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Rationale for Surgical Treatment of Obesity

• Section 1. Obesity Overview
  
  • What's Your BMI?
• Section 2. The Problem with Obesity
  • Earlier Death
  • Medical Problems
  • Physical Limitations
  • Social Isolation
• Section 3. The Benefits of Weight Loss
  • Weight Loss Surgery Effects on Health Problems
  • Weight Loss Surgery Effects on Risk of Dying
    
    

Section 1. Obesity Overview [back to top]

Obesity is the most common chronic health problem in the United States. The most recent figures show that 66.3% of all Americans are overweight or obese, 32.2%, are obese, and 4.8% are morbidly obese. For women in the 20 to 59 year age group, 8.0% are morbidly obese.

There are a variety of ways to define different levels of overweight and obesity. The most common and useful method is to use body mass index (BMI), which is simply a number calculated from your weight and height. BMI combines weight and height according to the following formula in the metric system:



Using pounds and inches, the calculation is modified slightly:




What is your BMI? [back to top]
Your BMI is more easily read from a table (see appendix A) or calculated at a BMI calculator (google "BMI calculator"): http://www.nhlbisupport.com/bmi/.

Most clinic offices now calculate BMI as part of their standard evaluation of the vital signs (along with blood pressure, pulse, respiratory rate, and temperature) during clinic visits with your health care provider.

The healthiest BMI is between 20 and 25. Overweight people have a BMI between 25 and 30 and obese individuals have a BMI greater than 30. Severe obesity is defined by a BMI of 35 or greater while morbid obesity is defined by a BMI of 40 or greater. Super morbid obesity includes those patients with BMI of 50 or greater.

Beyond a BMI of 20, increasing health risk for a number of health conditions rises as BMI increases. Higher risk has been observed for high blood pressure, type 2 diabetes, heart disease, stroke, gallbladder problems, joint arthritis, sleep apnea and breathing problems, and some types of cancer (uterine lining, breast, prostate, and colon). Obesity is also associated with complications of pregnancy, menstrual irregularities, excessive hair growth from abnormal hormones, urinary stress incontinence, and psychological disorders (depression).

At least a threefold increased risk is seen for diabetes type 2, gallbladder disease, sleep apnea, insulin resistance, difficulty breathing, high blood pressure, and high cholesterol.

This table outlines the lower limits for overweight, obesity and severe obesity.


If your BMI is greater than 35, it is likely that you are suffering major medical, physical or social problems because of your weight. Some people suffer these problems with a BMI lower than 35, and some people (usually younger) don't seem to have major problems even with a BMI higher than 40. It is typically around a BMI of 35 that major problems due to obesity start to increase in incidence and extent.


Section 2. The Problem with Obesity [back to top]

Earlier Death [back to top]
The risk to your health and life that obesity brings is very slow to evolve and takes a long time to recognize. This process is far more difficult to understand than a more acute process such as a heart attack. An obese person is less likely to focus on the fact that they are less likely to live a long life than someone who isn't obese.

Life insurance companies have known for a long time that more obese people live shorter lives. If you have a higher BMI, then you will be a much higher risk for them to insure and your annual premium will be much higher.

The following graph shows the risk of dying in a large study of women aged 30 to 59 followed for many years. A normal weight person in this group has a risk of dying defined by a relative risk of 1.0. As BMI increases towards the right side of the graph, the risk of dying rises substantially. A woman in this group with BMI of 40 has a 170% higher risk of dying than a normal weight woman in the same group.



As your weight increases, so does the risk. If your BMI is higher than 35, your risk has already increased substantially. The risk of dying can be expected to rise steeply as BMI goes higher than 40.

There have also been studies from the VA Medical Center which have shown that for men in the age range 25-35 with BMI > 40 there is a 12-fold higher risk of dying than for normal weight men in the same age group.

Medical Problems [back to top]
The next major group of problems caused by morbid obesity is medical diseases. There is a long list of illnesses that are either caused by obesity or are made worse by obesity. There are too many for you to focus upon so we will shorten it to the more important and frequent problems.

The risk of diabetes, high blood pressure, and elevated cholesterol are all at least tripled in relative risk. Each of these is a cardiovascular risk factor which contributes to coronary heart disease, stroke, and other blood vessel diseases. These are all increased in morbidly obese patients.

Obstructive sleep apnea, which cases you to stop breathing while sleeping, and severe degenerative joints from excessive wearing out of the weight-bearing joints (hips, knees, and ankles) are also greatly impacted by obesity. In addition, polycystic ovary syndrome, impaired fertility, low back pain, breathlessness, anesthesia risk, and gallbladder disease are also increased in incidence.

Obesity is a chronic inflammatory condition and this causes an increase in the incidence of cancer of the uterus and colon, along with many other cancers.

Physical Limitations [back to top]
Morbidly obese people cannot typically do the same things that others can. Sporting activities are usually not an option and this excludes patients from activities with children and other family members. Physical activity is made difficult because of bad knees, hips, and ankles. Shortness of breath and generalized weakness make housework or employment very difficult in many situations.

Buying clothes is difficult, and many morbidly obese individuals cannot get into and out of cars easily or use seats in buses, airplanes, or movie theaters.
Flexibility is reduced and it can be more and more difficult to reach toes and taking care of personal hygiene can be a very important problem.

Social Isolation [back to top]
It is no shock that most people who are morbidly obese feel embarrassed in public. People around them are looking at them and constantly judging them with comments about their weight and the way they dress and move. This makes them withdraw and live within the surroundings of their family, who are already accustomed to them and this allows them to avoid the public gaze. This provides short term gains provided by avoiding ridicule, but this comes at a tremendous cost - inability to work, opportunity to join family in outside activities and to join friends socially.

They oftentimes have family members who have slowly adapted to their size and lifestyle by shopping for them, buying groceries and food for them, and taking care of their business.

As a consequence of the social isolation, morbidly obese people usually have low self esteem and a feeling of worthlessness and uselessness and they commonly suffer from depression. They hate their appearance and feel that they are unattractive to their partner and others.


Section 3. The Benefits of Weight Loss [back to top]

Obesity is clearly associated with an increased risk of health problems and dying. There is strong evidence that weight loss reduces risk factors for diabetes and blood vessel disease. Weight loss also improves many other medical problems and your quality of life.

There is good evidence that weight loss reduces blood pressure. It also reduces serum triglycerides and increases HDL cholesterol (good cholesterol); and generally produces some reduction in total serum cholesterol and LDL cholesterol (bad cholesterol).

Weight loss also reduces blood sugar levels in non-diabetic overweight and obese persons. It reduces blood sugar levels and HbA1c (marker of long-term sugar control) in patients with type 2 diabetes.

Weight Loss Surgery Effects on Health Problems [back to top]
Weight loss surgery is clearly one of the most powerful therapies available in medicine today. There are no other treatments which make such dramatic improvements in medical problems and no other therapy which improves the quality of life to such an extent.

It was already outlined that obesity causes or exacerbates many diseases. A plausible argument can then be made that weight loss will make all of the problems go away. Unfortunately, it is not quite this simple. Obesity may have already caused irreversible damage in some disease processes that have been present for a long time.

Type 2 diabetes is a classic obesity disease. Most patients with diabetes are overweight and about half have a BMI 31 or greater. A patient with BMI of 35 or greater has a 90-fold increased risk of diabetes compared to an individual with a BMI of 21. There are now at least 17 million patients with type 2 diabetes in the United States and a similar number of people with pre-diabetes. For patients who have had diabetes for 2 years or less, adjustable gastric band surgery resolves diabetes 73% of the time within 2 years. Gastric bypass and duodenal switch have also shown profound improvement of diabetes within 1 year of surgery.

High blood pressure is a risk factor for heart attacks and stroke and occurs much more commonly in the obese. More than two-thirds of patients have normal blood pressure off all medications shortly after surgery, and most of the rest of the patients have blood pressure that is easier to control.

Abnormal lipids in the blood, including triglycerides and HDL cholesterol, frequently return to normal levels.

Reflux esophagitis is very common in obese patients. About 90% of all patients have resolution of this disease process after weight loss surgery.

Obstructive sleep apnea, which causes nighttime snoring, daytime sleepiness, and poor quality of sleep is present in at least half of morbidly obese patients. For most patients, the snoring goes away, sleep improves markedly, and tiredness is no longer an issue after surgery.

Asthma has recently been shown to associate with obesity. In some cases after surgery there may be no further attacks or need for ongoing therapy.

NASH (non-alcoholic steatohepatitis) is an inflammation of the liver caused by obesity which is not related to alcohol consumption. This occurs in patients who have central obesity (apple-shape) and is completely resolved in most patients after surgery.

Infertility and Polycystic Ovary Syndrome is a condition associated with elevated male hormone (testerosterone) which leads to acne and excess facial and body hair. This syndrome is associated with infertility and almost all patients improve after weight loss surgery.

Arthritis is extremely common in obese individuals and, unfortunately, in many cases there is already permanent damage to the cartilage of weight bearing joints. However, pain improves and the capacity to improve performance and longevity of joints is improved.

Weight Loss Surgery Effects on Risk of Dying [back to top]
On a day to day basis, your risk of dying while morbidly obese is very low. However, as was pointed out in the chart in Section 2, the risk of dying every day for a person with BMI > 40 is significantly greater than for one with a normal BMI.

It has been clear for some time that weight loss improves risk factors for blood vessel health, including diabetes, high blood pressure, and cholesterol. However, because obesity is a chronic disease it takes time for some of these risk factors to translate into a higher rate of death in patients who remain morbidly obese.

There are now several studies which have compared large groups of patients who have had surgery with large groups of patients of similar starting BMI who didn't have surgery. These studies have all shown unequivocally that weight loss surgery patients have a lower risk of dying than similar weight patients who didn't have surgery.

In one study from Canada, a large group of weight loss surgery patients was compared with another group of patients who did not have surgery. The group undergoing weight loss surgery experienced an 89% reduction in death in the 5 years after surgery compared to the group without surgery.

More recently published in August 2007, the Swedish Obesity Subjects long-term follow-up study which compared over 2000 patients have weight loss surgery in the early 1990s with over 2000 patients who did not have surgery has also documented significantly lower mortality in patients having surgery.
Data based on patients who underwent laparoscopic adjustable gastric banding in Australia compared with matched patients who did not have surgery provide some of the strongest evidence that weight loss surgery lowers the risk of dying.

In this study, 4 patients out of 966 laparoscopic adjustable gastric band patients died during an average of 3.6 years of follow-up, while 225 out of 2119 control patients died during an average of 12.3 years of follow-up. When adjusted for age, BMI, and length of follow-up, this represents a 72% lower hazard of death from all causes for patients who had laparoscopic adjustable gastric band surgery. This means that patients not having weight loss surgery died between 3 and 4 times as frequently as patients who did.

Each of these studies always includes the deaths linked to the operation, which, unfortunately, do rarely occur near the time of surgery. The most important take-home message from these studies is that obesity itself is more dangerous than bariatric surgery.

For patients concerned about the risk of dying at the time of surgery, we know that, in general, the risk of dying within 30 days of surgery after weight loss surgery fell 78.7% (from 0.89% to 0.19%) between 1998 and 2004. This reflects the improvements in systems of bariatric care, techniques of surgery, and increased numbers of weight loss operations being performed.

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