By Harvard Medical International
Surgeons may focus on the gut, but it's also important to consider the brain.
Surgeons may focus on the gut, but it's also important to consider the brain.
Bariatric surgery, which enables people who are severely obese to lose significant amounts of weight, is becoming increasingly popular in the United States.
Bariatric surgery is complicated and involves substantial risks, and recovery can be challenging.
In the year 2000, about 36,700 Americans underwent some type of bariatric surgical procedure; by 2007, more than five times as many - about 205,000 people - had undergone such procedures.
Bariatric surgery is popular because it is the most effective weight-loss option for people whose obesity poses a major health problem. It also alleviates life-threatening complications of obesity, such as diabetes, high blood pressure, and high cholesterol.
But the surgery itself is complicated and involves substantial risks, and recovery can be challenging, requiring a lifelong commitment to behavioural change. It's therefore important that patients considering such surgery be prepared mentally as well as physically.
For this reason, a 1991 consensus panel convened by the National Institutes of Health, which developed criteria for bariatric surgery that are still widely followed, encouraged a multidisciplinary approach both to assess patients and to help them through recovery.
The experts recommended that patients be evaluated by a team that includes medical, surgical, nutritional, and psychiatric experts.
However, the panel did not specify what type of psychological assessments to perform. And no national guidelines on this aspect of the procedure have yet become available.
Clinicians have grown more experienced with bariatric surgery and its physical risks and benefits. The psychological aspects of bariatric surgery are less well understood. Yet about 25% of patients who have undergone bariatric surgery say they are being treated by a mental health professional at the time of surgery, while 12% to 38% say they use psychiatric medications.
Bariatric surgery basics
According to the 1991 consensus criteria, bariatric surgery is an option for people who are severely obese, defined as having a body mass index (BMI) of 40 or more (or 35 or more if other high-risk health problems such as diabetes or heart disease are present). At least 5% of Americans meet these criteria.
Various types of bariatric surgery exist, but all aim to reduce caloric intake. Restrictive operations, such as gastric stapling (gastroplasty) or adjustable gastric banding, reduce the size of the stomach and slow the rate at which it empties.
The Roux-en-Y gastric bypass procedure combines stomach restriction with modification of the intestine, in order to reduce absorption of nutrients during digestion.
Studies indicate that bariatric surgery is more effective than medical management for achieving weight loss. Behaviour modification programs and weight-loss medications usually result in patients initially losing 8% to 10% of their original weight, but they often regain weight after they stop treatment.
In contrast, bariatric surgery usually results in patients losing 20% to 30% of their total weight, depending on the procedure used, within the first two years.
And the results hold up over time.
The Swedish Obese Subjects study, which followed the outcomes of more than 2,000 people for up to 15 years after bariatric surgery, found that they had regained some weight, but remained 13% to 27% under their pre-surgical body weight, depending on the procedure used, while obese controls who received conventional weight-loss treatment remained within 2% of their original body weight.
But bariatric surgery does not work for everyone. One in five patients who undergo bariatric surgery does not lose the expected amount of weight; many others regain weight after the first few years.
Other benefits and risks
Bariatric surgery can result in important health benefits. Diabetes resolves or improves in 86% of patients; high cholesterol improves in 70% or more; hypertension resolves in 62%.
Probably because of these effects, a study that examined the long-term outcomes of almost 10,000 patients who had undergone gastric bypass surgery found overall mortality was reduced in comparison with a matched control group of severely obese who had not undergone surgery.
But bariatric surgery also involves serious risks.
Gastric bypass, for example, may result in deficiencies of essential nutrients such as iron, calcium, and folic acid. Several large studies have reported mortality rates ranging from 0.1% to 2%, depending on the bariatric procedure used, and a study in Pennsylvania reported even higher rates. As discussed below, risk of suicide may also increase after bariatric surgery.
Although bariatric surgery is generally associated with improved mental health, post-surgical psychological and behavioural changes are less predictable than physical changes.
Depression and mood disorders
Mood disorders affect many people who are eligible for bariatric surgery.
About half of bariatric surgery candidates say they have experienced depression or some other mood disorder at some point in their lives. And one epidemiologic study found that people with a BMI greater than 40 were five times as likely as someone of average weight to have had major depression in the previous year. Anxiety disorders have been diagnosed in as many as 48% of candidates for bariatric surgery.
Weight loss following bariatric surgery generally improves mood, at least initially.
The Swedish study found reductions in depression and anxiety one year after surgery. For example, depression scores fell 40% in patients who underwent bariatric surgery, compared with 10% in the group of control patients. The investigators noted similar improvements in anxiety scores.
However, when patients were assessed again at two and four years after bariatric surgery, their depression and anxiety scores had increased slightly from the levels recorded during the first year following surgery.
It is not clear how much of this is due to dissatisfaction with the amount or rate of weight loss (which may plateau with time or not be as significant as the person hoped).
Some research has found higher-than-expected rates of suicide among bariatric surgery patients.
For example, a team at the University of Pittsburgh, which analyzed the results of 16,683 bariatric surgery operations performed in Pennsylvania between 1995 and 2004, found that 16 people had committed suicide within five years of the surgery - significantly greater than what the researchers expected based on age-adjusted U.S. statistics for the general population.
Studies indicate that bariatric surgery is more effective than medical management for achieving weight loss.
And this could be a conservative number: another 14 deaths occurred after drug overdoses, and the researchers think some of these were likely suicides.
Whether any additional risk of suicide is due to a history of depression, the psychological challenges of severe obesity, or perhaps disappointment with the results of bariatric surgery remains unclear.
However, the risk further emphasises the importance of providing mental health care to patients both before and long after bariatric surgery.
In the Pennsylvania study, for example, most suicides occurred a year or more after surgery.
About 10% to 25% of people considering bariatric surgery have been diagnosed with binge eating disorder, and about 5% to 20% have night eating syndrome.
Of course, severe obesity most likely develops because of some underlying disordered eating pattern, diagnosed or not. So it's wise to include a plan to address eating behaviours both before surgery and during recovery.
Otherwise, eating and digestive problems may complicate recovery.
For example, studies have found that a condition known as gastric dumping occurs in 50% to 70% of patients who have had gastric bypass surgery. Its symptoms include facial flushing, palpitations, lightheadedness, fatigue, and diarrhoea, often triggered by the consumption of foods that contain a lot of sugar.
This occurs because the digestive tract has been altered in a way that affects the release of certain hormones and digestive enzymes.
Other research indicates that about half of patients who undergo restrictive bariatric procedures will experience nausea and vomiting, usually because they eat too much, too rapidly. Several studies indicate that both dumping syndrome and postoperative nausea may be prompted at least in part by binge eating.
Obesity impairs overall quality of life. And while less research has been done in this area, it appears that bariatric surgery improves quality of life for patients - although it may take some time for them to notice the changes.
For example, the Swedish study found that people who underwent bariatric surgery were 35% more likely than a control group to call in sick during the first year after bariatric surgery, probably because they were recovering from the operation. However, by the second and third years after surgery, they had significantly fewer sick days than the control group.
A number of studies have found that people who undergo bariatric surgery feel better about how they look afterward. One team found that 70% of patients had severe body image problems before surgery; after surgery and weight loss, only 4% did.
And although only a few studies have examined the impact of bariatric surgery on relationships and marriage, they indicate that the post-surgical outcome largely depends on the quality of the pre-surgical relationship. But in general, relationships are more likely to improve than deteriorate after bariatric surgery.
Official guidelines aren't available, but the American Society for Metabolic and Bariatric Surgery suggests that clinicians assess the following areas in patients considering bariatric surgery:
• Behavioural status
- Past weight-loss attempts
- Eating patterns
- Physical activity levels
- Substance use
- Impulsive or compulsive behaviour
- Criminal or legal history
• Cognitive and emotional status
- Cognitive functioning
- Awareness of risks and benefits of surgery
- Coping skills
• Current situation
- Social support
- Motivation and expectations
Questions for the future
As researchers continue to follow people who have had bariatric surgery for longer periods of time, it is likely that other benefits and risks will emerge. One highly controversial issue - as yet unproven - is that bariatric surgery may cause some people to lose weight but then "transfer" their food addiction to some other harmful addiction.
Some types of bariatric surgery do increase the rate at which alcohol is absorbed, so that people become intoxicated on smaller amounts of alcohol than they did before the surgery. This may increase the risk of dependence in people who are vulnerable to becoming addicted, underscoring the need for pre- and post-surgical substance abuse assessments.
Although much remains unknown, bariatric surgery provides the only viable weight-loss option for some people who have become severely obese. As the statistics show, an increasing number of people are willing to accept the risks and side effects for the benefits of better health and quality of life.
This article is provided courtesy of Harvard Medical International. © 2007 President and Fellows of Harvard College.
For more information
DeMaria EJ. "Bariatric Surgery for Morbid Obesity," New England Journal of Medicine (May 24, 2007): Vol. 356, No. 21, pp. 2176-83.
Wadden TA, et al. "Psychosocial and Behavioral Status of Patients Undergoing Bariatric Surgery: What to Expect Before and After Surgery," Medical Clinics of North America (May 2007): Vol. 91, No. 3, pp. 451-69.