Approach to Patients With Obesity

Introduction

The clinical management of obesity can be challenging in primary care. Clinicians are often busy and feel ill-equipped to address the disease and may therefore be unable to treat it. However, given that more than 70% of the adult US population has either overweight or obesity and the majority suffer from at least one or more weight-related comorbidity, it is a disease that primary care physicians (PCPs) and other practitioners must address.

The treatment of obesity is based on both the clinical and laboratory assessment of each patient. Combining this information can provide an assessment of the severity of the obesity, determine the associated risks and guide an appropriate and individualized treatment approach.

Weight-Specific History

A medical evaluation must include specific questions about the person’s weight and lifestyle in order to develop an individualized treatment plan.

• Review of the patients’ current weight as well as his/her highest adult weight and lowest weight.
• Review of any specific periods of weight gain. Patients will often be able to pinpoint life events (marriage, child birth, new job, relocation, a death in the family) which may have been associated with significant lifestyle changes and or psychosocial stressors which triggered weight gain. In addition, determining whether the weight gain began in childhood can help determine whether the patient needs an evaluation for secondary causes of obesity.
• What type of diets has the patient tried in the past? How many times has the patient attempted weight loss and did it work? It is important to understand what works well for the patient and to determine if the patient’s weight cycles. By examining a weight-cycling history, the clinician can try to understand the previous challenges faced both in losing the weight but more importantly, with maintaining weight loss. Once this is discussed, the clinician can help determine what approach might work best for each patient.
• Review the patient’s current dietary habits including general habits (do they skip breakfast or eat one large meal per day?), review frequency of eating out vs home meal preparation and determine who does the usual grocery shopping (to help determine whether patients have a perceived lack of control over their own intake).
• Review related psychiatric history, including anxiety or depression, which may translate into disordered eating habits. Determine whether the patient may suffer from binge eating or other maladaptive eating patterns (binge-purge, night-eating) as these may require further referral to a mental health specialist. Often patients may be ashamed of some of their behaviors but it is imperative to assess these in order to tailor the treatment plan and identify barriers to success.
• Evaluate the patient’s physical lifestyle. It is important to determine whether the patient has a sedentary lifestyle, whether he/she exercises and how you may be able to improve his/her physical activity and incorporate it into his/her daily life (e.g., you may be able to encourage the patient to walk where the patient would have otherwise driven, encourage the patient to use the stairs vs elevator, etc.). It is important to uncover whether there are barriers in the patient’s ability to perform activities (e.g., osteoarthritis [OA] of the knees) and help address these issues as part of the treatment plan.
• Diet recall—it is important to fully understand the patient’s daily food choices and portions. There are a number of tools including a 24-hour diet recall, food frequency questionnaire and/or food journal which can help make a basic assessment. It is also important to note frequency and quantity of both liquid/caloric drinks as well as alcohol intake.

Review of Weight-Promoting Medications

Certain medications can cause weight gain and increase body fat, thereby making weight loss more difficult. Table 5-1 provides a partial list of drugs and drug classes that contain medications associated with weight gain. These drugs differ in their propensity to increase body weight. The mechanism responsible for medication-induced weight gain has not been carefully studied for most of these agents, but must be related to an increase in energy intake (e.g., antipsychotics and steroid hormones), a decrease in energy expenditure (e.g., β-adrenergic receptor blockers), a decrease in energy loss (e.g., decreased glycosuria from diabetes therapy), or a combination of these factors. Weight-loss therapy can be facilitated by decreasing the dose or substituting the medication with another drug that has less weight gain potential, if possible.

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Diagnosing Overweight and Obesity

The first step in creating a comprehensive treatment plan is to evaluate the patient. In addition to a typical history (which includes the patient’s medical and surgical history, family history, social history, allergies and medications) the clinical evaluation of a patient with overweight or obesity should include specific questions about the person’s weight and lifestyle, weight-promoting medication history as well as the evaluation of body mass index (BMI), waist circumference and a complete physical examination.

BMI

Measuring the BMI is the first step to determine the degree of adiposity. BMI can be calculated quickly and without expensive equipment. More importantly, it can identify patients with increased risk of morbidity and mortality.

However, BMI is an imperfect measure of health as the categories do not take into account many factors such as muscularity and frame size. BMI is particularly inaccurate for people who are fit or athletic, as the higher muscle mass tends to put them in the overweight category by BMI, even though their body fat percentages frequently fall in a normal range. BMI also does not account for body frame size; a person may have a small frame and be carrying more adipose than optimal, but their BMI may fall in the normal range. Conversely, a large-framed individual may be quite healthy with a fairly low body fat percentage but be classified as overweight by BMI. Similarly, BMI cutoffs for identifying excess adiposity and risk of cardiometabolic disease are lower for some ethnicities. Specifically, a lower BMI threshold for screening of obesity is recommended in South Asian, Southeast Asian and East Asian adult populations based on the evidence that lower BMI values are correlated with risk of type 2 diabetes (T2D) in these ethnicities.

Despite this, BMI categories are regarded as a satisfactory tool for measuring whether individuals have underweight, overweight, or obesity. To estimate BMI, multiply the individual’s weight (in pounds) by 703, then divide by the height (in inches) squared. This approximates BMI in kilograms per meter squared (kg/m²) (Table 5-2).

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Waist Circumference and Waist-Hip Ratio

Although BMI has traditionally been the chosen indicator by which to measure body size, alternative measures that reflect abdominal adiposity, such as waist circumference, waist-hip ratio and waist-height ratio, have been suggested as being superior to BMI in predicting cardiovascular disease (CVD) risk.

Visceral fat, also known as intra-abdominal fat, is located inside the peritoneal cavity, in between internal organs and the torso, as opposed to subcutaneous fat‚ which is found underneath the skin and intramuscular fat‚ which is found interspersed in skeletal muscle. An excess of visceral fat is known as central obesity. Increased visceral adipose tissue is associated with a range of metabolic abnormalities, including decreased glucose tolerance, reduced insulin sensitivity and adverse lipid profiles, which are risk factors for T2D and CVD.

The absolute waist circumference (>102 cm [40 in] in men and >88 cm [35 in] in women) and the waist-hip ratio (>0.9 for men and >0.85 for women) are both used as measures of central obesity. Waist circumference measurement is particularly useful in patients who are categorized as normal or overweight. Men who have waist circumferences >40 inches, and women who have waist circumferences >35 inches, are at higher risk. Individuals with waist circumferences greater than these values should be considered one risk category above that defined by their BMI. Measuring the waist circumference is not necessary in patients with BMI ≥35 because patients in this BMI category are already at increased risk.

According to the NIH guide to obesity (NHLBI Obesity Education Initiative, 2000), the waist circumference measurement should be made at the top of the iliac crest with the measuring tape held snuggling at a level parallel to the floor. The patient should stand with their feet close together, arms at the side and body weight evenly distributed. Waist circumference should be measured at the end of a normal expiration, when the lungs are at their functional residual capacity. Each measurement should be repeated twice; if the measurements are within 1 cm of one another, the average should be calculated. If the difference between the two measurements exceeds 1 cm, the two measurements should be repeated.

Percent Body Fat

Since the pathology of obesity is increased when both the number and size of adipose cells are increased, estimation of body fat percentage is a useful step during risk assessment. Body fat percentage is the total mass of fat divided by total weight. Total body fat includes essential body fat and storage body fat. Essential body fat is necessary to maintain life and reproductive functions. The percentage of essential body fat for women is greater than that for men, due to the demands of childbearing and other hormonal functions. The percentage of essential fat is 2% to 5% in men, and 10% to 13% in women. Storage body fat consists of fat accumulation in adipose tissue, part of which protects internal organs in the chest and abdomen. The minimum recommended total body fat percentage exceeds the essential fat percentage value reported above. A number of methods are available for determining body fat percentage, such as measurement with calipers, bioelectrical impedance analysis and dual energy x-ray absorptiometry (DXA, formerly DEXA).

Suggested body fat percentages have been proposed (Table 5-3) and the numbers vary based on sex, age and ethnicity.

The skin-fold estimation methods are based upon a test whereby a pinch of skin is precisely measured by calipers at several standardized points on the body to determine the subcutaneous fat layer thickness.⁴ These measurements are converted to an estimated body fat percentage by an equation. Some formulas require as few as three measurements, others as many as seven. The accuracy of these estimates is more dependent on a person’s unique body fat distribution than on the number of sites measured. Although it may not give an accurate reading of real body fat percentage, it is a reliable measure of body composition change over a period of time, provided the test is carried out by the same person with the same technique.

DXA is a method for estimating body fat percentage, and determining body composition and bone mineral density. X-rays of two different energies are used to scan the body, one of which is absorbed more strongly by fat than the other. A computer can subtract one image from the other, and the difference indicates the amount of fat relative to other tissues at each point. A sum over the entire image enables calculation of the overall body composition.

The bioelectrical impedance analysis (BIA) method is a low-cost way to estimate body fat percentage. The general principle behind BIA: two or more conductors are attached to a person’s body and a small electric current is sent through the body. The resistance between the conductors will provide a measure of body fat between a pair of electrodes, since the resistance to electricity varies between adipose, muscular and skeletal tissue. Fat-free mass (muscle) is a good conductor as it contains a large amount of water (approximately 73%) and electrolytes, while fat is anhydrous and a poor conductor of electric current. Factors that affect the accuracy and precision of this method include instrumentation, subject factors, technician skill and the prediction equation formulated to estimate the fat-free mass. There is little scope for technician error, but factors such as eating, drinking and exercising must be controlled since hydration level is an important source of error in determining the flow of the electric current to estimate body fat.

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Office Equipment and Atmosphere

The care of patients with obesity requires an appropriately equipped office free of bias. The patient should feel welcomed and comfortable as soon as they enter the office. It is very important to treat the patient with respect and make them feel physically and emotionally comfortable. The office should have appropriately sized chairs in both the waiting room and in the exam rooms, wider scales with hand bars to hold onto that can be used for patients up to at least 500 lb, appropriate exam tables, long tape measures, highly adjustable BP cuffs and gowns of appropriate sizing. All staff members should receive training on weight bias and stigma to help ensure each patient is treated appropriately and with respect.

Physical Examination

The physical exam should be focused on both characterizing obesity, as well as looking for causes and associated complications. As mentioned above, the patients’ height and weight should be carefully measured and recorded in addition to their waist circumference. The patients’ vital signs should be taken with special care to the fact that they may need specialized equipment to determine accurate readings. In assessing the BP, it is important to use an accurate size cuff because if it is too narrow, the BP may be falsely elevated. The cuff should be approximately 40% to 50% of the upper arm circumference. The clinician may need either a large adult cuff or thigh cuff, depending on the patient.

A routine physical exam should be performed in a supportive and nonthreatening manner. Attention should be paid towards looking for associated medical conditions including thin, atrophic skin (a feature of Cushing’s disease), hyperpigmented skin around the neck or axilla (acanthosis nigricans, associated with insulin resistance), large neck circumference (increased risk of obstructive sleep apnea (OSA) and hirsutism (may indicate polycystic ovarian syndrome).

Laboratory Evaluation

Basic laboratory evaluation should include examination for obesity-related conditions. This should include a fasting plasma glucose, fasting lipid panel, thyroid stimulating hormone (TSH; thyroid function modulates weight), liver transaminases to look for non-alcoholic steatohepatitis (NASH), as well as basic metabolic panel (to assess kidney function). Laboratory testing for specific disease and medication should be done depending on the patient history. For example, hemoglobin A1C (A1C) is important to monitor in patients with diabetes and their response to treatment.

Baseline Laboratory Evaluation

• Fasting plasma glucose
• Fasting lipid panel (total cholesterol, LDL, HDL, triglycerides)
• TSH and free thyroxine
• Complete metabolic panel (for ALT, AST, creatinine, BUN and electrolytes)
• A1C and fasting insulin
• Complete blood counts

Further evaluation for endocrine or genetic causes and related comorbidities may be warranted depending on the patient’s medical history and physical exam. For example, depending on the physical exam, a work-up for Cushing’s disease may be warranted (central obesity, abdominal striae, moon facies, buffalo hump) and this can be done with either a 24-hour urinary free cortisol or an overnight dexamethasone suppression test.

Evaluation for Weight-Related Comorbidities

Upon completion of the basic medical assessment, additional medical problems may be unmasked. In patients with obesity, many of these conditions should be further evaluated as they may complicate or alter the treatment plan:

• Respiratory—hypoventilation syndromes are common in patients with obesity and include both OSA and obesity hypoventilation syndrome. These conditions can lead to pulmonary hypertension, arrhythmias and depression. The risk for OSA can quickly be assessed by using the STOP-BANG questionnaire (Figure 5-1) or the Epworth Sleepiness Scale (Figure 5-2). It is important to promptly evaluate for these conditions with the appropriate referrals for either a sleep study or to a sleep medicine specialist for further evaluation and treatment.
• Cardiovascular—the American Heart Asso­ciation classifies obesity as a major modifiable risk factor for coronary heart disease, independent of its comorbidities. Specific comorbid conditions may include coronary artery disease, hypertension, left ventricular hypertrophy, cor pulmonale and obesity-associated cardiomyopathy.
• Gastrointestinal—common complications include nonalcoholic fatty liver disease (fatty liver infiltration, NASH) and reflux esophagitis.
• Orthopedic—many patients suffer from OA which may limit their physical functioning and ability to perform an exercise program.
• Metabolic—numerous metabolic disturbances may be found including T2D, prediabetes, metabolic syndrome and dyslipidemia. These conditions should be aggressively managed during the course of any weight loss intervention.
• Reproductive—women often have weight-related reproductive challenges including anovulation, early puberty, infertility, hyperandrogenism, polycystic ovaries and pelvic stress incontinence. Screening and appropriate referrals should be made as needed.
• Cutaneous—intertrigo (bacterial and/or fungal) is a common challenge faced by patients with obesity. It is important to assess and subsequently counsel patients on good hygiene to prevent further complications.
• Psychiatric—major psychiatric illness may present an obstacle or even contraindication to treatment. A common finding is mild-moderate depression and patients should be screened and may require behavioral therapy and/or medication with referral to psychiatry depending on the severity.

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Disease Staging and Risk Assessment

The patient’s risk status should be assessed by determining the degree of overweight or obesity based on BMI, the presence of abdominal obesity based on waist circumference and the presence of concomitant CVD risk factors or comorbidities. Some obesity-associated diseases and risk factors place patients in a very high-risk category for subsequent mortality. These diseases will require aggressive modification of risk factors in addition to their own clinical management.

Much, if not most, of the relevant information for clinical risk assessment and disease staging of patients with overweight/obesity is readily available to the clinician in routine clinical practice. Additional information can be obtained from several validated assessment and disease staging tools such as the Edmonton Obesity Staging System (EOSS).

Assessment of Motivation

Before initiating a treatment plan, it is important to determine whether a patient is ready to make the necessary changes, as not all patients are ready to lose weight. When counseling the patient, the plan should be individualized to their specific needs and allow for flexibility in order to prevent the patient from feeling like a failure.

Realistic Goal Setting

Patients often have unrealistic expectations about how much weight they would like to lose. It is not necessary to achieve an “ideal” body weight or normal BMI because health benefits are often achieved when a patient loses as little as 5% to 10% of their total body weight. The rate of weight loss is not necessarily important, however, usual goals target approximately 1-2 lb/week over the course of 6 months. Goal setting should occur in conjunction with the patient and may be modified over time. Weight loss alone should not be the only aim of treatment, rather improvement in obesity-related comorbidities should be a primary goal and monitored throughout treatment . Long-term treatment plans should be in place to assist with weight maintenance and avoidance of weight regain.

Creating a Treatment Plan

The treatment of obesity should be based upon the degree of adiposity and the prevalence and risks of weight-related comorbidities. A higher risk patient may require a more aggressive intervention such as pharmacotherapy and surgery. All plans should be flexible to accommodate an individual’s needs and preferences. The Algorithm for the Medical Care of Patients with Obesity published by the American Association of Clinical Endocrinologists (AACE) and American College of Endocrinology (ACE) in 2016 provides an obesity-specific treatment algorithm for the management of patients with overweight or obesity.

In addition, Figure 5-3 is the treatment algorithm from the 2013 AHA/ACC/TOS Guideline For The Management Of Overweight And Obesity In Adults. It is based on the Chronic Disease Management Model for Primary Care of Patients with Overweight and Obesity to guide PCPs in the evaluation, prevention and management of patients regarding excess body weight. The algorithm is not intended to supplant initial assessment for CV risk factors or diseases but rather focuses on the identification of patients with excess body weight and those at risk for obesity-related health problems. Its purpose is to guide weight management decision making. This intervention should be a foundation for additional weight management efforts, such as addition of medications or bariatric surgery.

All treatment programs should include a comprehensive team approach and may include a physician, registered dietician, social worker, psychiatrist, nurse and surgeon. Effective management requires sufficient time and frequent monitoring in order to keep the patient motivated and provide accountability. Once a patient achieves a reasonable goal weight, it may take as much, if not more, time to maintain the weight loss. Given that obesity is a chronic disease, it is paramount that patients have long-term monitoring in order to help prevent weight regain.

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