Morbid Obesity and Weight Loss Information from Coastal Bariatrics in Foley, Alabama

What Is Obesity?
Obesity results from the excessive accumulation of fat that exceeds the body's skeletal and physical standards. According to the National Institutes of Health (NIH), an increase in 20 percent or more above your ideal body weight is the point at which excess weight becomes a health risk. Today 97 million Americans, more than one-third of the adult population, are overweight or obese. An estimated 5 to 10 million of those are considered morbidly obese.

What Is Morbid Obesity?
Obesity becomes "morbid" when it reaches the point of significantly increasing the risk of one or more obesity-related health conditions or serious diseases (also known as co-morbidities) that result either in significant physical disability or even death. As you read about morbid obesity you may also see the term "clinically severe obesity" used. Both are descriptions of the same condition and can be used interchangeably. Morbid obesity is typically defined as being 100 lbs. or more over ideal body weight or having a Body Mass Index of 40 or higher. According to the National Institutes of Health Consensus Report, morbid obesity is a serious disease and must be treated as such. It is a chronic disease, meaning that its symptoms build slowly over an extended period of time. Obesity treatment is available, and weight loss surgery may be a good option for you.

Causes of Morbid Obesity
The reasons for obesity are multiple and complex. Despite conventional wisdom, it is not simply a result of overeating. Research has shown that in many cases a significant, underlying cause of morbid obesity is genetic. Studies have demonstrated that once the problem is established, efforts such as dieting and exercise programs have a limited ability to provide effective long-term relief.

Science continues to search for answers. But until the disease is better understood, the control of excess weight is something patients must work at for their entire lives. That is why it is very important to understand that all current medical interventions, including weight loss surgery, should not be considered medical cures. Rather they are attempts to reduce the effects of excessive weight and alleviate the serious physical, emotional and social consequences of the disease.

Contributing Factors
The underlying causes of severe obesity are not known. There are many factors that contribute to the development of obesity including genetic, hereditary, environmental, metabolic and eating disorders. There are also certain medical conditions that may result in obesity like intake of steroids and hypothyroidism.

Numerous scientific studies have established that your genes play an important role in your tendency to gain excess weight.
The body weight of adopted children shows no correlation with the body weight of their adoptive parents, who feed them and teach them how to eat. Their weight does have an 80 percent correlation with their genetic parents, whom they have never met.
Identica twins, with the same genes, show a much higher similarity of body weights than do fraternal twins, who have different genes.
Certain groups of people, such as the Pima Indian tribe in Arizona, have a very high incidence of severe obesity. They also have significantly higher rates of diabetes and heart disease than other ethnic group.

We probably have a number of genes directly related to weight. Just as some genes determine eye color or height, others affect our appetite, our ability to feel full or satisfied, our metabolism, our fat-storing ability, and even our natural activity levels.

The Pima Paradox
The Pima Indians are known in scientific circles as one of the heaviest groups of people in the world. In fact, National Institutes of Health researchers have been studying them for more than 35 years. Some adults weigh more than 500 pounds, and many obese teenagers are suffering from diabetes, the disease most frequently associated with obesity. But here's a really interesting fact - a group of Pima Indians living in Sierra Madre, Mexico, does not have a problem with obesity and its related diseases. Why not?

The leading theory states that after many generations of living in the desert, often confronting famine, the most successful Pima were those with genes that helped them store as much fat as possible during times when food was available. Now those fat-storing genes work against them. Though both populations consume a similar number of calories each day, the Mexican Pima still live much like their ancestors did. They put in 23 hours of physical labor each week and eat a traditional diet that's very low in fat. The Arizona Pima live like most other modern Americans, eating a diet consisting of around 40 percent fat and engaging in physical activity for only two hours a week.

The Pima apparently have a genetic predisposition to gain weight. And the environment in which they live - the environment in which most of us live - makes it nearly impossible for the Arizona Pima to maintain a normal, healthy body weight.

Environmental Factors
Environmental and genetic factors are obviously closely intertwined. If you have a genetic predisposition toward obesity, then the modern American lifestyle and environment may make controlling weight more difficult.Fast food, long days sitting at a desk, and suburban neighborhoods that require cars all magnify hereditary factors such as metabolism and efficient fat storage.For those suffering from morbid obesity, anything less than a total change in environment usually results in failure to reach and maintain a healthy body weight.

Metabolism
We used to think of weight gain or loss as only a function of calories ingested and then burned. Take in more calories than you burn, gain weight; burn more calories than you ingest, lose weight. But now we know the equation isn't that simple.

Obesity researchers now talk about a theory called the "set point," a sort of thermostat in the brain that makes people resistant to either weight gain or loss. If you try to override the set point by drastically cutting your calorie intake, your brain responds by lowering metabolism and slowing activity. You then gain back any weight you lost.

Eating Disorders & Medical Conditions
Weight loss surgery is not a cure for eating disorders. And there are medical conditions, such as hypothyroidism, that can also cause weight gain. That's why it's important that you work with your doctor to make sure you do not have a condition that should be treated with medication and counseling.

Obesity-Related Health Conditions
Obesity-related health conditions are health conditions that, whether alone or in combination, can significantly reduce your life expectancy. A partial list of some of the more common conditions follows. Your doctor can provide you with a more detailed and complete list:

Type 2 Diabetes:Obese individuals develop a resistance to insulin, which regulates blood sugar levels. Over time, the resulting high blood sugar can cause serious damage to the body.
High blood pressure/Heart disease:Excess body weight strains the ability of the heart to function properly. The resulting hypertension (high blood pressure) can result in strokes, as well as inflict significant heart and kidney damage.
Osteoarthritis of weight-bearing joints:The additional weight placed on joints, particularly knees and hips, results in rapid wear and tear, along with pain caused by inflammation. Similarly, bones and muscles of the back are constantly strained, resulting in disk problems, pain and decreased mobility.
Sleep apnea/Respiratory problems:Fat deposits in the tongue and neck can cause intermittent obstruction of the air passage. Because the obstruction is increased when sleeping on your back, you may find yourself waking frequently to reposition yourself. The resulting loss of sleep often results in daytime drowsiness and headaches.
Gastroesophageal reflux/Heartburn:Acid belongs in the stomach and seldom causes any problem when it stays there. When acid escapes into the esophagus through a weak or overloaded valve at the top of the stomach, the result is called gastroesophageal reflux, and "heartburn" and acid indigestion are common symptoms. Approximately 10-15% of patients with even mild sporadic symptoms of heartburn will develop a condition called Barrett's esophagus, which is a pre-malignant change in the lining membrane of the esophagus, a cause of esophageal cancer. For more information on Heartburn, its causes and possible cures, visit www.heartburnhelp.com.
Depression:Seriously overweight persons face constant challenges to their emotions: repeated failure with dieting, disapproval from family and friends, sneers and remarks from strangers. They often experience discrimination at work, cannot fit comfortably in theatre seats, or ride in a bus or plane.
Infertility:The inability or diminished ability to produce offspring.
Urinary stress incontinence:A large, heavy abdomen and relaxation of the pelvic muscles, especially associated with the effects of childbirth, may cause the valve on the urinary bladder to be weakened, leading to leakage of urine with coughing, sneezing, or laughing.
Menstrual irregularities: Morbidly obese individuals often experience disruptions of the menstrual cycle, including interruption of the menstrual cycle, abnormal menstrual flow and increased pain associated with the menstrual cycle.

Options for Treatment
For anyone who has considered a weight loss program, there is certainly no shortage of choices. In fact, to qualify for insurance coverage of weight loss surgery, many insurers require patients to have a history of medically supervised weight loss efforts. Most non-surgical weight loss programs are based on some combination of diet/behavior modification and regular exercise. Unfortunately, even the most effective interventions have proven to be effective for only a small percentage of patients. It is estimated that less than 5% of individuals who participate in non-surgical weight loss programs will lose a significant amount of weight and maintain that loss for a long period of time.

According to the National Institutes of Health, more than 90% of all people in these programs regain their weight within one year. Sustained weight loss for patients who are morbidly obese is even harder to achieve. Serious health risks have been identified for people who move from diet to diet, subjecting their bodies to a severe and continuing cycle of weight loss and gain known as "yo-yo dieting." The fact remains that morbid obesity is a complex, multifactorial chronic disease. For many patients, the risk of death from not having the surgery is greater than the risks from the possible complications of having the procedure.

That is the key reason that in 2000, approximately 40,000 weight loss surgery procedures were performed and why the American Society for Bariatric Surgery estimates that 50,000 weight loss surgical procedures will be performed in 2001. Patients who have had the procedure and are benefiting from its results report improvements in their quality of life, social interactions, psychological well-being, employment opportunities and economic condition. In clinical studies, candidates for the procedure who had multiple obesity-related health conditions questioned whether they could safely have the surgery. These studies show that selection of surgical candidates is based on very strict criteria and weight loss surgery is an option for the majority of patients.

Weight Loss Surgery
Weight loss surgery is major surgery. Its growing use to treat morbid obesity is the result of three factors:

Surgery should be viewed first and foremost as a method for alleviating debilitating, chronic disease. In most cases, the minimum qualification for consideration as a candidate for the procedure is 100 lbs. above ideal body weight or those with a Body Mass Index of 40 or greater. Occasionally a procedure will be considered for someone with a BMI of 35 or higher if the patient's physician determines that obesity-related health conditions have resulted in a medical need for weight reduction and, in the doctor's opinion, surgery appears to be the only way to accomplish the targeted weight loss. In many cases, patients are required to show proof that their attempts at dietary weight loss have been ineffective before surgery will be approved. More important, however, is the commitment on the part of the patient to required, long-term follow-up care. Most surgeons require patients to demonstrate serious motivation and a clear understanding of the extensive dietary, exercise and medical guidelines that must be followed for the remainder of their lives after having weight loss surgery.

Diet & Behavior Modification
There are literally hundreds of diets available. Moving from diet to diet in a cycle of weight gain and loss - yo-yo dieting - that stresses the heart, kidneys and other organs can also be a health risk. Doctors who prescribe and supervise diets for their patients usually create a customized program with the goal of greatly restricting calorie intake while maintaining nutrition.

Many patients on Very Low Calorie Diets lose significant amounts of weight. However, after returning to a normal diet, most regain the lost weight in under a year. Ninety percent of people participating in all diet programs will regain the weight they've lost within two years.

Behavior modification uses therapy to help patients change their eating and exercise habits. Like low-calorie diets, behavior modification, in most patients, results in short-term success that tends to diminish after the first year. If diet and behavior modifications have failed you and surgical weight loss is your next option, it is important to understand that diet and behavior modification will be instrumental to sustained weight loss after your surgery. Weight loss surgery itself is only a tool to get your body started losing weight - complying with diet and behavior modifications required by most surgeons would determine your ultimate success.

Exercise
Starting an exercise program can be especially intimidating for someone suffering from morbid obesity. Your health condition may make any level of physical exertion next to impossible. The benefits of exercise are clear, however. And there are ways to get started.

A National Institutes of Health survey of 13 studies concludes that physical activity:

New theories focusing on the body's set point (the weight range in which your body is programmed to weigh and will fight to maintain that weight) highlight the importance of exercise. When you reduce the number of calories you take in, the body simply reacts by slowing metabolism to burn fewer calories. Daily physical activity can help speed up your metabolism, effectively bringing your set point down to a lower natural weight. So when following a diet to attempt to lose weight, exercise increases your chances of long-term success.

Overall, walking is one of the best forms of exercise. Start out slowly and build up. Your doctor, or people in a support group, can offer encouragement and advice. Incorporating exercise into your daily activities will improve your overall health and is important for any long-term weight management program, including weight loss surgery. Diet and exercise play a key role in successful weight loss after surgery.

Over-the-Counter & Prescription Drugs
New over-the-counter and prescription weight loss medications have been introduced. Some people have found them effective in helping to curb their appetite. The results of most studies show that patients on drug therapy lose around 10 percent of their excess weight and that the weight loss plateaus after six to eight months. As patients stop taking the medication, weight gain usually occurs. Weight loss drugs can have serious side effects. Still, medications are an important step in the morbid obesity treatment process. Before insurance companies will reimburse/pay for weight loss surgery, you must follow a well-documented treatment path.

"Since many people cannot lose much weight no matter how hard they try, and promptly regain whatever they do lose, the vast amount of money spent on diet clubs, special foods and over-the-counter remedies, estimated to be on the order of $30 billion to $50 billion yearly, is wasted." (New England Journal of Medicine)

Weight Loss Surgery Options
The American Society for Bariatric Surgery describes two basic approaches that weight loss surgery takes to achieve change:

Laparoscopic or Minimally Invasive Surgery
For the last decade, laparoscopic procedures have been used in a variety of general surgeries. Many people mistakenly believe that these techniques are still "experimental." In fact, laparoscopy has become the predominant technique in some areas of surgery and has been used for weight loss surgery for several years.

When a laparoscopic operation is performed, a small video camera is inserted into the abdomen. The surgeon views the procedure on a separate video monitor. Most laparoscopic surgeons believe this gives them better visualization and access to key anatomical structures.

The camera and surgical instruments are inserted through small incisions made in the abdominal wall. This approach is considered less invasive because it replaces the need for one long incision to open the abdomen. A recent study shows that patients having had laparoscopic weight loss surgery experience less pain after surgery resulting in easier breathing and lung function and higher overall oxygen levels. Other realized benefits with laparoscopy have been fewer wound complications such as infection or hernia, and patients returning more quickly to pre-surgical levels of activity.

Laparoscopic procedures for weight loss surgery employ the same principles as their "open" counterparts and produce similar excess weight loss. Not all patients are candidates for this approach, just as all bariatric surgeons are not trained in the advanced techniques required to perform this less invasive method. The American Society for Bariatric Surgery recommends that laparoscopic weight loss surgery should only be performed by surgeons who are experienced in both laparoscopic and open bariatric procedures. (See additional risk and complications.)

Gastric Restrictive Procedure - Lap-Band®
The Laparoscopic Adjustable Gastric Banding or Lap-Band® System is the newest breakthrough in the treatment of Morbid Obesity and the only device of its kind approved for use in the United States. Although relatively new in the United States, it has been used for approximately 10 years in Europe Countries and Mexico. This purely restrictive procedure limits solid food intake by surgically inserting an inflatable band completely around the uppermost part of the stomach. Such restriction induces weight loss by reducing the capacity of the stomach's upper created pouch and delays food from emptying into the lower stomach. As a result, patients experience an earlier sensation of fullness and are satisfied with smaller amounts of food.

It provides a less traumatic procedure since there is no cutting or stapling of the stomach and there is no rerouting of the intestines.
The primary advantage of the Lap-Band® System is that the diameter of the band is adjustable to meet your individual needs, which can change as you lose weight. For example, pregnant patients can expand their band to accommodate a growing fetus, while patients who aren't experiencing significant weight loss can have their bands tightened. To modify the size of the band, its inner surface can be inflated or deflated with saline solution. The band is connected by tubing to a reservoir, which is placed well under the skin during surgery. After the operation, the surgeon can control the amount of saline in the band by entering the reservoir with a fine needle through the skin
The Lap-Band® System allows for full absorption of the nutrients and vitamins obtained from the food eaten (as well as the calories).

The band applied may lead to complications of obstruction or perforation, requiring surgical intervention.
Because restrictive procedures rely solely on a small stomach pouch to reduce food intake, there is the risk of the pouch stretching or of the restricting band at the pouch outlet breaking or migrating, thus allowing patients to eat too much.
As is the case with all weight loss surgeries, readmission to a hospital may be required for fluid replacement or nutritional support if there is excessive vomiting and adequate food intake cannot be maintained.
The band applied may lead to complications of obstruction or perforation, requiring surgical intervention.
Around 40% of patients undergoing these procedures have lost less than half their excess body weight.
Additional procedure necessary to fix a leaking or twisted access port. The access port design has been improved.
1.3% of patients had their bands erode into their stomachs. These bands needed to be removed in a second operation.

Combined Restrictive & Malabsorptive Procedure - Roux-en-Y Gastric Bypass
In recent years, better clinical understanding of procedures combining restrictive and malabsorptive approaches has increased the choices of effective weight loss surgery for thousands of patients. By adding malabsorption, food is delayed in mixing with bile and pancreatic juices that aid in the absorption of nutrients. The result is an early sense of fullness, combined with a sense of satisfaction that reduces the desire to eat.

According to the American Society for Bariatric Surgery and the National Institutes of Health, Roux-en-Y gastric bypass is the current gold standard procedure for weight loss surgery. It is one of the most frequently performed weight loss procedures in the United States. In this procedure, stapling creates a small (15 to 20cc) stomach pouch. The remainder of the stomach is not removed, but is completely stapled shut and divided from the stomach pouch. The outlet from this newly formed pouch empties directly into the lower portion of the jejunum, thus bypassing calorie absorption. This is done by dividing the small intestine just beyond the duodenum for the purpose of bringing it up and constructing a connection with the newly formed stomach pouch. The other end is connected into the side of the Roux limb of the intestine creating the "Y" shape that gives the technique its name. The length of either segment of the intestine can be increased to produce lower or higher levels of malabsorption.

The average excess weight loss after the Roux-en-Y procedure is generally higher in a compliant patient than with purely restrictive procedures.
One year after surgery, weight loss can average 77% of excess body weight.
Studies show that after 10 to 14 years, 50-60% of excess body weight loss has been maintained by some patients.
A 2000 study of 500 patients showed that 96% of certain associated health conditions studied (back pain, sleep apnea, high blood pressure, diabetes and depression) were improved or resolved.

Because the duodenum is bypassed, poor absorption of iron and calcium can result in the lowering of total body iron and a predisposition to iron deficiency anemia. This is a particular concern for patients who experience chronic blood loss during excessive menstrual flow or bleeding hemorrhoids. Women, already at risk for osteoporosis that can occur after menopause, should be aware of the potential for heightened bone calcium loss.
Bypassing the duodenum has caused metabolic bone disease in some patients, resulting in bone pain, loss of height, humped back and fractures of the ribs and hip bones. All of the deficiencies mentioned above, however, can be managed through proper diet and vitamin supplements.
A chronic anemia due to Vitamin B12 deficiency may occur. The problem can usually be managed with Vitamin B12 pills or injections.
A condition known as "dumping syndrome " can occur as the result of rapid emptying of stomach contents into the small intestine. This is sometimes triggered when too much sugar or large amounts of food are consumed. While generally not considered to be a serious risk to your health, the results can be extremely unpleasant and can include nausea, weakness, sweating, faintness and, on occasion, diarrhea after eating. Some patients are unable to eat any form of sweets after surgery.
In some cases, the effectiveness of the procedure may be reduced if the stomach pouch is stretched and/or if it is initially left larger than 15-30cc
The bypassed portion of the stomach, duodenum and segments of the small intestine cannot be easily visualized using X-ray or endoscopy if problems such as ulcers, bleeding or malignancy should occur.

Additional Risk and Complications of Surgery for Morbid Obesity
Although weight loss surgery results look promising, it is major surgery and common to all surgical procedures is the potential for unexpected outcomes or complications during or after surgery. Such complications may include, but are not limited to:

Blood clots in the leg, pelvis or elsewhere could lead to pulmonary embolism (A blood clots that migrates into the heart and lungs that can sometimes be fatal).
Gastric outlet stenosis / obstruction which may result in blockage of the stomach.
Small bowel obstruction which may result in blockage of the intestines.
Distention of the stomach.
Acute cholecystitis (inflammation and/or infection of gall-bladder.
Leaks involving stomach or intestine possibly leading to peritonitis (serious infection).
An abscess (a collection of pus) within the abdomen.
Pneumonia (infection of the lung).
Phlebitis (inflammation of the veins).
Wound dehiscence (opening up of the surgical wound).
Collection of blood, fluid or pus in the surgical wound.
Bleeding from any part of the surgery.
Breakdown of the staple line.
Bezoar obstruction (food particles causing blockage of stomach).
Psychological changes/depression.
Dysrhythmia (irregular heart beats/see above).
Many of the above complications could require the need for re-operation.
Death.

Staple line breakdown which may result in the failure of the operation.
Gastroplasty stoma obstruction (blockage of the outlet of the Gastroplasty, usually due to food).
Gastroplasty stoma stenosis (narrowing of the outlet of the Gastroplasty which may result in inability to eat properly and/or vomiting).
Gastroplasty pouch enlarging or swelling.
Gastroplasty stoma enlarging or swelling.
Ulcer formation in stomach or intestine.
Small bowel obstruction (blockage).
Hernia in the incision.
Cholelithiasis (gall stones in the gall bladder which may result in removal of the gall bladder.
Vomiting.
Diarrhea and /or foul flatulence.
Dumping syndrome with the gastric bypass procedure that may result in dizziness and nausea.
Anorexia (lack or loss of appetite).
Hypoglycemia (low sugar levels in blood).
Protein malnutrition.
Vitamin deficiencies.
Trace element deficiencies.
Partial hair loss (which is usually temporary).
Brittle nails.
Skin rashes.
Peripheral neuropathy (nerve tissue malfunction).
Central neuropathy (nerve tissue malfunction).
Psychological changes, including possible effects from new, smaller body image that could affect spouse, family and friend relationships.
Difficulty in examining the lower part of the stomach after gastric bypass.
Permanent alteration of dietary and bowel habits.
Some of the above complications could require the need for re-operation.
Death.

Choosing Surgery
Weight loss surgery is major surgery. Although most patients enjoy an improvement in obesity-related health conditions (such as mobility, self-image and self-esteem) after the successful results of weight loss surgery, these results should not be the overriding motivation for having the procedure. The goal is to live better, healthier and longer.

That is why you should make the decision to have weight loss surgery only after careful consideration and consultation with an experienced bariatric surgeon or a knowledgeable family physician. A qualified surgeon should answer your questions clearly and explain the exact details of the procedure, the extent of the recovery period and the reality of the follow-up care that will be required. They may, as part of routine evaluation for weight loss surgery, require that you consult with a dietician/nutritionist and a psychiatrist/therapist. This is to help establish a clear understanding of the post-operative changes in behavior that are essential for long-term success.

It is important to remember that there are no ironclad guarantees in any kind of medicine or surgery. There can be unexpected outcomes in even the simplest procedures. (See additional risk and complications.) What can be said, however, is that weight loss surgery will only succeed when the patient makes a lifelong commitment. Some of the challenges facing a person after weight loss surgery can be unexpected. Lifestyle changes can strain relationships within families and between married couples. To help patients achieve their goals and deal with the changes surgery and weight loss can bring, most bariatric surgeons offer follow-up care that includes support groups, dieticians and other forms of continuing education.

Ultimately, the decision to have the procedure is entirely up to you. After having heard all the information, you must decide if the benefits outweigh the side effects and potential complications. This surgery is only a tool. Your ultimate success depends on strict adherence to the recommended dietary, exercise and lifestyle changes.

Life After Surgery
The following identifies areas that will be important for patients to follow after weight loss surgery.

Diet
The modifications made to your gastrointestinal tract will require permanent changes in your eating habits that must be adhered to for successful weight loss. Post-surgery dietary guidelines will vary by surgeon. You may hear of other patients who are given different guidelines following their weight loss surgery. It is important to remember that every surgeon does not perform the exact same weight loss surgery procedure and that the dietary guidelines will be different for each surgeon and each type of procedure. What is most important is that you adhere strictly to your surgeon's recommended guidelines. The following are some of the generally accepted dietary guidelines a weight loss surgery patient may encounter:

When you start eating solid food it is essential that you chew thoroughly. You will not be able to eat steaks or other chunks of meat if they are not ground or chewed thoroughly.

Going Back to Work
Your ability to resume pre-surgery levels of activity will vary according to your physical condition, the nature of the activity and the type of weight loss surgery you had. Many patients return to full pre-surgery levels of activity within six weeks of their procedure. Patients who have had a minimally invasive laparoscopic procedure may be able to return to these activities within a few weeks.

Birth Control & Pregnancy
It is strongly advised that women of childbearing age use the most effective forms of birth control during the first 16 to 24 months after weight loss surgery. The added demands pregnancy places on your body and the potential for fetal damage make this a most important requirement.

Long-Term Follow-Up
Although the short-term effects of weight loss surgery are well understood, there are still questions to be answered about the long-term effects on nutrition and body systems. Nutritional deficiencies that occur over the course of many years will need to be studied. Over time, you will need periodic checks for anemia (low red blood cell count) and Vitamin B12, folate and iron levels. Follow-up tests will initially be conducted every three to six months or as needed, and then every one to two years.

Support Groups
The widespread use of support groups has provided weight loss surgery patients an excellent opportunity to discuss their various personal and professional issues. Most learn, for example, that weight loss surgery will not immediately resolve existing emotional issues or heal the years of damage that morbid obesity might have inflicted on their emotional well-being. Most surgeons have support groups in place to assist you with short-term and long-term questions and needs. Most bariatric surgeons who frequently perform weight loss surgery will tell you that ongoing post-surgical support helps produce the greatest level of success for their patients.