Weight Management Treatments Might Make a Dent in Obesity Rates, But Only If Patients Start Using Them

Weight management treatments (WMT) like nutritional counseling, low-calorie meal replacement (MR), antiobesity medications (AOM), and bariatric surgery, all increase the possibility that patients with obesity will achieve 5% or greater weight loss; however, the population-level impact of these treatments is hampered by low utilization rates, according to findings published in JAMA Network Open.

Obesity rates are still on the rise, with estimates projecting that 50% of U.S. adults will have obesity by 2030. Recently, GLP1RAs, such as semaglutide and liraglutide, have arisen as potentially effective weight management tools. Unfortunately, the high cost of these agents and the necessity for lifelong use to prevent weight regain prevent them from being a universal weight management solution, study author Dina H. Griauzde, MD, MSc, of University of Michigan Medical School in Ann Arbor, Michigan, and colleagues explained.

To help fill this knowledge gap, Griauzde and colleagues conducted a retrospective cohort study designed to characterize weight status among patients with established primary care; describe WMT use; explore associations between WMT and weight trajectories; and estimate the level of WMT engagement necessary to trigger a population-level reduction in weight.

For their analysis, Griauzde et al pulled University of Michigan electronic health record (EHR) data for patients ages 18 years and older with two or more primary care visits 358 days or more apart in the preceding 3 years. Patients with obesity and WMT exposure were compared against matched controls. Assessed WMTs included receipt of nutrition counseling by a registered dietitian (RD), prescriptions for AOM, participation in a very low-calorie meal replacement (MR) program, and bariatric surgery. The study authors used a cross-sectional analysis to compare mean body mass index (BMI), obesity prevalence, and prospective WMT use (among patients with obesity); they also conducted a trajectory analysis to examine longitudinal weight status using thresholds of ±5% and 10% of baseline weight, with primary outcomes being 1-year probabilities of 5% or greater weight loss for each WMT.

They found that, "[a]mong 138,682 patients, prevalence of obesity increased from 39.2% in 2017 to 40.7% in 2019; WMT use among patients with obesity increased from 5.3% to 7.1% (difference: 1.7%; 95% CI, 1.3%-2.2%). In a multistate model (10,180 patients; 33 549 patient-years), the 1-year probability of 5% or greater weight loss without WMT exposure was 15.6% (95% CI, 14.3%-16.5%) at reference covariates. In contrast, the probability of 5% or greater weight loss was more likely with year-long exposures to any WMT (nutrition counseling: 23.1%; 95% CI, 21.3%-25.1%; MR: 54.6%; 95% CI, 46.5%-61.2%; AOM: 27.8%; 95% CI, 25.0%-30.5%; bariatric surgery: 93.0%; 95% CI, 89.7%-95.0%)."

Griauzde et al concluded that their findings "provide novel insight into weight management in primary care settings by characterizing the use and effectiveness of WMT, including nutrition counseling with a dietitian, very low-calorie MR, AOM, and bariatric surgery. The overall rate of WMT utilization increased during the 2-year observation period but remained low at 7.1% in 2019. Without WMT exposure, the 1-year probability of achieving 5% or greater weight loss for a reference control was 15.6%. In our study, the annual probability of 5% or greater weight loss was estimated to increase with year-long exposure to any WMT, ranging from 23.1% for nutrition counseling to 93.0% for bariatric surgery. Additionally, WMT were associated with reduced probability of weight gain. These estimates reflect idealized circumstances, as most patients in real-world settings do not remain continuously engaged in WMT for 1 year. Efforts to help patients with obesity achieve and maintain 5% or greater weight loss should focus on increasing initial uptake and sustaining engagement in WMT.

Previously, they added, little was known about to what extent WMTs affected population-level weight loss.

"Among our cohort of patients with obesity, the average 1-year probability of achieving 5% or greater weight loss was 17.6%, with less than 1% associated with exposure to the WMT examined. This may reflect weight-loss efforts outside the health system, as approximately 60% of U.S. adults with obesity attempted to lose weight in the prior year. Despite the low fraction of 5% or greater weight loss associated with WMT, we found a 2-fold proportional increase in WMT use would be sufficient to make the probability of 5% or greater weight loss more likely than 5% or greater weight gain," they wrote.

Griauzde and colleagues also noted that, while they included GLP1RAs in their analysis, the study period predated the FDA’s approval of semaglutide (2.4 mg) for weight management.

"Future work should explore the potential for semaglutide 2.4 mg and other medications with substantial weight loss effectiveness to reduce weight at the population level," they argued. "Additionally, given their potential weight-loss effectiveness and lower cost, future work should explore strategies to enhance patient-centered use of all WMT."

Study limitations included use of EHR data from a single academic health system; weight data and WMT exposures were extracted from the EHR and may be subject to measurement error, and there was no information on WMT adherence; only WMT exposures delivered through the health system were captured; since this was a retrospective, observational analysis, the estimates of WMT efficacy may be biased by treatment selection effects; and the study occurred before FDA approval of semaglutide for weight management, and thus the findings may underestimate current use and efficacy of AOM.

The study was funded by grants from NIH and National Institute of Diabetes and Digestive Kidney Diseases, the Michigan Center for Diabetes Translational Research, the Michigan Nutrition Obesity Research Center, MCDTR, and the Elizabeth Weiser Caswell Diabetes Institute at the University of Michigan.

Study coauthor Lee reported receiving personal fees from Tandem Diabetes Care, Goodrx, and Sanofi Digital Advisory Board outside the submitted work. Coauthor Richardson reported receiving grants from Blue Cross Blue Shield Michigan, Nielson Foundation, Annals of Family Medicine, and Duke Clinical Research Institute with funding by Boehringer Ingelheim Pharmaceuticals and Lilly USA outside the submitted work; serving as editor of the Annals of Family Medicine; and being a committee member for the American Diabetes Association.

Griauzde DH, et al "Weight loss treatment and longitudinal weight change among primary care patients with obesity" JAMA Netw Open 2024; DOI: 10.1001/jamanetworkopen.2023.56183.