Saturday, April 1, 2023
processing....
At this year's meeting of the American College of Gastroenterology, a symposium on the management of obesity was held. The slant was toward what gastroenterologists can do, but, clearly, the talks have an impact on the interdisciplinary role needed for clinicians to deal with this growing American problem. The talks were classified into 3 general areas: medical management,[1] surgical management,[2] and management of bariatric surgery complications.[3]
Almost 65% of Americans are either overweight or obese.[4] After smoking, obesity is the second most preventable cause of death in our country.[5] Obesity is also rampant in our children, who comprise the fastest-growing group becoming overweight or obese.[6] There are many reasons to reduce this epidemic. Among them are that obese individuals have a higher rate of cancer and that the costs to care for obese patients are about 38% higher than the costs of caring for nonobese patients.[7,8]
Many GI problems exist in the obese population that need care, including gallbladder disease, pancreatitis, reflux, and liver disease. Of note is that obesity-related liver disease (nonalcoholic fatty liver disease) is likely to become a major indication for liver transplantation in the very near future. Also, for those individuals who undergo surgical treatment of obesity, there will be a need for physicians to provide postoperative care.
Many individuals would like to blame their genetic makeup for their weight problems; however, only 40% of the tendency to be overweight comes from what is inherited. It appears that the environment has a major input. Higher caloric intake with less energy expended is a formula for weight gain.[9]
The first thing that patients and physicians alike must understand is that obesity is a chronic problem. Unfortunately, we have not been as successful in treating this problem as we have in treating hypertension or hyperlipidemia. Office or hospital evaluations should begin with the determination of the body mass index (BMI), which is usually a good indicator of excess body fat.[10] Note that individuals with excess muscle mass may have a BMI suggesting obesity. Also, some people with BMI in the normal range may have reduced muscle mass and excess fat.
Table 1 shows the derivation of the BMI. However, it is much easier to use tables, wall charts, or calculations done on your personal digital assistants.
| BMI = Weight (kg)/height2 (m2) Overweight: BMI = 25.0-29.9 Obese: BMI ≥30 |
One reason why it is difficult to treat obesity is that people set unrealistic goals. For most individuals who are not contemplating surgery, an initial weight-loss goal should be between 5% and 10% of the starting weight.[11] Clearly, for most people this could represent a very small amount; however, this strategy has the advantage of not only being achievable by most people, but also represents a weight loss associated with an amelioration of many medical problems.
At any one time, about 45% of US women and 30% of US men are trying to lose weight.[12] The management of obesity may consist of the following: diet, exercise, behavior modification, pharmacologic interventions, and/or surgery. The mainstay of any weight-loss regimen is a reduced calorie intake, or weight-loss diet. There have been many controversies over the years about which "diet" is best. Unfortunately, the jury is still out.[13,14] Low carbohydrates compared with high carbohydrates or low-fat diets are now being more rigorously investigated, but the bottom line is the same -- reduce the caloric intake to help lose weight. Referring patients to a registered dietitian can help direct them toward a better dietary plan.
Much emphasis is placed on exercise, and deservedly so -- it is an important component of an approach to losing weight. For most individuals, walking is fine. Start slow, and gradually add time and increase the speed. If orthopaedic issues are a problem, then swimming or other activities may be useful. It has been shown that adherence to an exercise program can predict the long-term maintenance of a person's weight loss.[15,16] Availability of an exercise physiologist or personal trainer may be beneficial.
Behavior modification can be helpful in teaching patients why they turn to food for comfort or in teaching strategies for changing eating behavior. By itself, it may have a very small effect, but as part of a weight-loss program, behavior modification can have a more additive effect.
Unlike hypertension, diabetes, or hyperlipidemia, for which there is a plethora of medications, the medical treatment of obesity is limited to very few specific medications. Table 2 lists the current medications that are FDA-approved for the treatment of obesity. Of these medications, only 2, sibutramine and orlistat, are FDA-approved for up to 2 years of use. The other medications that are effective -- phentermine, phendimetrazine, and diethylpropion -- are labeled for short-term use, meaning up to 12 weeks. This equates to a short-term fix for a long-term problem. Side effects for all of the drugs listed in Table 2 except orlistat commonly include elevation of blood pressure, tachycardia, central nervous system overstimulation, dry mouth, and, rarely, memory loss.[17] Their use should be avoided in patients with advanced arteriosclerosis and uncontrolled hypertension, as myocardial infarctions and strokes can occur. Also, avoid these medications within 14 days of taking monoamine oxidase (MAO) inhibitor medications. Phentermines have been used very successfully in helping to reduce weight, but their long-term use must be readdressed.
| DEA Schedule | Generic Name | Sample Trade Name(s) |
|---|---|---|
| NS | Various over the counter | Various - currently with and without ephedra |
| CIV CIV |
Phentermines: Hydrochloride Resin |
Adipex-P
a, others Ionamin b |
| CIII | Phendimetrazine tartrate | Prelu-2c, Bontril d |
| CIV | Diethyproprion hydrochloride | Tenuate e |
| CIV | Sibutramine | Meridia f |
| NS | Orlistat | Xenical g |
NS = Not scheduled
aGate Pharmaceuticals, North Wales, Pennsylvania
bCelltech Pharmaceuticals, Rochester, New York
cRoxane Laboratories, Columbus, Ohio
dAmarin Pharmaceuticals, Mill Valley, California
eAventis Pharmaceuticals, Bridgewater, New Jersey
fAbbott Laboratories, North Chicago, Ilinois
gRoche Laboratories, Nutley, New Jersey
Orlistat is unique in that it is a lipase inhibitor and will block about one third of ingested fat. Its mode of action thereby leads to GI side effects such as oily discharge or loose stools. These can be minimized by the use of psyllium, (see footnote).[18]
There are many other medications being evaluated at the present time, but their approval for common use may be years away. Surgical options remain very effective methods of weight loss and must be put into the proper perspective. However, our country needs to consider that the prevention of obesity may be its best treatment.[19]
If weight loss is beneficial to the treatment of obesity, then surgical intervention can deliver results. Why are people interested in surgery as an option? There are many reasons why the public is interested, such as the availability of a laparoscopic approach, published outcomes data, access to Internet information, positive family and peer experiences with surgery, positive celebrity experiences with surgery, and the media attention to surgical choices and their risks.
Foremost, there are successful data. A National Institutes of Health (NIH) consensus conference was held in 1990 and concluded that bariatric surgery was appropriate for individuals with a BMI ≥ 40 or a BMI ≥ 35 if there are significant comorbidities.[20] The goals of surgical treatment are to induce and maintain significant loss of excess weight through a safe operation, to ameliorate or resolve the chronic health conditions associated with obesity, and to improve the quality of life. Pathophysiologically, all bariatric surgical procedures create either intestinal malabsorption or gastric restriction, or a combination of both. Patients should be well-informed, highly motivated individuals who have acceptable surgical-risk profiles. Selection of patients should occur through a multidisciplinary approach that includes medical, surgical, psychiatric, and nutritional expertise. Patients should choose an experienced surgeon who has multidisciplinary support and who is capable of lifelong medical surveillance.[21]
The preoperative patient evaluation should include a thorough assessment of the individual patient with a careful history, comprehensive physical exam, and detailed lab testing, with additional emphasis on informed consent and patient education. The goal is to evaluate all medical comorbidities, but these do not disqualify most patients. Common obesity-related comorbid conditions that are often diagnosed by the surgeon include the following: obstructive sleep apnea syndrome, coronary artery occlusive disease, deep venous thrombosis and/or pulmonary thromboembolism, history of blood-clotting abnormalities, and neurologic conditions such as pseudotumor cerebri. The usual age range for this surgery has traditionally been 18-50 years of age, but there are now emerging data for teenagers aged 12-17 and older patients aged 50-75 years.[21,22]
Table 3 lists the currently performed surgical procedures for obesity. The surgical focus now is on the ability to operate laparoscopically because of decreased disability and morbidity. The 2 primary procedures that are being performed are the laparoscopic adjustable gastric banding (Lap-Band) and the laparoscopic proximal gastric bypass (also called the Roux-en-Y proximal gastric bypass). There are no prospective randomized, controlled trials of the Lap-Band procedure, but rather only data from prospective database reviews. [23-26] The Lap-Band procedure has also been criticized for a high failure rate and poor results in African-Americans.[26] The Lap-Band is a restrictive procedure and can be defeated by eating high-calorie sweets, and there are surgical learning-curve issues regarding band placement and management. The current recommendation is that the Lap-Band needs more study before universal use in the United States.
|
Restrictive procedures
Gastroplasty (vertical banded) Lap-Band |
|
Malabsorptive procedures
Distal bypass Biliopancreatic diversion Duodenal switch Combination restriction/malabsorption Roux-en-Y proximal gastric bypass |
Presently, the most effective and commonly performed bariatric surgery in the United States is the Roux-en-Y proximal gastric bypass (GPB), which is a combination restriction/malabsorption procedure. This was shown by Sugerman and colleagues to be effective because sweets eaters could defeat the restrictive procedures by drinking high-calorie drinks, but with the GPB this would induce a dumping syndrome (manifested by nausea, lightheadedness, flushing, and diarrhea) and help condition patients not to abuse these types of foods.[27] This surgery is now performed laparoscopically, and the data are very good in one series of 281 consecutive bypass operations.[28] Patients leave the hospital within 3-5 days and the operation carries a mortality rate of 0.8% (Demaria EJ, unpublished data). At 1 year, there was a weight loss of 70% ± 15% of excess body weight. There was also a significant improvement in the comorbidities with a resolution of type 2 diabetes requiring medication (93%), gastroesophageal reflux disease (GERD) (95%), urinary incontinence (88%), orthopedic problems (76%), and hypertension (52%). Conclusions from unpublished data from this series suggest that the safety profile is acceptable, with a decreased number of wound complications.
With the current increase in the number of bariatric surgeries nationally, it will be important to continue to collect data and to refine the current surgical techniques . In this way, bariatric surgery will remain a beneficial option for the obese patient.
As might be expected, performing surgery in obese patients is fraught with a number of potential complications. Some of these are due to the excess weight while others may be the result of a particular operation. General complications related to surgery in the obese population include the following: deep venous thrombosis (DVT) and pulmonary embolus (PE), atelectasis and other respiratory complications, anastomotic or staple-line leaks, and incisional hernias. The most common cause of unexpected death in this population is PE -- the incidence of post-op PE is about 1% to 2%, but nearly one third will die.[29] The overall incidence of DVT/PE is reported to be 2%.
Anastomotic or staple-line leaks are estimated to occur in approximately 2% to 5% of laparoscopic procedures, compared with 1% to 2% of open procedures. However, the rate of this complication improves further (to approximately 1%) with increasing experience of the surgeon and with other surgical refinements.
Incisional hernias are the most common late complication after open gastric bypass, with an incidence ranging from 10% to 20%. This complication has been dramatically reduced by the laparoscopic technique to about 2% (Demaria EJ, unpublished data).
A complication from rapid weight loss induced by either medical or surgical weight loss is that of cholelithiasis. Patients who have gallstones at the time of surgery often have a cholecystectomy. Otherwise, the use of ursodiol therapy (300 mg twice daily) has been found to be very effective in reducing the incidence of cholelithiasis.[29] If symptomatic gallbladder disease occurs postoperatively, then laparoscopic cholecystectomy is appropriate.
Complications that are specific to restrictive procedures are listed in Table 4. Acute gastric distention is an uncommon complication that can manifest as massive gastric distention in the bypassed segment. Edema or obstruction at the enteroenterostomy is the etiology. Internal hernias occur in less than 3% of patients and can cause nausea and vomiting or intermittent abdominal pain. This may require surgical exploration.[31]
| Acute gastric distention Bowel obstruction Internal hernias Stomal ulceration Stomal stenosis Staple-line disruption Wound infections Nutritional complications Metabolic bone disease Late gastrointestinal hemorrhage from the excluded stomach/duodenum |
Stomal ulcerations occur in up to 15% of undivided gastric bypasses and at a somewhat lower rate in the divided bypasses. The etiology may be from acid peptic disease, ischemia, or tension at the anastomosis, or even from the use of nonsteroidal medications. The stoma is the first connection between the small (50 mL) gastric pouch and the loop of small intestine that is brought up to attach and bypass a portion of the small intestine. Narrowings of the pouch postoperatively can lead to nausea/vomiting and pain -- in the most severe narrowings, patients can become dehydrated and require intravenous fluids. The optimal stomal diameter is 1 cm; stomas larger than that can allow more food to pass and can be associated with less weight loss. The stomal ulcerations can be part of the process in causing a narrowing. Stomal stenosis can occur in up to 12% of patients and, if symptoms develop, may require endoscopic dilatation or, very rarely, reoperation. Staple-line disruption can occur in vertical-banded gastroplasty and in the undivided gastric bypass procedure. Symptoms can be subclinical and decrease the efficacy of the procedure.
Late GI bleeding can occur from the excluded stomach or duodenum. It may be difficult to endoscopically visualize the bleeding site.
Wound infections can be seen in 1% to 3% of procedures and may occur at a lower rate in those performed laparoscopically. Bowel obstruction can occur, as after any other abdominal procedure.
Metabolic bone disease and nutritional deficiencies can occur after restrictive procedures. While protein-calorie malnutrition is uncommon, iron, folate, and vitamin B12 deficiencies and calcium malabsorption may occur.
Table 5 lists the complications that are specific to malabsorptive procedures. Similar operative complications may occur, but due to the nature of these procedures, the number and severity of the nutritional complications can be higher and greater, respectively. However, these procedures may be performed in patients with very high BMI, and the severely altered anatomy and resulting malabsorption are what help to effect the weight loss.
|
Now is the time for clinicians of all specialties to help fight this obesity epidemic. We can either be part of the problem or help with the solution.
