Regarding weight loss medication use, appropriate treatment plans frequently depend on the severity of obesity and the presence of concurrent chronic health conditions. Clinical studies support a plan to include a comprehensive approach that may involve lifestyle changes, pharmacologic therapy, and in some cases, bariatric surgery. 

However, any treatment plan should stay flexible for individual needs and provide a base for ongoing weight management, said Jonathan Purnell, MD, professor of medicine, Division of Cardiovascular Medicine, Oregon Health & Science University School of Medicine in Portland. “Regular monitoring and support help maintain weight loss and avoid regain,” he told Medscape Medical News. 

As a primary care provider, you understand that obesity is defined as excess body fat, most often assessed using body mass index (BMI), which estimates body fat based on a patient’s height and weight. BMI serves as a screening tool rather than a direct measure of adiposity, said Victoria J. Grille, MD, bariatric and general surgeon with expertise in weight loss management, Hackensack Meridian Jersey Shore University Medical Center, Neptune City, New Jersey. 

Weight categories are generally classified as follows: 

• Overweight: BMI 25.0-29.9
• Class I obesity: BMI 30.0-34.9
• Class II obesity: BMI 35.0-39.9
• Class III obesity (severe/morbid obesity): BMI ≥40

These classifications are determined primarily by BMI, but clinical decision-making also considers the presence of obesity-related comorbidities (such as hypertension, type 2 diabetes, obstructive sleep apnea, and cardiovascular disease) as well as overall patient risk profile and functional status, Grille said.

“BMI categories are clinically useful because they help guide treatment intensity and determine eligibility for both pharmacologic and surgical weight management options,” she said.

Overall, these classifications provide a structured framework to stratify risk, guide treatment selection, and standardize care while still allowing for individualized, patient-centered decision-making based on comorbidities, functional status, and treatment response, Grille told Medscape Medical News.

Factors That May Shift Treatment Directives 

Obesity treatment in primary care should be customized to each patient's needs and preferences. These are some key points and principles to know.

• The American Diabetes Association recommends losing 3%-7% of body weight through lifestyle changes, with higher targets for certain health benefits.
• Patient-centric guidelines recommend using nonjudgmental language when discussing weight loss strategies in clinical care settings.
• Clinical management success may depend on monitoring and maintaining patient motivation.

Grille recommended how patients should be closely monitored while on these GLP-1 medications. 

“An initial follow-up is typically scheduled approximately 2 months after initiation to assess tolerability, response, and early side effects. Thereafter, follow-up is generally conducted every 3 months until the patient is on a stable dose,” she said. “Once a stable and well-tolerated dose has been maintained for at least 3 months, visit frequency may be extended to every 6 months, assuming ongoing clinical stability.”

Clinical Considerations Across Different Degrees of Obesity

Several clinical indicators may warrant your decision to initiate GLP-1 therapy. 

The first is a patient’s BMI. 

“When BMIs are greater than 30 kg/m², GLP-1 and GLP-1/GIP RAs are a good choice to combine with lifestyle because of available obesity medications, they can offer maximal medical weight loss effectiveness,” said Purnell at Oregon Health & Science University School of Medicine.

Of note, he said if a patient is of European heritage, a BMI ≥ 27 kg/m² (BMI of 25 kg/m² or higher if of Asian descent) with an obesity complication qualifies a patient for a discussion about initiating an obesity medication in addition to lifestyle.

“Using evidence from recent trials and FDA approval status, the type and severity of obesity complication can help guide which GLP-1 or GLP-1 RA might be a first choice,” Purnell said.

For example, Purnell said that for patients with a BMI of 27 and higher who have had a heart attack or stroke, semaglutide 2.4 has been shown to reduce cardiac events and total mortality. Clinical data has shown that both semaglutide 2.4 and tirzepatide have reduced liver fat and improved fibrosis in more advanced liver disease. 

“The reality is, though, that individual patients respond differently to individual medications, both in terms of effectiveness and side effects,” he said. “A provider might start with one but switch to another depending on response.”

In addition, Purnell said that at higher BMI levels, GLP-1 and GLP-1/GIP RAs will need to be combined with other obesity medications to achieve weights as close to the healthy range as possible. 

“This is based on how we manage other chronic diseases of greater severity (combination therapy), although we are awaiting outcomes studies to support this advice,” he said. 

Purnell is an advisory board member for Novo Nordisk, Boehringer-Ingelheim, and Zealand Pharmaceuticals. He is also a clinical trialist for Novartis and Amgen. Grille reported no disclosures.