Drawing on data from 31,546 high-risk patients participating in two international trials, researchers found that even small increases in fasting glucose raised the risk of congestive heart failure in both diabetes patients and those whose blood sugar fell within the normal range.
"This illustrates that blood glucose by itself is a continuous risk factor for developing heart failure because all of these patients were free of heart failure when they enrolled in the trials," said Claes Held, M.D., Ph.D., lead author of the study.
"However, these are only associations," said Held, an associate professor of cardiology at the Karolinska Institutet in Stockholm, Sweden. "They do not prove that elevated blood glucose causes heart failure. To demonstrate a causal relationship, you would have to do a study that showed lowering blood glucose levels would reduce the incidence of heart failure."
About 5.2 million Americans evenly divided between males and females suffer from heart failure, according to the American Heart Association. Each year about 550,000 new cases are diagnosed and about 57,700 people die from it. Heart failure is a debilitating condition in which the heart fails to pump an adequate supply of blood throughout the body. Established heart failure risks include uncontrolled high blood pressure, diabetes and heart attack.
To examine the relationship between blood glucose levels and congestive heart failure, Held and colleagues performed an interim analysis on the blinded data from the ONgoing Telmisartan Alone and in combination with the Ramipril Global Endpoint Trial (ONTARGET) and Telmisartan Randomized AssessmeNt Study in aCE iNtolerant subjects with cardiovascular Disease (TRANSCEND) trials. Both were randomized, controlled, parallel clinical studies testing drug regimens aimed at reducing fatal and nonfatal cardiovascular events. ONTARGET had 25,620 patients enrolled and TRANSCEND had 5,926, and both included patients with and without diabetes. Researchers obtained fasting blood glucose levels for patients when they entered the trials and periodically thereafter.
"We know that diabetes is a strong risk factor for cardiovascular disease including heart failure, but these studies included patients with and without diabetes," Held said. "This was a great opportunity to evaluate a broad population of high-risk individuals and study the association between blood glucose and cardiovascular disease, regardless of the diabetic state."
Patients in the two trials were average age 67 at entry, and 69 percent were men. Thirty-seven percent had been previously diagnosed with diabetes and 3.2 percent were diagnosed with the disease at the time of entry.
Patients were assigned to five groups based on their entry fasting blood glucose levels, measured in millimoles per liter of blood, or mmol/L. The lowest group had an average fasting blood glucose of 4.6 mmol/L and the highest had an average reading of 8.5 mmol/L.
The mmol/L is the international standard unit for measuring blood glucose. In the United States, blood glucose levels are usually reported in milligrams per deciliter, mg/dL. Multiplying the number of mmol/L by 18 converts the number to mg/dl.
Researchers analyzed data from patients with an average follow-up of 2.4 years. During this time there were:1,067 cardiovascular deaths
Similarly, a 1 mmol/L rise increased the risk of congestive heart failure hospitalization or cardiovascular death by 9 percent for all patients, by 3 percent for patients without diabetes and by 5 percent for patients with diabetes.
"Even in the normal range, our results indicate that elevated blood glucose is associated with the risk of heart failure," Held said. "You can look at blood glucose much like blood pressure or cholesterol. Even if you have normal blood glucose, there is a gradual increase in risk wherever you start on the scale. If the blood sugar is "high normal" there is a higher risk than those with "low normal fasting blood glucose levels."
He and colleagues suggested several potential mechanisms for rising glucose levels which increase the risk of developing congestive heart failure.
"Individuals with disturbances in their glucose regulation usually have more coronary artery disease, which is a well known underlying risk factor for heart failure," Held said. "That is a strong explanation for our findings but the others are more speculative and hypothetical."
Karen Astle | EurekAlert!
Monitoring the heart's mitochondria to predict cardiac arrest?
21.09.2017 | Boston Children's Hospital
Highly precise wiring in the Cerebral Cortex
21.09.2017 | Max-Planck-Institut für Hirnforschung
Our brains house extremely complex neuronal circuits, whose detailed structures are still largely unknown. This is especially true for the so-called cerebral cortex of mammals, where among other things vision, thoughts or spatial orientation are being computed. Here the rules by which nerve cells are connected to each other are only partly understood. A team of scientists around Moritz Helmstaedter at the Frankfiurt Max Planck Institute for Brain Research and Helene Schmidt (Humboldt University in Berlin) have now discovered a surprisingly precise nerve cell connectivity pattern in the part of the cerebral cortex that is responsible for orienting the individual animal or human in space.
The researchers report online in Nature (Schmidt et al., 2017. Axonal synapse sorting in medial entorhinal cortex, DOI: 10.1038/nature24005) that synapses in...
Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...
Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!
When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...
For the first time, physicists have successfully imaged spiral magnetic ordering in a multiferroic material. These materials are considered highly promising candidates for future data storage media. The researchers were able to prove their findings using unique quantum sensors that were developed at Basel University and that can analyze electromagnetic fields on the nanometer scale. The results – obtained by scientists from the University of Basel’s Department of Physics, the Swiss Nanoscience Institute, the University of Montpellier and several laboratories from University Paris-Saclay – were recently published in the journal Nature.
Multiferroics are materials that simultaneously react to electric and magnetic fields. These two properties are rarely found together, and their combined...
MBM ScienceBridge GmbH successfully negotiated a license agreement between University Medical Center Göttingen (UMG) and the biotech company Tissue Systems Holding GmbH about commercial use of a multi-well tissue plate for automated and reliable tissue engineering & drug testing.
MBM ScienceBridge GmbH successfully negotiated a license agreement between University Medical Center Göttingen (UMG) and the biotech company Tissue Systems...
19.09.2017 | Event News
12.09.2017 | Event News
06.09.2017 | Event News
21.09.2017 | Physics and Astronomy
21.09.2017 | Life Sciences
21.09.2017 | Health and Medicine