Two groups of drugs for type 2 diabetes — SGLT2 inhibitors and GLP-1 receptor agonists — improve cardiovascular outcomes both in people who take insulin and in those who don’t, according to a new analysis published in the Journal of the Endocrine Society.
Researchers looked at recent clinical trials of new diabetes drugs, published between 2010 and 2019. Out of 12 studies that looked at cardiovascular outcomes in people who took these drugs, eight provided outcomes separately for participants who took insulin and those who didn’t. The researchers were interested in comparing the rate of adverse cardiovascular events — like a heart attack or stroke — in people who took type 2 drugs without insulin, and in people who took them along with insulin.
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The eight studies in the analysis had a total of 82,904 participants, including 45,552 people who didn’t take insulin and 37,352 who took insulin at the beginning of the study. These large numbers give some weight to the outcomes the researchers observed, and all of the studies also included “robust adjudications of events” to ensure that cardiovascular outcomes were measured accurately. The researchers wanted to separate participants further based on diabetes severity and how long people had been taking insulin, but there wasn’t enough data available to do this.
Not surprisingly, the researchers found that overall, people who took insulin along with other diabetes drugs were more likely than those who didn’t take insulin to experience major cardiovascular events — 52% more likely. The most likely explanation for this finding is that people with type 2 tend to start taking insulin only when their diabetes is advanced enough that other treatments are no longer adequate to control blood glucose. Having diabetes for a longer period of time, and having diabetes that’s more difficult to control, are both linked to worse cardiovascular outcomes.
SGLT2 inhibitors and GLP-1 receptor agonists show cardiovascular benefits
But the effects of taking two particular groups of diabetes drugs — SGLT2 inhibitors (such as Farxiga, Invokana, Jardiance, and Steglatro) and GLP-1 receptor agonists (such as Adlyxin, Bydureon, Byetta, Ozempic, Tanzeum, Trulicity and Victoza) — were notable when it came to cardiovascular risk. Study participants who took these drugs showed a reduced risk of cardiovascular events compared with those who took a placebo (inactive substance), while people who took a DPP-4 inhibitor (such as Galvus, Januvia, Onglyza or Tradjenta) didn’t see any cardiovascular benefit compared with taking a placebo.
This cardiovascular benefit from SGLT2 inhibitors and GLP-1 receptor agonists was seen both in people who also took insulin and in those who didn’t, as noted in a Healio article — with a 15% lower risk for major cardiovascular events in those who didn’t take insulin, and a 7% lower risk in those who took insulin, compared with taking a placebo in each group. Since the cardiovascular benefit from these drugs was greater in people who didn’t take insulin, the researchers suggested that to get as much benefit as possible, people should start taking these drugs earlier in the course of their diabetes, before insulin becomes necessary.
“We believe that as [diabetes] progresses the benefit is attenuated, therefore it may be important to use these drugs early on in the disease before it progresses,” the researchers wrote. But “even in insulin-treated patients, there is still a cardiovascular benefit gained when a GLP-1 or an SGLT2 inhibitor is added to the treatment regimen.”
Want to learn more about protecting your heart? Read “Be Heart Smart: Know Your Numbers,” “Does Diabetes Hurt Your Heart?” “Fight Off Heart Disease With These Five Heart-Healthy Foods” and “Lower Your Risk of Heart Disease.”