienced surgeon, are similar in scope and frequency to those of laparoscopic cholecystectomy, with the addition of gastric leakage. In the longer term there can be a number of complications, including nausea, vomiting, dumping syndrome, hypoglycemia, malnutrition and vitamin deficiency, gastric or intestinal ulceration, obstruction, and depression—a daunting list, no doubt, but no more daunting than what a patient will read on the average package insert of most commonly prescribed drugs!
So, just as with the potential adverse effects of drugs we must keep these in perspective, and I would point out that the long term results of the SOS study are very reassuring in this respect, with a risk/benefit ratio heavily in favor of benefit over risk.3-5 However, I cannot overstress the importance of long-term follow up, and it is probably true that too many patients are cast adrift a short time after the “quick fix” of bariatric surgery, with inadequate long-term medical follow-up and monitoring.
What of costs?
There is no doubt that the bariatric surgery option has high initial costs, and medical insurers tend to take a relatively short-term view. But all the evidence suggests that in the longer term, with decreased likelihood of microvascular complications, decreased cardiovascular events, and decreased prescription costs, bariatric surgery will indeed be cost-effective.
Why bariatric surgery makes sense for this patient
Turning to the patient in question, his three months of “lifestyle management” treatment has resulted in a paltry 0.4% reduction in HbA1c, suggesting just what we should have expected from his history—poor compliance with the perceived drudgery of lifelong dieting. This bodes ill for any likely future success in terms of weight especially when the psychological imperative to do well with diet is relieved by the prescription of drugs that will improve his hyperglycemia. So in my opinion he is an ideal candidate for consideration of bariatric surgery. There is the added benefit that he may not need to remain on the antihypertensive and lipid-lowering drugs he currently requires.
But lest it be thought that mine is an ectopic and biased view from an institution with a recognized leaning towards the potential benefits of bariatric surgery for patients with type 2 diabetes, the International Diabetes Federation Taskforce on Epidemiology and Prevention in 2011 endorsed the view that bariatric surgery “is an appropriate treatment for people with type 2 diabetes and obesity (BMI equal to or greater than 35) not achieving recommended treatment targets with medical therapies, especially where there are other obesity-related co-morbidities. Under some circumstances people with a BMI 30-35 should be eligible for surgery.”11 It is surely but a small step to recognize the logic of suggesting bariatric surgery as an initial consideration when current medical therapies have such a high likelihood of falling short.