Testing blood sugar levels of acute heart failure patients may be a simple and cost-effective way to determine patients at high risk of early death, further hospitalizations or the development of diabetes.
Acute heart failure syndromes (AHFS) account for a substantial number of emergency department (ED) visits annually and are associated with high short- and long-term mortality rates.
The purpose of a large study published online in the European Heart Journal was to evaluate the prognostic implications of blood glucose on a wide range of outcomes including early mortality, hospitalizations and incident diabetes in AHFS - an avenue of investigation the researchers considered to have not previously been fully elucidated.
Researchers from the Institute for Clinical Evaluative Sciences (ICES), the Peter Munk Cardiac Centre at the University Health Network, and the University of Toronto, Canada, analyzed a population-based cohort of 16,524 AHFS patients presenting to the ED in Ontario, Canada between 2004-2007.
The patients were aged 70-85 years, 8,115 (49%) were men and 9,275 (56%) did not have pre-existing diabetes. Patients whose initial blood glucose measurements were obtained more than 24 hours after presentation were excluded along with patients with initial blood glucose readings more than 33.3 mmol/L or less than 3.9 mmol/L.
Researchers compared patient outcomes against a reference group of patients with a blood glucose level range between 3.9-6.1 mmol/L.
Patients were subsequently classified according to previously defined blood glucose strata: 3.9-6.1 (referent), >6.1-7.8, >7.8-9.4, >9.4-11.1, and >11.1 mmol/L.
Heart failure may predispose 'people to developing diabetes'
Results of the study find that patients without pre-existing diabetes when compared to the reference group had a:
- 26% higher risk of death within 30 days from any cause with blood glucose levels 6.1-7.8 mmol/L
- 50% higher risk of death from any cause for blood glucose levels exceeding 11.1 mmol/L
- 28% higher risk of death from cardiovascular causes for levels between 6.1-7.8 mmol/L
- 64% higher risk of death from cardiovascular causes for levels between 9.4-11.1 mmol/L
- 61% higher risk of diabetes for glucose levels between 6.1-7.8 mmol/L
- 261% higher risk of diabetes for glucose levels exceeding 11.1 mmol/L.
As the patient's blood glucose levels rose, so did their risk of diabetes, with their risk rising 14% for every 1-mmol/L increase in blood glucose.
The study indicates that even if an individual arrives at the hospital with no prior diagnosis of diabetes and with blood sugar levels within a range that could be considered as "normal," if their levels are above 6.1 mmol/L, they are at a higher risk of developing diabetes and early death.
Associate Professor of Medicine, Dr. Douglas Lee, a senior scientist at the ICES, who led the research, says, "Among patients without pre-existing diabetes, the majority (51%) had blood glucose levels on arrival at the hospital that were within 'normal' limits but greater than 6.1 mmol/L. Our results suggest that all such patients should undergo further testing for diabetes before discharge. If the hospital tests show that their fasting blood glucose is not elevated, then they should be monitored subsequently for the development of diabetes as outpatients." He continues:
"Although diabetes is a known risk factor for developing heart failure, this is the first time that it has been shown that heart failure predisposes people to developing diabetes."
Among the 7,249 patients with pre-existing diabetes, 2,286 (31.5%) had blood glucose levels higher than 11.1 mmol/L and their risk of death from any cause within 30 days of arriving at the hospital with heart failure was increased by 48% when compared to the reference group of patients.
They also had a 39% increased risk of being hospitalized for diabetes-related reasons, such as hyperglycemia (high blood sugar levels), skin and soft tissue infections and amputations.
Amid patients with and without pre-existing diabetes, blood glucose levels above 9.4 mmol/L increased the risks of hospitalization by 9-15% for heart failure or cardiovascular causes.
"Our findings suggest that the measurement of blood sugar levels in all patients arriving at emergency departments with acute heart failure could provide doctors with useful prognostic information and could help to improve outcomes in these patients," comments Dr. Lee.
"It is a rapid, readily available and inexpensive test that could be used to enable doctors to quickly assess a patient's risk for a wide range of possible outcomes and to suggest appropriate screening strategies that should be put in place."
The researchers indicate that further measures could include greater attention to finding the best medical therapy and drug doses, in those with heart failure and adverse blood glucose profiles.
Prior work by the team suggests that hospitalizations for heart failure and cardiovascular causes are often increased amongst those with coronary heart disease.
Ruling out significant coronary heart disease may also be important in those who also have diabetes and heart failure. Lee concludes:
"For diabetics with heart failure and abnormally high blood glucose levels on arrival at the hospital, better control of these glucose levels, which could lead to further disease if not successfully treated, may also be important."
Medical News Today recently reported that three new studies reveal that a chemical called nitrate - found in green vegetables including spinach, lettuce and celery - may aid heart health and reduce the risk of obesity and diabetes.