Diabetes Predicts Worse Survival in Heart-Failure Patients

Marlene Busko

October 01, 2014

VIENNA — Among patients with heart failure of ischemic origin or heart failure with preserved ejection fraction, those who also had type 2 diabetes had a worse 2- to 8-year survival, new data from 2 studies using the Swedish Heart Failure Registry indicate.

The findings were reported in 2 oral presentations here at the European Association for the Study of Diabetes 2014 Meeting.

The first study showed that 30% of patients with ischemic heart failure in this registry had type 2 diabetes, and diabetes was independently linked with a 70% greater risk for mortality during follow-up, Anna Norhammar, MD, from Karolinska Institutet, in Stockholm, Sweden, reported.

Only two-thirds of these patients with ischemic heart disease and type 2 diabetes had received statins, and only half had undergone revascularization.

"Maybe an early identification of coronary artery disease, improved treatment, and more optimized timing of revascularization might prevent heart-failure development and improve the prognosis of patients with diabetes," Dr. Norhammar speculated.

The second study determined that a quarter of patients with heart failure and preserved left ventricular ejection fraction had type 2 diabetes, which was associated with a 39% increased risk for mortality during follow-up, Isabelle Johansson, MD, also from Karolinska Institutet, reported.

Two experts who were not involved in the research told Medscape Medical News that the new studies help quantify and draw attention to the important increased risk for earlier mortality in patients with type 2 diabetes and heart failure and suggest that some of these patients may be undertreated.

Impact of Diabetes on 2 Types of Heart Failure

The current prevalence of heart failure (2%) and type 2 diabetes (8%) will likely increase as the population ages and survival after a myocardial infarction continues to improve, Dr. Norhammar said.

Thus, "more patients with diabetes will survive a myocardial infarction, and they will live with chronic ischemic heart disease and possibly develop heart failure," so it is important to know more about the prevalence and prognosis of these patients, she explained.

Her study looked at the impact of type 2 diabetes on the long-term prognosis in patients with ischemic heart failure.

She and her colleagues examined data from 17,673 patients who were enrolled in the Swedish Heart Failure Registry from 2003 to 2011, had heart disease of ischemic origin, were seen in a hospital or a specialized heart-failure clinic, and followed until December 2011 (a median of 22.5 months).

Compared with patients with no diabetes, those with type 2 diabetes were slightly younger (a mean age of 75 vs 77) and were more likely to have hypertension (59% vs 45%) and heart-failure symptoms (NYHA class 3/4, 53% vs 46%).

Somewhat surprisingly, the ejection fraction was the same in both groups (17% had an EF > 50%), and patients with diabetes were more likely to have preserved renal function (estimated glomerular filtration rate [eGFR] > 60 mL/min; 44% vs 38%).

Among patients with diabetes, 61% were receiving an ACE inhibitor, 67% were taking statins, 88% were on a beta-blocker, and 71% took aspirin.

After correction for multiple covariates, the odds ratio for mortality during follow-up was 1.71 for patients with vs without diabetes.

The second study aimed to determine the impact of type 2 diabetes on the long-term prognosis in patients with preserved ejection fraction. Data from 6705 patients enrolled in the registry at the same time as the first study, who had preserved left ventricular ejection fraction (defined as LVEF > 50%), were assessed.

After correction for the same multiple covariates, the odds ratio for mortality during follow-up was 1.39 for patients with vs without diabetes.

However, as many as 50% of the patients with preserved left ventricular function had reported ischemic heart disease, "which questions the concept of a pure diabetic cardiomyopathy," the researchers noted.

Greater Mortality Risk, Possible Undertreatment

Asked to comment, heart-failure expert John JV McMurray, MD, from the University of Glasgow, Scotland, said: "It is well-known that in patients with heart failure, diabetes is associated with a substantial, significant increased risk of death and other poor outcomes; thus, the present abstracts really just reinforce what we know (which is not unimportant)."

Patients with diabetes may be "undertreated with effective heart-failure therapies (such as beta-blockers) and, of course, there is the lingering concern that some treatments for diabetes [thiazolidinediones, dipeptidyl peptidase 4 (DPP-4) inhibitors, and metformin in patients with renal and hepatic dysfunction] may be harmful in patients with heart failure," he added.

The 2 studies highlight the need for clinicians to aggressively apply evidence-based therapies for patients with heart failure and type 2 diabetes and for researchers to develop specific therapies and determine optimal treatment strategies for these patients, added Darren McGuire, MD, from University of Texas Southwestern Medical School, Dallas.

The first study again shows that "patients with type 2 diabetes suffer more from heart-failure symptoms, die more often, and die at much younger age," he observed.

It also hints that patients with diabetes and ischemic heart failure were not always receiving guideline-recommended therapies: "While beta-blocker use was appropriately high, use of ACE inhibitors, statins, and aspirin was extremely low."

And in the second study, "although the observed higher adjusted mortality with type 2 diabetes [and preserved ejection fraction] is not a surprising finding, it does provide quantitative estimation largely lacking in the available data," Dr. McGuire said.

Dr. Norhammar has received reimbursement from AstraZeneca and Merck Sharpe & Dohme for advisory boards and lectures and travel support from Novo Nordisk, Merck Sharpe & Dohme, Roche, and Eli Lilly. Dr. Johannson has received travel support from Novo Nordisk and Roche. Dr. McMurray has reported no relevant financial relationships. Dr. McGuire has received honoraria for trial leadership and consultation with GlaxoSmithKline, Takeda Pharmaceuticals, Novo Nordisk, Janssen, Eli Lilly, Bristol-Myers Squibb, AstraZeneca, Boehringer Ingelheim, Merck, Regeneron, Lexicon, Genentech, and Roche.

European Association for the Study of Diabetes 2014; September 16, 2014; Vienna, Austria. Abstract 44, Abstract 45

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