Obesity rates in the United States have skyrocketed over the last 30 years, with rates for adults having doubled and rates for children tripled from 1980 to 2010. Approximately one-third of the U.S adult population is obese; that’s 72 million people. The consequences of obesity include an increased risk for stroke, hypertension, type 2 diabetes, liver and gallbladder disease, orthopedic complications, mental health conditions, cancers, elevated lipids, obstructive sleep apnea (OSA), and reproductive complications such as infertility.
There is now solid evidence that we can intervene to help patient lose weight and decrease the complications that result from obesity. To this end, the American Association of Clinical Endocrinology (AACE) has issued recommendations giving guidance for clinicians about how to approach this issue. Intensive approaches to lifestyle modification with diet and exercise can help patients lose 7% or more of their body weight and have been show to decrease progression from prediabetes to diabetes. Two new medications, lorcaserin and phentermine/topiramate ER, have received Food and Drug Administration approval over the past 2 years as an adjunct to diet for weight loss. Bariatric surgery has emerged as a safe and effective method of weight loss as well.
The AACE guidelines focus on a "complications-centric model" as opposed to a body mass index–driven approach. The guidelines recommend treating obesity to decrease the risk of developing adverse metabolic consequences such as diabetes and metabolic syndrome, and to decrease disability from mechanical comorbidities such as osteoarthritis and obstructive sleep apnea. The AACE guidelines place obese patients into two categories: those that have obesity-related comorbidities and those that do not. The guidelines recommend a graded approach to treatment. All overweight and obese patients should receive therapeutic lifestyle counseling focusing on diet and exercise. Medical or surgical treatment is then recommended for the patients who stand to benefit the most, those with obesity-related comorbidities and those with more severe obesity who have not been able to lose weight using lifestyle modification alone.
In the initial evaluation of overweight and obese patients, the patients should be assessed for cardiometabolic and mechanical complications of obesity, as well as the severity of those complications in order to determine the level of treatment that is appropriate. Patients with obesity-related comorbidities are classified into two groups. The first group includes those with insulin resistance and/or cardiovascular consequences. For this group, evaluation should include waist circumference, fasting, and 2-hour glucose tolerance testing, and lipids, blood pressure, and liver function testing. The second group is composed of people with mechanical consequences including OSA, stress incontinence, orthopedic complications, and chronic pulmonary diseases.
It is important to determine target goals for weight loss to improve mechanical and cardiometabolic complications. Weight loss of 5% or more is enough to affect improvement in metabolic parameters such as glucose and lipids, decrease progression to diabetes, and improve mechanical complications such as knee and hip pain in osteoarthritis. The next step in the approach to treatment is to determine the type and intensity. Therapeutic lifestyle changes (TLC) are important for all patients with diabetes and prediabetes, regardless of risk factors. TLC recommendations include smoking cessation, physical activity, weight management, and healthy eating. Exercise is recommended 5 days/week for more than 30 minutes of moderate intensity activity, to achieve a more than 60% age-related heart rate. The diet recommended reduced saturated fat to less than 7% of calories, reduced cholesterol intake to 200 mg/day, increased fiber to 10-25 g/day, increased plant sterols/stanol esters to 2 g/day, caloric restriction, reduced simple carbohydrates and sugars, increased intake of unsaturated fats, elimination of trans fats, increased marine-based omega-3 ethyl esters, and restriction of alcohol to 20-30 g/day.
For patients with comorbidities and with a BMI of 27 kg/m2 or more, consideration should be given to weight-loss medication in addition to lifestyle intervention. The currently approved medications for long-term weight loss include lorcaserin and phentermine/topiramate ER. In the FDA registration studies, the lorcaserin group had an average weight loss of 5.8% after 1 year vs. 2.2% in the placebo group. Phentermine/topiramate ER had an average weight loss of 10% at 1 year vs. 1.2% in the placebo group. These medications are FDA approved as adjuncts to lifestyle modification for the treatment of overweight patients with a BMI greater than 27 kg/m2 with comorbidities and for obese patients with a BMI greater than 30 kg/m2 regardless of comorbidities. Both medications improve blood pressure, triglycerides, and insulin sensitivity and prevent the progression to diabetes in patients with diabetes. Bariatric surgery should be considered for those with a BMI of 35 kg/m2 or morewith comorbidities, especially if they have failed using other methods.