Observational study finds stopping GLP-1 therapy increases cardiovascular risk among veterans — Evidence Review

Stopping GLP-1 medications such as semaglutide or tirzepatide may rapidly diminish their heart-protective benefits in people with type 2 diabetes, according to a large study of U.S. veterans. Prior research has consistently shown that ongoing GLP-1 use lowers cardiovascular risk, and the new findings from Washington University School of Medicine extend this evidence by highlighting the risks of even short-term discontinuation.

• Meta-analyses and clinical trials have repeatedly found that continuous GLP-1 therapy reduces major cardiovascular events, stroke, and mortality in type 2 diabetes patients, supporting the current study's emphasis on the importance of ongoing treatment 1 2 3 4 5.
• The new study adds nuance by demonstrating that interrupting or ceasing GLP-1 therapy—even for as little as six months—can negate or reverse these protective effects, a dynamic that prior research had not directly addressed 1 2.
• Related studies focus mainly on the benefits of GLP-1 receptor agonists compared to placebo or other therapies, but have not systematically investigated outcomes following treatment discontinuation, making the present findings a notable extension of the existing evidence base 1 2 3 4 5.

Study Overview and Key Findings

Interest in GLP-1 receptor agonists has surged due to their proven benefits for both diabetes management and cardiovascular risk reduction. While much attention has focused on starting these medications, less is known about what happens if treatment is stopped. This is especially relevant given the high rates of discontinuation due to cost, side effects, or drug shortages. The present study addresses this gap by examining cardiovascular outcomes in a large cohort of U.S. veterans with type 2 diabetes who started, stopped, or interrupted GLP-1 therapy over a three-year period.

Property	Value
Organization	Washington University School of Medicine in St. Louis
Journal Name	BMJ Medicine
Authors	Ziyad Al-Aly, MD
Population	U.S. veterans with type 2 diabetes
Sample Size	n=333,687
Methods	Observational Study
Outcome	Major adverse cardiovascular events, including heart attack and stroke
Results	Stopping GLP-1 therapy increased cardiovascular risk by up to 22%.

Literature Review: Related Studies

To contextualize these findings, we searched the Consensus database, which includes over 200 million research papers, using specific queries to identify relevant literature. The following search queries were used:

1. Ozempic discontinuation cardiovascular risk
2. GLP-1 therapy cessation heart attack stroke
3. stopping diabetes medication cardiovascular effects

Summary Table: Key Topics and Findings

Topic	Key Findings
What are the cardiovascular benefits of continuous GLP-1 therapy in type 2 diabetes?	- GLP-1 receptor agonists consistently reduce major adverse cardiovascular events (MACE), cardiovascular mortality, all-cause mortality, and stroke in patients with type 2 diabetes 1 2 3 4 5 6 8. - These benefits are seen across various GLP-1 agents, with some variability in effect size for individual drugs 3 5 8.
Do discontinuation or interruptions in GLP-1 therapy reverse or diminish these benefits?	- While most meta-analyses focus on continuous therapy, the new study provides evidence that stopping or interrupting GLP-1 therapy can quickly erode cardiovascular protection, with risk returning to or exceeding that of alternative therapies after discontinuation [Current Study]. - Prior research had not directly addressed outcomes after cessation 1 2.
How do GLP-1 receptor agonists compare to other diabetes medications for heart outcomes?	- Compared to sulfonylureas and placebo, GLP-1 receptor agonists reduce the risk of cardiovascular events without increasing key safety risks such as severe hypoglycemia, pancreatitis, or pancreatic cancer 1 2 3 5. - SGLT2 inhibitors also reduce cardiovascular events, but have distinct safety profiles and mechanisms 7 10.
Are the cardiovascular effects of GLP-1 therapy durable, and what happens after stopping?	- Most studies focus on the period of active treatment, demonstrating gradual accumulation of cardiovascular benefit with sustained therapy 1 2 3 4 6 8. - The current study uniquely demonstrates that cardiovascular protection may dissipate rapidly following cessation, with only partial recovery upon resuming treatment [Current Study].

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What are the cardiovascular benefits of continuous GLP-1 therapy in type 2 diabetes?

Multiple large meta-analyses and randomized controlled trials have established that GLP-1 receptor agonists provide significant cardiovascular protection for people with type 2 diabetes. These benefits include reduced incidence of heart attack, stroke, cardiovascular mortality, and all-cause mortality, and are generally consistent across different drugs within the class.

• Meta-analyses report a 10-14% reduction in major adverse cardiovascular events (MACE) with GLP-1 therapy versus placebo 1 2 3 5.
• Benefits extend to both patients with and without established cardiovascular disease 5.
• Individual GLP-1 agents may vary somewhat in efficacy, but the class effect is robust 3 5 8.
• These therapies also reduce kidney disease progression without significant increases in adverse safety outcomes 1 2 4.

Do discontinuation or interruptions in GLP-1 therapy reverse or diminish these benefits?

While prior literature has established the benefits of continuous GLP-1 therapy, there has been limited investigation into what occurs after discontinuation. The current study is notable for showing that even brief interruptions (as short as six months) can substantially increase cardiovascular risk, effectively negating the accrued benefit.

• Previous meta-analyses and trials did not systematically study outcomes after stopping GLP-1 therapy 1 2.
• The present study fills this gap, documenting a 22% higher risk of heart attack, stroke, or death after two years off therapy, compared to continued use [Current Study].
• Temporary interruptions also reduce benefit, and resuming therapy only partially restores lost protection [Current Study].
• These findings highlight a potential "metabolic whiplash" effect upon stopping GLP-1s, which has not been previously quantified [Current Study].

How do GLP-1 receptor agonists compare to other diabetes medications for heart outcomes?

GLP-1 receptor agonists outperform sulfonylureas and placebo in reducing major cardiovascular events and mortality, with a favorable safety profile. SGLT2 inhibitors also lower cardiovascular risk but pose different risks, such as increased amputation rates in some studies.

• GLP-1 receptor agonists reduce major cardiovascular events, stroke, and heart failure hospitalization more than sulfonylureas and without increasing hypoglycemia or pancreatitis risk 1 2 3 5.
• SGLT2 inhibitors like canagliflozin and ertugliflozin provide cardiovascular and renal benefits but have unique safety considerations, including risk of amputation with canagliflozin 7 9 10.
• The new study directly compares GLP-1s to sulfonylureas, showing superior continuous benefit with GLP-1s and diminishing protection after cessation [Current Study].
• Both GLP-1 and SGLT2 inhibitors are now considered for cardiovascular risk reduction in diabetes guidelines, but their benefits and risks differ 1 2 5 7.

Are the cardiovascular effects of GLP-1 therapy durable, and what happens after stopping?

Prior studies document that the cardiovascular benefits of GLP-1 therapy build up gradually over time with ongoing use. The current study uniquely addresses the durability of these effects, finding that they may be lost quickly if treatment is interrupted or stopped.

• Sustained GLP-1 therapy is associated with a cumulative reduction in cardiovascular events over years 1 2 3 4 6 8.
• The present study is the first large-scale analysis to show that these benefits can disappear rapidly—within months of stopping therapy [Current Study].
• Restarting GLP-1 therapy only partially restores lost cardiovascular protection, suggesting some effects of interruption may be irreversible [Current Study].
• These findings imply that continuous adherence is critical for maintaining cardiovascular benefit, a message that had not been previously emphasized [Current Study].

Future Research Questions

Further research is warranted to clarify the mechanisms underlying the rapid loss of cardiovascular protection after GLP-1 discontinuation, to explore whether these effects are generalizable beyond the veteran population, and to optimize long-term management strategies for individuals with type 2 diabetes.

Research Question	Relevance
What mechanisms drive the rapid loss of cardiovascular benefits after GLP-1 therapy discontinuation?	Understanding the biological or metabolic processes underlying this rapid reversal could inform strategies to mitigate risk during treatment gaps [Current Study, 1,2].
Are the effects of GLP-1 discontinuation on cardiovascular risk similar in non-veteran and international populations?	The current study focuses on U.S. veterans; broader studies could test the generalizability of findings across diverse populations and healthcare systems [Current Study, 1,2].
Can adjunctive therapies reduce the risk associated with GLP-1 therapy interruption?	Exploring whether other medications (e.g., SGLT2 inhibitors, statins) can offset the increased cardiovascular risk during GLP-1 treatment gaps may improve patient outcomes 7 10.
What are the long-term cardiovascular and metabolic outcomes of multiple cycles of starting and stopping GLP-1 therapy?	Many patients cycle on and off GLP-1 drugs; understanding cumulative effects of repeated interruptions is crucial for real-world management [Current Study].
How do patient characteristics (e.g., duration of diabetes, baseline cardiovascular risk) influence the impact of GLP-1 discontinuation?	Personalizing therapy duration and monitoring may depend on which subgroups are most vulnerable to harm from stopping treatment 1 2 5.

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This comprehensive analysis highlights the importance of continuous GLP-1 therapy for sustained cardiovascular protection in type 2 diabetes, reveals novel risks associated with treatment interruptions, and underscores the need for further research to optimize long-term diabetes care.