Feb 22, 2021
This week, join author Chintan Dave and Associate Editor Naveed Sattar as they discuss the risk of cardiovascular outcomes in Type 2 Diabetes patients following the addition of SGLT2 inhibitors versus sulfonylureas to baseline GLP-IRA therapy.
TRANSCRIPT BELOW:
Dr. Carolyn Lam:
Welcome to Circulation on the Run, your weekly podcast, summary, and backstage pass to the journal and its editors. We're your co-hosts, I'm Dr. Carolyn Lam, Associate Editor from the National Heart Center and Duke National University of Singapore.
Dr. Greg Hundley:
And I'm Dr. Greg Hundley, Associate Editor, director of the Pauley Heart Center at VCU Health in Richmond, Virginia.
Dr. Carolyn Lam:
Greg, I love today's featured paper. It's a question everybody's asking. It's about cardiovascular outcomes, potential benefits, following the addition of SGLT2T2 inhibitors versus sulfonylureas to baseline GLP-1 receptor agonist therapy. Now, okay, I'm going to keep you waiting because that was just a hook. We got to get to us summaries first. And I'm going to start. The first original paper I want to describe is an analysis of myocardial infarction from the ischemia trial. And it looks at the impact of different definitions on the incidents, prognosis and treatment comparisons.
Dr. Carolyn Lam:
Because I know you're going to ask, I'm going to tell us a little bit about ischemia. So in an ischemia and initial invasive strategy did not significantly reduce rates of cardiovascular events or all-cause mortality compared with a conservative strategy in patients with stable ischemic, heart disease, and moderate to severe myocardial ischemia. The most frequent component of the composite cardiovascular end points was myocardial infarction. So in the current report from Dr. Chaitman and colleagues from St. Louis University school of medicine, the aim was to compare treatment effects on the primary and major secondary competent end points in the ischemia trial using the pre-specified primary and secondary MI definitions.
Dr. Greg Hundley:
So Carolyn, what were those two EBI definitions, the primary and secondary?
Dr. Carolyn Lam:
Right. Now, I'm going to try to simplify this. So, for procedural MI, the primary MI definition use CK-MB as the preferred biomarker, whereas the secondary definition used cardiac troponin.
Dr. Greg Hundley:
Great, Carolyn. So what did they find?
Dr. Carolyn Lam:
So procedural MI definition had an important impact on event frequency and subsequent prognosis. When the pre-specified secondary MI definition was applied, the conservative strategy had a significantly lower composite event rate for the primary and major secondary trial end points, due to an increased number of procedural MIs in the invasive strategy. Furthermore, spontaneous Type One MI events associated with increased risk of cardiovascular death were reduced with an invasive strategy, which is either PCI or CABG.
Dr. Greg Hundley:
Nice, Carolyn. Well, my first paper actually is a favorite topic of yours, HFpEF. And it really involves the central command and the regulation of exercise rate response. It comes to us from Dr. Ben Levine and colleagues at the University of Texas Southwestern Medical Center in Dallas.
Dr. Carolyn Lam:
Yay.
Dr. Greg Hundley:
All right, Carolyn. So chronotropic incompetence is common in HFpEF. And it's linked to impaired aerobic capacity. Whether upstream, autonomic signaling pathways are responsible for raising exercise heart rate are impaired in patients with HFpEF, That's really unknown.
Dr. Carolyn Lam:
Yep. It is something that we wonder. And so what did Dr. Levine find?
Dr. Greg Hundley:
Thanks Carolyn. So the central command, so vaguely mediated and the metabo-barrow receptor function, which is sympathetically mediated in patients with HFpEF, We're not different from healthy senior controls, despite significantly lower peak whole body exercise, heart rates. So these results, Carolyn, demonstrate key reflex autonomic pathways, regulating exercise, heart rate responsiveness are actually intact in patients with HFpEF. Great new work from Dr. Ben Levine.
Dr. Carolyn Lam:
And I love the way you summarized that. Thank you, Greg. Well, my next paper is the first report implicating the cross priming function of dendritic cells in immunopathology after Type Two MI. And that includes inflammation, fibrosis and functional decline.
Dr. Greg Hundley:
So tell us a little bit more Carolyn about these dendritic cells?
Dr. Carolyn Lam:
Ah-ha so I was ready for that question. So after ischemic injury to the myocardium, dendritic cells respond to cardiomyocyte necrosis present the cardiac antigen to T-cells and potentially initiate a persistent auto-immune response against the heart. So cross priming dendritic cells may have the ability to activate both CD4-positive helper and CD8-positive cytotoxic T-cells in response to necrotic cells. And may thus be crucial players in exacerbating auto-immunity targeting the heart.
Dr. Carolyn Lam:
So, in this study, authors led by Dr. Sattler from Imperial College, London, performed some elegant mouse experiments and showed that cross-priming dendritic cells were present in the heart and activate it after ischemic injury. Depletion of these dendritic cell cross priming function, inhibited accumulation, and activation of cytotoxic T-cells and stopped myocardial immunopathology and functional decline. So with cross-priming, these authors provided a targetable pathway to prevent activation of T-cells cyto-toxicity and persistent post Mia immunopathology exacerbating heart failure risk.
Dr. Greg Hundley:
Oh, beautiful. Carolyn, what a great description there. So my next paper comes to us from Dr. David Park from the New York University school of medicine. So Carolyn elevated intracardiac pressure due to heart failure, induces electrical and structural remodeling of the left atrium that begets atrial myopathy and arrhythmias. At present the underlying molecular pathways that drive atrial remodeling during cardiac pressure overload are poorly defined. So the purpose of this study for these investigators was to characterize the response of the ETV1 signaling axis in the left atrium during cardiac pressure overload in humans, as well as mouse models. And explore the role of ETV1 in atrial electrical and structural remodeling.
Dr. Carolyn Lam:
Ah, another study involving both animal and human models. Very important subject too. So what were the results?
Dr. Greg Hundley:
Well, Carolyn, evidence from both the Cleveland Clinic, Biobank Human Subjects Repository and the animal science experiments revealed that ETV1 is downregulated in the left atrium during cardiac pressure overload. Thereby contributing to both the electrical and the structural remodeling that we observe in the left atrium during cardiac pressure overload.
Dr. Carolyn Lam:
Nice. Well, let's quickly finish up with what's in the mailbag. We've got a research letter by Dr. Randi on the lack of evidence of AEs to expression and replicative infection by SARS-CoV-2 in human endothelial cells. There's another by Dr. Stokes on the association of cigarette and electronic cigarette use patterns with levels of inflammatory and oxidative stress biomarkers among US adults. And another research letter by Dr. Hemelsoet on screening for Fabry disease in male patients with arrhythmia requiring pacemaker or ICD.
Dr. Greg Hundley:
Thanks Carolyn. So I've got a paper it's a cardiovascular case series from Dr. Workman that involves a case of presyncope after transcatheter aortic valve replacement. Dr. Özeke has an ECG challenge reminding us that common things occur commonly. Dr. Zaha has a Perspective entitled, "Mending Broken Hearts, a New Treatment Paradigm for Immune Checkpoint Inhibitor Induced Myocarditis." And then finally, Dr. David Goff, the director of the NHLBI has a wonderful perspective piece (Special Report). And it really addresses some results from the Bethesda conference at the National Heart Lung and Blood Institute and the American Heart Association. And it was co-sponsored the bending curve of cardiovascular disease mortality, the Bethesda plus 40 years Symposium.
Dr. Greg Hundley:
The report, Carolyn, summarizes the relevant research, policy, and practice opportunities discussed at the symposium, including participant led discussion that explored the challenges and barriers in promoting cardiovascular health, across lifespan. And established a potential framework for observational research interventions that would begin in early childhood. Well, Carolyn, how about now we jump forward to that feature discussion.
Dr. Carolyn Lam:
All right, now we can go.
Dr. Greg Hundley:
Well, listeners, we are to the feature discussion today. And we have with us Dr. Chintan Dave from Rutgers University in New Jersey, and our own associate editor, Dr. Naveed Sattar from Glasgow, Scotland. Welcome gentlemen. Chintan, could you explain to us some of the background information that went into the construct of your study and then what hypothesis did you want to test?
Dr. Chintan Dave:
So just for background, so we know that artheriscraotic cardiovascular events in heart failure typically occur in higher prevalence in patients with type two diabetes. What's been really exciting in recent years is that certain second-line therapies, namely SGLT2 inhibitors and GLP-1 receptor agonist in these large cardiovascular outcome trials have shown to reduce the incidents of cardiovascular events. So from these trials, we can infer that SGLT2 inhibitors typically reduce heart failure hospitalizations, and also have an impact on 3P-MACE, which is just the composite of cardiovascular death, non-fatal MI and non-fatal stroke hospitalizations. While GLP-1 receptor agonist tend to reduce, also have an impact on 3P-MACE, but they also have some modest benefits in heart failure hospitalizations as well.
Dr. Chintan Dave:
So now that we know that these agents reduce cardiovascular risk, what's not known is, whether or not, if we can use these agents together to further maximize a reduction in cardiovascular events. So in the cardiovascular outcome trials the dual use of SGLT2 two inhibitors and GLP-1 receptor agonists was rare and ranged from between 0% to 5.3%. So as a starting point, we said, "Okay, let's look at observational data to see what happens when you add SGLT2 inhibitors to patients who are already using GLP-1 receptor agonist." And we hypothesized that, given the orthogonal pharmacodynamic effects on cardiovascular risk, adding SGLT2 inhibitors to existing GLP-1 receptor therapy should further reduce cardiovascular events.
Dr. Greg Hundley:
Very good. And can you describe for us your study population and study design?
Dr. Chintan Dave:
Sure. So we used three databases in the US. Two of these databases were commercial claims data, which is typically your employer based insurance plans, which have patients between the ages of 18 and 64. And we supplemented that data with Medicare fee for service claims, which have patients over the age of 65. So within these three databases, we identified patients who have a diagnosis of type two diabetes and are already a GLP-1 receptor therapy or GLP-1RAs and initiating either SGLT2 inhibitors or sulfonylureas.
Dr. Chintan Dave:
And after we identified this patient population, we controlled for several pertinent variables that could be considered confounders, including socio-demographic variables, diabetes complications, and cardiovascular conditions. And we had two primary endpoints. The first primary end point of interest was a composite cardiovascular endpoint, which is defined as the composite of non-fatal MI or nonfatal stroke hospitalizations in all cause mortality. The reason we used all cause mortality instead of cost specific mortality is basically because we didn't have information on cause of death. So we have to resort to a more generic definition of mortality in the composite cardiovascular endpoint. The second primary endpoint that we used was heart failure hospitalizations. So we then in this population, estimated hazard ratios using basically a time to event framework.
Dr. Greg Hundley:
Okay. And what were your results?
Dr. Chintan Dave:
So after applying the eligibility criteria in all three databases and after doing a one-to-one propensity score matching, we had 12,500 patients who initiated SGLT2 inhibitors and 12,500 patients in the sulfonylurea groups. For the true primary end points the addition of SGLT2 inhibitors to baseline GLP-1RA therapy was associated with a 22% decrease in the incidents of composite cardiovascular end point or an adjusted hazard ratio of 0.78. And the caught 95% confidence intervals were statistically significant. For the endpoint of heart failure hospitalizations, we noted a 36% decrease in the risk of heart failure hospitalizations with the adjusted hazard ratio being 0.64. And again, that was statistically significant as well.
Dr. Chintan Dave:
The CCE or the Composite Cardiovascular Endpoints was driven primarily by non-statistical decreases in the risk of MI by about 25%, in all cause mortality by about 32%. But we also found no effect on stroke, which is also in line with what others have reported. The other thing we looked at was also to look at any evidence for heterogeneity in treatment effects by presence of cardiovascular diseases. And we found no statistical significant difference in that aspect. The last thing we looked at also was to look at any evidence of heterogeneity by baseline cardiovascular disease in the patient groups. And we found no evidence to that effect.
Dr. Greg Hundley:
Very nice. Well, Naveed help us put this study in perspective with some of the other research that I know you're familiar with related to the use of SGLT2 inhibitors and GLP-1 receptor agonists.
Dr. Naveed Sattar:
Yeah. Thanks Greg. So as we all know, the biggest gains in diabetes in the last few years is these two costs of the trucks SGLT2 inhibitors and GLP-1. We believe and the evidence suggests that SGLT2s, are more cardiorenal in its benefits, and GLP-1 more atherothrombotic. So the hope is that if you combine these drugs, you get additional benefits, but there are no trials that have actually tested this. So this particular paper being kind of first observational, look at adding an SGLT2 versus another drug on top of a GLP-1, tries to get at that particular question. And it provides an early hint that yes, if you add an SGLT2 on top of the GLP-1, you get additional benefits. Giving us some insight that yes, you combine these two classes of drugs, you might get additional benefit in one drug on its own.
Dr. Naveed Sattar:
Of course, this is not trial. Some of our readers are going to be nihilist and will not believe the data because it's not a trial, but that's fine. But it's done as well as it possibly can. This observational propensity analysis is well matched. The data have some kind of external validity in the sense that the greatest benefits or risks reductions, but for heart failure post-acquisition, which is what we would believe ratio to inhibitors. So there is some sense of validity here, but clearly colleagues, they want to know, and I actually had a patient in the clinic on Tuesday who was on a GLP-1 and actually was an SGLT2. And I wanted to add the GLP-1. And this kind of evidence provides me some evidence of confidence that yes, by adding both drugs, I might get additional benefits in that one drug on its own.
Dr. Naveed Sattar:
So what you're going to ask next, Craig, and I'll give my answer first. What we really need to do now is actually do the trials. And I think the trials will predominantly work, adding GLP-1 on people who are on SGLT2, because I think more people will be initially an SGLT2 because it's a oral therapy. Then we'll add GLP-1. Although we do have a new oral GLP-1 in play as well. So, that's the kind of paradigm we're in. Some hints, the combination gives you more than the single drug and I think that's really quite promising for people.
Dr. Greg Hundley:
Very nice. So Naveed suggesting a clinical trial to confirm some of these results. Chintan, do you have anything to add? What study do you think or what area of investigation in this field do you feel is next in line?
Dr. Chintan Dave:
Yeah, I mean, I would just start by saying that I agree with everything that Naveed said in the sense that this is a starting point. And that I think the key take home from this study that sort of is going to be published is basically that not only do SGLT2 inhibitors reduce the cardiovascular events in patients using GLP-1 therapy, but the fact that the magnitude of this reduction is very similar. What was noted in cardiovascular outcome trials of SGLT2 inhibitors for GLP use was very minimal. In other words, you can super impose the cardiovascular benefit profile of the SGLT2 inhibitors, which were seen in trials two patients using GLP-1 therapy.
Dr. Chintan Dave:
Now the converse is what needs to be done next, basically, where we need to look at what happens when you add GLP-1 receptor agonist, to SGLT2 inhibitors, as Naveed just said. And he raised a really good point in that more patients are going to be on SGLT2 inhibitors, because they want to avoid GLP-1 receptor agonist because they don't want to use injectable therapies. Of course we have oral semaglatites maybe that may mitigate these issues. But the fact that that aspect is still unknown, could potentially be really good idea for future studies. So that potentially would be a nice, good step.
Dr. Greg Hundley:
Excellent.
Dr. Naveed Sattar:
Can I see one last thing, Greg? There is a trial coming this year called AMPLITUDE‐O, which is a GLP-1 trial, which does have a fair number of people on base than SGLT2s. We might be able to get a curly hint at that ongoing trial in the next six months to a year.
Dr. Greg Hundley:
Excellent. Well, we want to thank both Chintan Dave from Rutgers and our own associate editor, Dr. Naveed Sattar from Glasgow, Scotland. And really presenting information from US Claims databases highlighting the addition of SGLT2 inhibitors to GLP-1 receptor agonists and finding there was an association with a further reduction of cardiovascular risk relative to the use of GLP-1 agonists alone. On behalf of both Carolyn and myself, we want to wish you a great week. And catch you next week On the Run. This program is copyright of the American Heart Association, 2021.