ICS 2012 Report – The hidden truth – Stage B heart failure in diabetics and the overweight

by Edel O’Connell reporting on a presentation by Dr. Gillian Murtagh.

Murtagh G, O’ Connell J, Dawkins I, King T, Griffin J, Tallon E, O’ Hanlon R, Patel A, Ledwidge M, Mc Donald KM St Vincent’s University Hospital.

Diabetes mellitus (DM) is an independent predictor of heart failure (HF).

“The optimal approach to this problem involves identifying patients at risk early in the course of the condition. Previous studies have shown a high prevalence of diastolic dysfunction in diabetic subjects. We set out to study the wider burden of structural and functional problems that could lead to heart failure,” explained Dr Murtagh.

About 15,000 people in Ireland have diabetes and heart failure at an estimated cost of €450 million a year- 70pc of that cost is associated with ADHF hospitalisation.

“We know there is an obesity epidemic in progress and Irish men are the heaviest in Europe. We are also well versed in the association of obesity and increased risk of heart failure. There is a long association between diabetes and heart failure as demonstrated by the 30-year framework follow-up which correlates with similar findings,” commented Dr Murtagh.

Data from the recent Atherosclerosis Risk in Communities (ARIC) study cohort demonstrated how at population level, diabetes is a stronger risk factor for new heart failure than four other modifiable risk factors, namely smoking, dyslipidemia, obesity, and even hypertension.

This is attributed to coronary heart disease but Dr Murtagh explains there is also an independent process.

“We think there are multiple structural and functional problems with the diabetic heart, such as fibrosis and autonomic neuropathy. They have reduced levels of adrenaline in the myocardium at autopsy and there are also functional problems such as reduced expression activation of the sodium potassium pump and reduced calcium sensitisation,” she added.

The researchers then set out to prove that there is an increased prevalence in Stage B heart failure in Irish diabetics and the overweight.

“This identified a particularly high-risk group requiring more intensive risk factor control,” explained Dr Murtagh.

Using the Stop HF cohort- which is comprised of people  over 40 with at least one cardiovascular risk factor- Dr Murtagh tells how they eliminated not only those with heart failure but also moderate regurgitation, coronary artery disease and atrial defibrillation.

“We wanted to look at the independent process,” she added.

The study then looked at 1,320 people.

Results demonstrated BPN was significantly different between the diabetics and the non diabetics, at 19 for the diabetics and 12 in non diabetics.

“When we matched a cohort of 800 people for age and sex things became a lot more significant. Throughout all of the different elements we picked there was a statistically significant difference,” she said.

Though asymptomatic, a significant proportion of the diabetic population had stage B Heart failure, particularly those with a BMI of 30 kg/m2.

There were 303 patients (33 percent) with a BMI 30 kg/m2 – of this obese cohort, 82 (27 percent) had diabetes.

Prevalence of Stage B heart failure in the obese was 32percent overall.

When comparing diabetic obese versus non-diabetic obese, Stage B Heart Failure was present in 44percent of the diabetic obese compared to 28 percent in the non-diabetic obese.

“The diabetics consistently- whether they were, obese, hypertensive, or over- 65, had higher rates of Stage B heart failure,” according to Dr Murtagh.

“At a time of limited resources, this identifies a cohort of patients requiring more intensive risk factor control to prevent progression to symptomatic heart failure,” she added.

Stage B patients have structural heart disease but are asymptomatic if the condition is allowed to progress to Stage C the survival rate drops dramatically.

Thus early identification is critical in order to reduce the poorer cardiovascular outcomes in particular heart failure.

Dr Murtagh alluded to the new clinical guidelines on Type 2 diabetes published by the Royal College of General Practitioners in Sheffield which demonstrate new instances of heart failure could be reduced by as much as 56pc through targeted intervention.

“Diabetes and obesity and heart failure are all rising- prevention is the answer. Stage B is more prevalent in the diabetic and risk factors are really not under control. We should target the highest risk people, consider referring them to specialist services and if we could achieve a 10pc drop in the incidence of heart failure we would be saving millions of euro. A lot of diabetic people probably have Stage B heart failure. If their risk factors are allowed to progress uncontrolled they will progress to Stage C and will cost our economy a huge amount of money,” she added.