As part of comprehensive obesity treatment, family physicians should use pharmacotherapy for patients who have been unable to achieve clinically significant weight loss by means of lifestyle modification.
In 2015, the Canadian Task Force on Preventive Health Care (CTFPHC) released its “Recommendations for prevention of weight gain and use of behavioural and pharmacologic interventions to manage overweight and obesity in adults in primary care.”1 Although graded as weak, one main recommendation from the guidelines was that primary care physicians (PCPs) should not routinely offer patients pharmacologic interventions for weight loss; the guidelines state that pharmacotherapy might be warranted in some cases of obesity, but the benefits and risks need to be weighed.1 Obesity is a chronic disease, and PCPs are at the forefront of chronic disease management. The worry is that this negatively phrased recommendation might dissuade PCPs from offering pharmacotherapy to patients with excess weight who have not achieved clinically significant weight loss with lifestyle modifications alone.
Approaches and tools
Obesity treatment is analogous to the treatment of other chronic medical conditions such as hypertension or diabetes. First, a goal is set; for weight management, initial weight loss of 5% to 10% is reasonable, as this can lead to important improvements in health and function and can reduce risk factors.2 Then, a multimodal treatment strategy starts with lifestyle modifications, including dietary changes, behaviour changes, and regular physical activity. Finally, as in the case of target blood pressure or glycemic control that has not been achieved by lifestyle changes, the addition of pharmacotherapy is considered. The treatment of excess weight and obesity can and should be looked at in a similar manner.
Not all patients will achieve clinically significant weight loss with lifestyle modification alone. Pharmacotherapy used as an adjunct to lifestyle counseling has been shown to augment weight loss in primary care,3 and PCPs should be able to offer pharmacotherapy to selected patients and feel comfortable doing so.
Pharmacotherapy for weight management is generally approved for individuals with a body mass index (BMI) of 30 kg/m2 or greater or for those with BMIs between 27 and 30 kg/m2 who also have a weight-related comorbidity such as type 2 diabetes mellitus, obstructive sleep apnea, hypertension, or hypercholesterolemia.2
Currently in Canada, 2 medications are approved by Health Canada to support weight loss: orlistat and, recently, liraglutide. Available over the counter in the United States and approved in Canada since 1999, orlistat is a pancreatic and gastric lipase inhibitor taken with meals that inhibits dietary fat absorption by up to 30%. The actions of orlistat are localized to the gastrointestinal tract, and potential side effects are mainly gastrointestinal and can include oily stool, fecal urgency, and fecal leakage.4 When used with lifestyle modification, orlistat has been found to result in additional weight loss of approximately 3 kg or 3% of body weight.2
In 2015, after publication of the CTFPHC guidelines, liraglutide, a glucagonlike peptide 1 analog, was approved in Canada for weight management.5 Glucagonlike peptide 1 regulates appetite and food intake. For weight loss, 3 mg of liraglutide is given subcutaneously daily; the most common adverse effects are nausea, vomiting, and diarrhea.4 Adding liraglutide to lifestyle modifications has been shown to result in an additional 5.6 kg of weight loss or 8% of body weight compared with lifestyle modifications alone, as well as improvement in obesity-related risk factors.6 An advantage of liraglutide is that many PCPs are already familiar with it, as 1.2- and 1.8-mg doses have been available in Canada for diabetes management since 2010.4
Unlike in the CTFPHC guidelines, the use of pharmacotherapy to aid weight loss in overweight and obese patients is fully supported by the Endocrine Society’s 2015 clinical practice guidelines.2
To assist in clinical practice, a 2015 Lancet series suggests a multi-step algorithm to simplify screening and treatment of patients who are overweight or obese and their associated complications. The initial approach is to offer lifestyle modification programs, which include reducing caloric intake by 500 to 1000 kcal per day, moderate physical activity on most days of the week, and cognitive behavioral therapy. If weight loss of an average of 0.5 kg per week at 3 to 6 months has not been achieved, pharmacotherapy is recommended for those with a BMI of 30 kg/m2 or greater and those with a BMI of 27 kg/m2 or greater who also have risk factors.7
The consequences of excess body weight are well known: increased morbidity associated with hypertension, cardiovascular disease, diabetes, stroke, osteoarthritis, obstructive sleep apnea, and certain types of cancer.8 These consequences affect a large proportion of primary care patients; as of 2013, 62% of Canadian adults (aged 18 to 79 years) were estimated to be overweight or obese, based on a calculated BMI of 25 kg/m2 or greater.9
The CTFPHC guidelines deemphasize the role of PCPs in the prevention and treatment of obesity. However, access to bariatric centres is limited in many areas. Given the high proportion of individuals in Canada who are overweight or obese, and the potential health benefits to patients of losing even 5% to 10% of their body weight, PCPs should feel comfortable helping patients achieve weight loss by not only recommending lifestyle modifications, but also suggesting pharmacotherapy when appropriate. Pharmacotherapy for weight management is an important tool, and side effects of currently approved therapy are mainly gastrointestinal in nature.
Obesity is a chronic disease; building supports, improving available treatments, and implementing best practices will take time. Providing pharmacotherapy for weight management is something family physicians can easily do now to help patients individually, as well as to help fight the obesity epidemic.
CLOSING ARGUMENTS — YES
Laura Bourns MD CCFP Judy Shiau MD FRCPC Dip ABOM
Obesity is a chronic disease and, just like other chronic diseases (eg, diabetes, hypertension), after failed lifestyle changes, patients require pharmacotherapy for treatment.
Nearly two-thirds of the Canadian population is overweight or obese. As primary care providers (PCPs) are the front line of care, they must be prepared and armed with tools such as medications for weight management.
Practical algorithms and decision aids exist to assist PCPs in treating patients who are obese or overweight.
Liraglutide (3.0 mg) and orlistat are currently available in Canada. Both have, at most, potential gastrointestinal side effects. Orlistat has been available since 1999 and liraglutide in 1.2- and 1.8-mg doses has been available in Canada since 2010. Therefore, PCPs already have familiarity with these drugs and should be able to administer them as needed.
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