LOS ANGELES –
They also may play a role in the treatment of patients with known heart failure (HF), but further studies are required to prove definite treatment benefit.
“These trials enrolled a minority of patients with known heart failure, and, in those subgroups, the drugs seems to reduce the risk for hospitalization, opening the possibility of treatment benefit,” Javed Butler, MD, said at the World Congress on Insulin Resistance, Diabetes & Cardiovascular Disease. “But there were not enough patients to conclude this. If you are treating diabetes with these agents in patients with heart failure, more power to you. But don’t think you are treating heart failure per se until the results of the dedicated heart failure trials come out.”
Good glycemic control has not been shown to affect heart failure outcomes per se, said Dr. Butler, professor and chairman of the department of medicine at the University of Mississippi Medical Center, Jackson.
“People seem to mix the concepts of prevention and treatment together,” he said. “We have now very good evidence across all trials with SGLT-2 inhibitors for prevention of heart failure. But for treatment, we need more data despite favorable early signals.
“Also, these trials include most patients with ischemic heart disease, but we don’t have data on nonischemic etiology for the development of heart failure from these trials,” Dr. Butler added.
The best available data from clinical trials suggest that patients with American College of Cardiology Foundation/American Heart Association heart failure classification stages A and B benefit the most from aggressive treatment to prevent HF.
“Either they have diseases like high blood pressure or diabetes, but their hearts are normal, or, perhaps, their hearts are abnormal, and they develop left ventricular hypertrophy or atrial fibrillation,” he said. “However, if someone is stage C – manifest heart failure – or stage D – advanced heart failure – we need further data on novel therapies to improve their outcomes.”
Dr. Butler emphasized that not all heart failure is associated with atherosclerotic vascular disease. In fact, the Health, Aging, and Body Composition Eur J Heart Fail. 2014 May;16:526-34). “There’s a whole other world of nonischemic heart failure that we also need to worry about,” he said. “There is a lot of microvascular endothelial dysfunction.”showed that the incidence of heart failure increased progressively across age groups, both for those with and without a preceding vascular event (P = .03 and P less than .001, respectively;
The combination of heart failure and diabetes is especially lethal. “If you put them together, you’re looking at about a 10-fold higher risk of mortality, which is a horrible prognosis,” Dr. Butler said. “That means that we need to think about prevention and treatment separately.”
“The other classes of drugs either increase the risk, or we don’t have very good data,” Dr. Butler said. “So far, across the spectrum of therapies for diabetes, the effect on heart failure is neutral and perhaps confers some risk.”
SGLT-2 inhibitors convey a different story.
In the EMPA-REG OUTCOME Trial, one inclusion criterion was established cardiovascular disease (CVD) in the form of a prior MI, coronary artery disease, stroke, unstable angina, or occlusive peripheral artery disease, but not heart failure alone (“This was not a heart failure study, so we don’t know what their New York Heart Association class was, or the details of their baseline HF treatment in the minority of patients who were enrolled who had a history of HF,” Dr. Butler cautioned.
However, the trial found that empagliflozin conferred an overall cardiovascular death risk reduction of 38%, compared with placebo. When the researchers assessed the impact of treatment on all modes of cardiovascular death, they found that death from heart failure benefited the most (hazard ratio, 0.32; P = .0008), while sudden death benefited as well. Empagliflozin also had a significant impact on reduced hospitalization for heart failure, compared with placebo (HR, 0.65).
“This is a large enough cohort that you should feel comfortable that this drug is preventing heart failure in those with HF at baseline,” said Dr. Butler, who was not involved with the study. “We can have a debate about whether this is a treatment for heart failure or not, but for prevention of heart failure, I feel comfortable that these drugs do that.”
A subsequent study of canagliflozin and cardiovascular and renal events in type 2 diabetes showed the same resultIt reduced hospitalization for heart failure by 33% (HR, 0.67).
Then came thestudy, which found low rates of hospitalization for heart failure and all-cause death in new users of SGLT-2 inhibitors. More recently, yielded similar results.
“One of the criticisms of these findings is that heart failure characteristics were not well phenotyped in these studies,” Dr. Butler said. “I say it really does not matter. Heart failure hospitalizations are associated with a poor prognosis irrespective of whether the hospitalization occurred in patients without heart failure or in a patient with previously diagnosed heart failure, or whether the patient has reduced or preserved ejection fraction.
“Framingham and other classic studies show us that 5-year mortality for heart failure is about 50%,” he noted. “If you can prevent a disease that has a 5-year mortality of 50%, doesn’t that sound like a really good deal?”
A contemporary appraisal of the heart failure epidemic in Olmstead County, Minn., during 2000-2010 found that the mortality was 20.2% at 1 year after diagnosis, and 52.6% at 5 years after diagnosis. The data include new-onset HF in both inpatient and outpatient settings.
Specifically, new-onset HF hospitalization was associated with a 1-year post discharge mortality of 21.1%“We cannot ignore prevention of heart failure,” Dr. Butler said. “Also, for treatment, once you get hospitalized for heart failure, the fundamental natural history of the disease changes. There is a 30% cumulative incremental death risk between the second and third hospitalizations.”
Dr. Butler concluded his presentation by noting that five randomized, controlled trials evaluating SGLT-2 inhibitors in HF have been launched, and should help elucidate any effects the drugs may have in treating the condition. They include EMPEROR-Preserved, EMPEROR-Reduced , Dapa-HF , and SOLOIST-WHF and DELIVER .
Dr. Butler disclosed that he has received research support from the National Institutes of Health, the European Union, and the Patient-Centered Outcomes Research Institute. He has also been a consultant for numerous pharmaceutical companies, including Boehringer Ingelheim, Janssen, and AstraZeneca, which sponsored the EMPA-REG, CANVAS, and DECLARE TIMI 58 trials.