What it means for clinicians
The upshot of all of these cardiovascular outcome trial results that came out over the past 3 years has been a new appreciation of how antihyperglycemic drugs can have cardiovascular and renal benefits that transcend their effects on glycemia. The evidence has put the SGLT2 inhibitors and GLP-1 RAs on track to challenge, and potentially displace, metformin as the top drug to prescribe for patients with T2DM.
Clinicians should realize that they should prescribe SGLT2 inhibitors and selected GLP-1 RAs “as early as metformin in patients with established ASCVD,” said Dr. Verma. “For patients with recalcitrant atherosclerotic disease and a history of MI and ischemia, I’d primarily treat with a GLP-1 RA. In a patient with left ventricular dysfunction or evidence of heart failure, I’d use an SGLT2 inhibitor. But it’s not a fight between these two. You could treat a patients with type 2 diabetes with both classes,” although the practicality of this approach is limited by the high cost of these drugs.
The SGLT2 inhibitors “should now be considered as first-line therapy after metformin in most people with type 2 diabetes, irrespective of whether or not they have established atherosclerotic vascular disease, chronic kidney disease, or heart failure,” he and his associates wrote in their recent commentary.
“What I struggle with the most is how we prioritize and individualize secondary-prevention therapies based on risk for ischemia and heart failure. Some therapies [the SGLT2 inhibitors] are predominantly for heart failure prevention, and some [the GLP-1 RAs] are primarily for ischemia. How do we choose when a patient cannot afford to take both? Does a combination of a SGLT2 inhibitor and a GLP-1 RA offer the greatest CVD benefit? We need to test this in a trial. And will metformin be displaced as first-line treatment?” Dr. Verma asked.
“The day will probably come when, for maximal protection, you treat with both classes. But right now we’re forced to choose because of the cost,” said, professor of cardiology at the University of Glasgow, in a talk during the meeting.
As to specifically which SGLT2 inhibitor to prescribe, “they all look pretty much the same” in the newly published meta-analysis, Dr. McMurray said, although he noted that safety differences among agents in the class remain possible.
“For patients similar to those studied in the three SGLT2 inhibitor trials, clinicians should use one of these drugs to reduce the risk for incident heart failure, irrespective of their effect on MACE,” said Dr. Butler. Reducing the risk for incident heart failure and of progressive renal dysfunction are two new goals for antihyperglycemic therapy that now overlay the long-standing goals of controlling glycemia and reducing cardiovascular disease risk and the more recent goals of cutting cardiovascular disease mortality and cutting the risk for a MACE event.
A current limitation for practice is that the none of the three drug companies that market the tested SGLT2 inhibitor drugs has sought regulatory approval for an indication of reducing the risk for heart failure hospitalization. Despite that, “these drugs should be used for renal protection and reducing heart failure hospitalizations,” Dr. Butler said. “We need to start thinking about this and not get lost thinking about only their MACE effect because, when you focus on MACE, there is a competition between the SGLT2 inhibitors and the GLP-1 RA. If we think of GLP-1 RAs as drugs to prevent MACE, and SGLT2 inhibitors as drugs that primarily prevent heart failure and renal dysfunction, then there is no competition. Perhaps combined treatment is where we need to go,” he said in an interview.
But the enthusiasm that experts like Dr. Butler, Dr. McMurray, and Dr. Verma have for wider use of both classes of drugs in appropriate patients is not necessarily matched right now among many community physicians. Cardiologist, is an example of the clinicians who appreciate the growing evidence that supports wider use of these antihyperglycemic drugs but remain uneasy about applying this evidence in their practice.
Dr. Becker, associate director of the Preventive and Integrative Heart Health Program of the Temple Heart and Vascular Institute in Philadelphia, writes a column for the Philadelphia Inquirer on medical care. In a December 2018, he said “like most cardiologists, I ‘don’t do diabetes’ – because it’s not my expertise. The new drugs, however, mean I need to learn more” about treating these patients. “The problem: There are so many of these medications that they present a bewildering choice for patients and doctors.”
Dr. Becker cited several barriers he sees for himself and his nonendocrinologist colleagues to prescribe these drugs – and for patients to take them: