Optimal Management for Obese Patients with Type 2 Diabetes: Surgery vs Medical Therapy
Optimal Management for Obese Patients with Type 2 Diabetes: Surgery vs Medical Therapy
Abstract & Commentary
By Jeff Unger, MD
Director, Metabolic Studies, Catalina Research Institute, Chino, CA
Dr. Unger reports no financial relationships relevant to this field of study.
Synopsis: At 2 years, none of the patients maintained on medical therapy had entered into a state of diabetes remission, whereas 75% of the gastric bypass and 95% of the biliopancreatic diversion patients had become diabetes free.
Source: Mingrone G, et al. Bariatric surgery versus conventional medical therapy for type 2 diabetes. N Engl J Med 2012;366:1577-1585.
AT BASELINE, THE MEDIAN A1C OF THE MEDICALLY MANAGED PATIENTS was 8.51% (± 1.24), whereas the surgical cohort A1C averaged 8.72% (± 1.55). Initial body mass index (BMI) was 45.62 kg/m2 (± 6.24) vs 44.99 kg/m2 (± 6.47) for the medical vs the surgical cohort, respectively. All patients received periodic evaluations from a diabetologist, RD, and a nurse throughout the 2-year study period. Oral hypoglycemic agents and insulin doses were optimized among the intensive medically managed patients with the ultimate glycemic target being an A1C < 7%. Programs for diet and lifestyle modifications, including reduced fat intake and increased physical activity (≥ 30 minutes of brisk walking daily and intermittent moderate-intensity aerobic activity), were also encouraged.
The Roux-en-Y gastric bypass procedure is named after the surgeon who first described the operation in 1993 and the “Y” shape produced by the redirected intestines as food is rerouted around the stomach. The surgeon creates a walnut-sized pouch (1-2 tablespoons) on the proximal area of the stomach and “bypasses” the remaining stomach by attaching a section of the small bowel to the pouch. Although the stomach does not receive any nutrients, gastric enzymes continue to be produced. The gastric pouch is anastomosed to a Roux-en-Y proximal jejunal segment, bypassing the remaining stomach, duodenum, and a small portion of jejunum. The standard Roux (alimentary) limb length is about 50 to 100 cm, and the biliopancreatic limb is 15 to 50 cm. The Roux limb allows the gastric content to mix with nutrients entering from the gastric pouch and bypassing the stomach. Patients experience very rapid fullness with this procedure and significant weight loss. The gallbladder is typically removed during this procedure, as patients who experience rapid weight loss have a higher incidence of cholelithiasis. The procedure may be performed laparoscopically.
The bilio-pancreatic diversion (BPD) amputates 60% of distal stomach with stapled closure of the duodenal stump. This leaves a residual volume of 300 mL. The small bowel is transected and its distal end anastomosed to the remaining stomach pouch. The proximal end of the ileum comprising the remaining small bowel carrying the bilio-pancreatic juice, yet excluding bowel involved in food transit, is anastomised in an end-to-side manner to the bowel 50 cm proximal to the ileo-caecal valve. With minimal gastric capacity, patients quickly develop satiety and weight loss ensues. BPD is an open procedure.
Two years following randomization, diabetes remission had occurred in none of the patients receiving medical therapy as compared with 75% of those who underwent gastric bypass and 95% of patients who had BPD (P < 0.001 for both comparisons). The average time to normalization for fasting glucose and A1C among the surgical patients was 10 months for gastric bypass and 4 months for BPD. After 2 years, the average percent of weight loss from baseline in the medical cohort was 4.74 (± 6.37%). Gastric bypass patients lost on average 33.31 % from baseline (± 7.88%) vs BPD patients 33.82% (± 10.17%).
Two patients receiving metformin in the medical cohort had persistent diarrhea during the study. A BPD patient developed an incisional hernia requiring repair 9 months after undergoing their initial procedure. One gastric bypass patient required surgical intervention for an intestinal obstruction 6 months post procedure.
The authors conclude that surgical intervention is more effective than conventional medical therapy in controlling hyperglycemia in severely obese patients with type 2 diabetes.
Commentary
The fact that surgery overpowers metformin et al as a means to cure type 2 diabetes should come as no surprise to those of us who study the history of diabetes. After all, insulin was discovered in 1922 by of all people, a general surgeon (Fred Banting) and his medical student (Charles Best). Interestingly, Dr. Banting was not permitted to administer the first insulin injection to a human subject (Leonard Thompson) on December 2, 1922, at Toronto General Hospital. Instead, the honor went to Ed Jeffrey, an intern at the facility. The dose of insulin was calculated by Banting based on the estimated glucose-lowering effect that a similar dose would have on the weight of a dog.
Now 90 years later, those of us who manage patients with diabetes are still reaching out to our surgical associates for assistance in treating this chronic, progressive disease state. The primary risk factor for type 2 diabetes is obesity, and 90% of all patients with diabetes are overweight or obese. The relative risk of diabetes increases nearly 42-fold in men as the BMI increases from 23 to 35 kg/m2 and approximately 93-fold in women as BMI increases from 22 to 35 kg/m2. Long-term maintenance of weight loss is difficult for anyone, especially those with diabetes.
Bariatric surgery improves endogenous insulin secretion and peripheral insulin sensitivity two-to-three fold before any substantial weight loss is observed. A study by Keidar has suggested that weight-loss surgery reduces diabetes-related mortality by 90% over conventional care.2 As many as 14,300 lives can be saved in the United States over 5 years through bariatric surgery, yet fewer than 1% of eligible patients are referred to bariatric surgeons for consultation.
This study, as well as one published by Schauer et al,3 suggest that bariatric surgery should be considered sooner rather than later in obese patients with diabetes. Within 1-2 years following surgical intervention, more patients are able to attain remission of their diabetes and normalize their A1Cs than if prescribed intensive medical therapies. Surgeons are no doubt proud of their contributions to the field of diabetes management, knowing that use of their scalpel or laparoscope can normalize hyperglycemia in highly insulin-resistant patients within hours of their discharge from the recovery room.
This week, a newly diagnosed patient with diabetes and a BMI presented to my office. Weighing in at 425 pounds and carrying a BMI of 67 kg/m2, do you really think that a trial of metformin and jumping rope for 30 minutes per day would result in remission of his diabetes? His baseline A1C was 10.6%. After explaining the pathogenesis of diabetes to this patient, he was immediately referred to our local bariatric surgeon for consultation. I told the patient that within the next 4 months his weight should be down by 40 pounds and his diabetes should be in remission. Have you ever had a patient thank you for placing him on insulin?
In summary, bariatric surgery appears to be the most effective long-term intervention for inducing remission as well as minimizing morbidity and mortality associated with severe clinical obesity and type 2 diabetes.
References
1. Mechanick JI, et al. Endocr Pract 2008;14(Suppl 1):1-83.
2. Keidar A. Diabetes Care 2011;34(Suppl 2):S361-S366.
3. Schauer PR, et al. N Engl J Med 2012;366:1567-1576.
4. Bult MJ, et al. Eur J Endocrinol 2008;158:135-145.
At 2 years, none of the patients maintained on medical therapy had entered into a state of diabetes remission, whereas 75% of the gastric bypass and 95% of the biliopancreatic diversion patients had become diabetes free.Subscribe Now for Access
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