Bariatric Surgery or Medical Management? The Informed Decision
Prospective randomized studies to evaluate the important question of whether medical or surgical management is optimal for treatment of type 2 diabetes in moderately obese patients are now warranted. Trials should aim to identify characteristics of patients who do well and have improved outcomes compared with those who do not so that therapeutic recommendations can be individualized when possible. Trials must be designed to optimize the quality and applicability of the information generated, and there are multiple important methodological issues. Foremost, is the type of surgical procedures to be considered and whether one or more procedures would be compared with standard care or an intensive diabetes and weight management program? If multiple procedures were to be considered, patients may be unwilling to relegate the choice of procedure to a randomized process, and this could represent a significant impediment to subject accrual and study feasibility or generalization of findings. Patient preference toward a specific procedure is strong; in a survey of 2,046 patients in our surgical clinic, 46% preferred RYGB, 42% preferred LAGB, and only 12% had no preference (D.L., unpublished data). Patient and provider biases may differ for patients selected from surgical clinics compared with primary care or endocrine practices. To inform the decision on the relative benefit of surgery to medical care, it is essential to optimize the medical diabetes and weight management for appropriate comparison, rather then compare with standard of care, where many patients may not meet combined glycemic, blood pressure, and lipid goals.
Many deem it most important to study patients with type 2 diabetes who are not currently approved for bariatric procedures, that is, those with a BMI <35 kg/m2. In further consideration of patient selection, excluding patients with very poor glycemic control may be prudent to avoid excess perioperative risks. Conversely, including only patients with poor glycemic control or requiring patients to have inadequately achieved weight loss or glycemic improvement after a period of medical management (typically a 6-month period is currently necessary for many health insurance providers) could bias study results against the medical intervention, because the study would then specifically be selecting those who have been unable to achieve optimal control with nonsurgical treatments. In addition, requiring patients to have higher glycohemoglobin concentrations may select against those with more recent onset of disease who may benefit most by long-standing disease resolution. In consideration of current medical treatment for diabetes, some data suggest patients using insulin may not achieve the same degree of resolution of diabetes after surgical procedures, possibly because insulin use is more prevalent in patients with more long-standing or advanced disease. However, insulin is now frequently used as a second or early pharmacologic intervention because of the clear success in improving glycemia, making it difficult to justify exclusion of insulin-treated patients. Stratification for some of these important covariates may be necessary to apply future study findings to specific patient populations.
Finally, the outcome measures relevant to clinical trials designed to compare the efficacy of surgical and medical management of type 2 diabetes will undoubtedly include achievement of glycemic targets, such as fasting and postprandial blood glucose levels, glycohemoglobin concentrations, continued use of diabetes medications, weight loss, or a combination of these variables. Although defining improvement in glycemic control may be straightforward, defining "cure" of the disease has proven controversial; "remission" is likely a more accurate term. In 2009, a consensus group defined remission of diabetes as achievement of glycemia below the diabetic range in the absence of active pharmacologic therapy or ongoing procedures (e.g., repeated gastric band adjustments or replacements of endoluminal devices). Partial remission was defined as hyperglycemia below the diabetic range (HbA1c <6.5%, fasting glucose 100–125 mg/dL [5.6–6.9 mmol/L]) for at least 1 year; complete remission was defined as a return to normoglycemia (normal HbA1c and fasting glucose <100 mg/dL [5.6 mmol/L]) for at least 1 year; and prolonged remission was defined as complete remission for at least 5 years.
Although improved glycemia is recognized to be an important outcome in patients with diabetes, diabetes is characterized by high rates of microvascular and macrovascular complications; thus, well-designed long-term studies will be needed to determine the effect of each management strategy on the risk of such complications. Following surrogate end points, such as albuminuria, lipid profiles, hypertension, markers of inflammation, and other cardiovascular risk factors, in studies of shorter duration may be useful until longer-term data become available. Longer-term studies should also help clarify the postoperative health risks that may arise over time, such as changes in micronutrients, bone mineral density and fracture risk, the risk of postoperative hypoglycemia, and others.
Diabetes Care. 2011;34(3):763-770. © 2011 American Diabetes Association, Inc.
Cite this: The Great Debate: Medicine or Surgery - Medscape - Mar 01, 2011.