Adults on GLP-1s who lost weight during their first year on the medications are likely to maintain that loss through the second year of use, according to two new Cosmos studies.

That finding was true for those with diabetes and without.

“We did observe that patients without diabetes had higher rates of maintaining that weight loss,” said Kersten Bartelt, RN, a researcher at Epic Research and a coauthor on both studies. And those on tirzepatide had lower rates of weight regain that those on semaglutide, the two medications studied.

Bottom line? Continued use of GLP-1s means continued weight loss benefit or maintenance, Bartelt said.

The studies were published on August 12 and August 13 on the Epic Research website.

Studies in Detail

At the 2-year mark, those without diabetes were more likely to maintain their weight loss than those with diabetes.

While 53.1% of patients on semaglutide and 52.9% of patients on tirzepatide without diabetes maintained their weight at the 2-year mark, 37.7% of patients on semaglutide and 47.3% of patients on tirzepatide with diabetes maintained their weight loss at the 2-year mark.

The data come from Cosmos, a dataset created in collaboration with a community of Epic health systems representing more than 310 million patient records from 2100 hospitals and more than 49,000 clinics from all 50 states and elsewhere. Each health system owns the data and can choose to opt in to Cosmos, said Caleb Cox, director of research at Epic.

The research on patients with diabetes looked at 38,621 adults who started a GLP-1 medication, stayed on it continuously for at least a year, and lost at least 5 lb that first year. Researchers tracked weight monthly to determine if the first-year loss was retained, regained, or extended.

At 2 years, 26.9% of semaglutide users and 14.2% of tirzepatide users had regained at least a quarter of their first-year loss.

The study on those without diabetes looked at 25,213 adults who started a GLP-1 medication, stayed on it continuously for at least a year and lost at least 5 lb that first year. Weight was tracked monthly, evaluating if the first-year loss was retained, regained, or extended.

At 2 years, 14.9% of semaglutide users and 8% of tirzepatide users regained at least a quarter of the loss from the first year.

At the 2-year mark, more than 30% of both groups continued to lose weight.

Full return to baseline weight was uncommon, with 1%-1.5% of those without diabetes and 1.6%-5% of those with diabetes doing so.

“We decided to look at this after hearing anecdotal reports [from patients] saying, ‘I’m gaining it back’. Just because medications work initially doesn’t mean they will work long term,” Cox told Medscape Medical News.

The results will enable clinicians to tailor the use of these medications to individuals, rather than following blanket recommendations, Bartelt said. Both studies were conducted by two teams, working independently, with a clinician and research scientist on each team. The teams came to similar conclusions.

While tirzepatide was found more effective on some measures, other considerations must be weighed, such as costs and side effects, Cox said.

Clinician’s Take

The key finding? “Patients only maintain the degree of weight loss if they continue GLP-1s,” said Caroline Apovian, MD, co-director of the Center for Weight Management and Wellness, Brigham and Women’s Hospital, Boston. She reviewed the research study on those with diabetes for Medscape Medical News.

“Patients who try to come off regain the weight and then realize this and accept the idea,” she said. Most of her patients accept her original advice to stay on the medications when they have been effective.

Sometimes, it’s not the patient who decides to discontinue, she said, but a change in health plan coverage that makes it impossible for them to continue the medications. Currently, she is caring for a patient who weighed 725 lb with a BMI of 70 before losing 100 lb on Zepbound but then lost healthcare coverage for the medication.

As expected, he is gaining weight back — and needs to maintain the loss so he can undergo bariatric surgery. “We are now trying to get him samples of Zepbound to get him to surgery,” Apovian said.

No sources had any disclosures.

The studies had no external funding.