Precarious Prescriptions: Lab Testing and Coverage for GLP-1 Drugs

           

In recent years, glucagon-like peptide-1 (GLP-1) receptor agonists have gone from obscure type 2 diabetes drugs to headline news for weight loss, polycystic ovary syndrome, and more. But these drugs come at a cost; with a significantly higher price tag than other treatments for cardiometabolic disorders, many people face difficulties obtaining coverage or paying out of pocket for their medication. 

Studies indicate that fewer than 10 percent of eligible patients with type 2 diabetes are prescribed a GLP-1 drug; conversely, 7.2 percent of patients who did receive a prescription were ineligible under their health insurance providers’ stated criteria. In many cases, those patients’ lab values—in particular, hemoglobin A1c (HbA1c)—don’t reflect the uncontrolled diabetes required to justify coverage for GLP-1 receptor agonist treatment.

To find out more about the discrepancy between GLP-1 drug eligibility and prescription, we spoke to Julie Schulz, MD, MPH, vice president of product at lab insights company Avalon Health.

What are GLP-1 receptor agonists?

These drugs mimic the function of GLP-1, a hormone naturally secreted in the small intestine that mediates metabolic functions like insulin release, glucagon blockage, and sensations of satiety. In type 2 diabetes, GLP-1 receptor agonists can stimulate the pancreas to release more insulin and slow digestion to mitigate blood sugar spikes and drops. When used for weight loss, the resulting slower digestion and increased satiety reduce patients’ appetites and feelings of hunger. 

What inspired you to examine the link between lab values and GLP-1 receptor agonist prescription?

GLP-1 analogs are very popular, but although most insurers cover them as a treatment for uncontrolled diabetes, very few commercial health plans cover them for weight loss. We wanted to see whether patients who had been prescribed these drugs for diabetes actually had uncontrolled diabetes—and, ultimately, we found that many did not have confirmatory HbA1c values. It’s possible that some physicians are prescribing these drugs for weight loss, but trying to have patients’ health insurance cover the treatment. Many physicians, when surveyed, say that they might lie on a claim to obtain tests or treatments they believe their patients need.

Insurance companies have had their pharmacy budgets blown up by GLP-1 drugs and other specialty medications. They need to control that spending by leveraging lab values to ensure that patients meet coverage criteria. They could also use lab values—not just HbA1c, but also lipids, glucose, liver function, and kidney function—to identify patients who are at high risk of cardiometabolic conditions and who might therefore benefit from GLP-1 drugs.

In your opinion, what lab tests should be used to help determine whether or not to prescribe GLP-1 receptor agonists?

Obesity affects over 40 percent of Americans—but only about 6 percent of the US population is on a GLP-1 drug of some kind. Even if not every person with obesity should be on GLP-1 drugs, there’s still a huge gap.

Other than HbA1c, markers of cardiovascular disease might include lipids (total cholesterol, high- and low-density lipoproteins, and triglycerides) and more niche labs like lipoprotein(a), a marker present in about 20 percent of the population that indicates a genetic predisposition toward cardiovascular disease.

Many patients with cardiometabolic syndrome develop metabolic dysfunction-associated steatohepatitis (fatty liver disease). Not only that, but about 90 percent of patients with chronic kidney disease go undiagnosed until the later stages of disease because the symptoms are so common and so variable. As a result, liver and kidney function testing can be crucial for spotting cardiometabolic dysfunction early.

With more research emerging on the value of GLP-1 receptor agonists, what testing and prescribing trends do you foresee?

SGLT2 inhibitors, a related medication, were initially approved for diabetes, but then subsequently had indications added for heart failure and chronic kidney disease. I think GLP-1 drugs are likely to follow a similar path. Currently, they’re only indicated for diabetes, weight loss, and the prevention of major adverse cardiac events in patients who have atherosclerotic cardiovascular disease—but the research shows significant benefit in chronic kidney disease, so I think that’s probably on the horizon.

There’s a lot of research into heart failure and, more recently, the links between cardiometabolic health, Alzheimer’s disease, and dementia. It’s an exciting time to be in medicine because, even though we don’t fully understand these drugs’ mechanisms of action, we see pretty significant and compelling benefit for their use in diseases that are otherwise major killers. It really drives home the interconnectedness of these metabolic systems.

How can clinical laboratory professionals promote appropriate testing for treatment selection?

I mentioned chronic kidney disease; often, a patient’s lab values might suggest worsening kidney function, but doctors don’t see it because it’s all part of a larger panel. Lab professionals can help make sure doctors see and understand the values that are out of range or trending downward. They can also provide education and support to help providers learn to make more efficient and effective test ordering decisions.

I think that taking these routine lab values and putting them into risk calculators that consider the full health picture can help us understand a patient’s risk of major adverse cardiac events. The more we can tie disparate data points together, the better we can quantify risk—and labs are well placed to do this because these tests are complicated and many physicians are overloaded. By calculating each patient’s long-term risk and alerting their primary healthcare providers when necessary, labs can help those providers make better decisions at the point of care.

Labs can also help providers and patients track their results and see the impact of GLP-1 receptor agonist treatment—not just in improving individual lab values, but also in reducing their overall risk of a major adverse event. Showing the decrease in that calculated risk as patients’ lab results improve with treatment can reinforce GLP-1 drugs’ positive health impact and demonstrate their value in preventive care.

What does the future look like for GLP-1 receptor agonists?

I think we’ll see expanded indications for GLP-1 drugs in 2025, alongside further research that supports other potential uses. I also think we’ll see an explosion of similar drugs on the market. There’s a healthy pipeline for new GLP-1 drugs that will likely be more effective, have fewer side effects, and potentially be indicated for more conditions.

I don’t think there will be any relief in pharmacy budgets anytime soon. We have to consider GLP-1 drugs’ longer-term societal impact because they have the potential to be cost-effective years or decades down the line. That may require some form of government incentive or intervention to ensure coverage for these drugs because insurers don’t typically think that far into the future—but I think that, with the right motivation, these drugs could make a significant difference to our health and to society as a whole.