Aerobic Fitness Helps Predict Risk of Heart Failure in Diabetics

Gaurav Gulsin, MBChB

A new study from investigators at the National Institute for Health Research is shedding new light on potential signs of cardiovascular impairment in patients with type 2 diabetes.

Results of the study indicate myocardial percussion reserve and diastolic functions could help signal diabetic patients who may be at an increased risk of developing heart failure later in life.

"Our results showed that even when factoring in age, sex, ethnicity and smoking status, subtle heart impairments contributed to strikingly poor fitness in the volunteers with type 2 diabetes,” said lead investigator Gaurav Gulsin, MBChB, a British Heart Foundation Clinical Research Training Fellow at the University of Leicester, in a statement. “This suggests that early heart disease is already present in this population, despite the absence of clinical indicators, such as angina and shortness of breath."

With type 2 diabetes associated with an increased risk of cardiovascular comorbidities and research suggesting diabetics free from signs or symptoms of cardiovascular issue still experience limited exercise capacity, investigators sought to determine what markers could allow for greater prediction of future declines in cardiovascular health. With this in mind, Gulsin and a team of fellow investigators designed a study to evaluate associations between subclinical cardiac dysfunction and aerobic exercise capacity in adults with type 2 diabetes.

Using pooled data from individuals enrolled in 1 of 4 previous studies performed by study investigators, investigators enrolled 247 adults with type 2 diabetes and 78 matched, healthy control subjects. Of note, all patients were 18-75 years of age and had no prior history, clinical signs, or symptoms of cardiovascular disease. Additionally, patients were excluded from the analysis if they had type 1 diabetes, stage 4 or 5 chronic kidney disease, and known macrovascular disease.

The mean age of the diabetic group was 51.8±11.9 years, 55% were male, and 37% were black or of south Asian ethnicity. The mean HbA1c measurement of this group was 7.4±1.1% (57±12 mmol/mol) and mean duration of diabetes was 61 (32-120) months.

As part of the study, all participants underwent bioanthropometric profiling, cardiopulmonary exercise testing, and cardiovascular magnetic resonance with adenosine stress perfusion imaging. Investigators used results from this battery of tests and imaging in multivariable linear regression analyses to identify independent associations between measures of cardiovascular structure and function with peak VO2.

The investigators’ analyses revealed patients with type 2 diabetes, compared to those without, had greater concentric left ventricular remodeling, reduce myocardial perfusion reserve, and a lower aerobic exercise capacity (peak VO2, 18.0±6.6 vs 27.8±9.o mL/kg/min; P <.001).

Results of a multivariable linear regression model indicated only myocardial perfusion reserve and left ventricular diastolic filling pressure were independently associated with peak VO2 in diabetic patients, after adjustment for age, sex, ethnicity, smoking status, and systolic blood pressure.

“If we can target these subtle heart impairments with treatments to increase blood supply to the heart, we may help to improve fitness levels and reduce the risk of heart failure in people with type 2 diabetes,” said Gerry MCCann, MD, professor of Cardiac Imaging at the University of Leicester. "We're now keen to explore such different treatment options to see which, if any, provide the best health outcomes for patients."

This study, “Cardiovascular determinants of aerobic exercise capacity in adults with type 2 diabetes,” was published in Diabetes Care.