Diabetes and heart failure: A deadly connection
By Dr Mohunlall Soowamber BSc, MD, LMCC
There are actually about 463 million people globally suffering from diabetes. Mauritius is one of the leading countries with over 20% of its population diagnosed as diabetics.
The challenge in diabetes treatment is overwhelming as it is not simply a question of controlling blood sugar, cholesterol and blood pressure. It is a multisystemic disease i.e. it affects all organs from head to toe. In the last five years, research has provided us with tools not only to achieve our recommended targets of HbA1C, LDL and blood pressure, but allows us to go beyond these criteria.
Nowadays, the focus is on the profile of the patient: with or without atherosclerotic disease (which narrows arteries), with or without heart failure or renal disease.
The diabetic patient is at high risk of heart failure due to a problem of the:
Pump (the heart) – heart failure
Pipes (the arteries) – coronary artery disease
Filters (the kidneys) – renal disease
In heart failure, the heart is unable to pump enough blood to bring oxygen to all the organs.
Statistically, the diabetic patient will experience heart failure before having a heart attack or a stroke. The main risk factors for heart failure in the diabetic patient are the pump itself which can suffer from a direct effect of inflammation in the small arteries of the heart, a disease of the heart muscle which affects its contraction and relaxation. And if the pipes (arteries) are clogged, the heart will not be able to supply the demands of the organs for oxygen.
The filters (kidneys) are also connected to the heart; we call it the cardio-renal connection. As the kidneys get damaged, so does the ability of the heart to pump blood. Chronic kidney failure is linked to heart failure as the latter worsens with poor kidney function.
What are the signs and symptoms of heart failure?
They may go unnoticed at the beginning. Later they manifest as fatigue, palpitations, shortness of breath on exercise, having to add more pillows to sleep in a more comfortable position, swelling of feet and ankles.
On examination of the patient, the doctor may hear abnormal sounds in the heart, or notice increase of pressure in the jugular vein of the neck, wheezing or rales on auscultation of the lungs.
The doctor can order an ultrasound of the heart which is the preferred test in heart failure. If the patient is suspected to have angina which may be silent, an angiogram can be ordered along with scan or MRI of the heart.
Since a few years, a blood test consisting of measuring BNP (which is a substance produced by the strain on the ventricles) has been available. Depending on age, there are values above which we can predict a failing heart.
Are there any new strategies for pharmacologic treatments?
Of course, we use:
- Betablockers (ex: bisoprolol, metoprolol, carvedilol). Start low, go slow. This class of medications decreases mortality by 34%.
- ACE inhibitors or ARA (ex: enalapril, candesartan). These drugs decrease mortality by 16-17%.
- MRA (mineralo-corticoid receptor antagonist): Aldactone, Eplerenone. These agents decrease mortality by 30%.
4) ARNI (angiotensin receptor antagonist and neprilysin inhibitor). Ex: sacubitril-valsartan. In a landmark study called Paradigm HF this combo drug was found to decrease mortality by 20% and hospitalisations for heart failure by 20%.
What about the residual risk?
Fortunately there is good news. Data from recent trials show that, in diabetics as well as non-diabetics, the use of agents called SGLT2 inhibitors can reduce hospitalisations for heart failure or cardiovascular death by 25-26%.
In conclusion, the diabetic patient is at high risk of suffering from heart failure. Heart failure patients have a poorer prognosis over five years than most cancers except lung cancer. The death rate is high in patients with heart failure, about 25% per year depending on the NYHA classification (New York Heart Association). We must be able to diagnose heart failure early and be mindful that it can lead to sudden death.
Nowadays, we can help diabetic patients avoid the complication of heart failure by bringing the best medications available to them, so as to provide them with a longer and better quality of life.
* * *
Dr Mohunlall Soowamber holds a Bachelor’s degree in Biochemistry from McGill University and completed his medical training at the Université Besançon in France. He was previously a member of the Club de Recherches Cliniques du Québec and has conducted research in many areas, namely asthma, COPD, diabetes, dyslipidemia, hypertension, osteoporosis and renal function. He has also been a member of the Fédération des Médecins omnipraticiens du Québec (FMOQ) since 1984 and is now actively involved in its oversight of continual medical education programs that are presented in the province of Québec. He is presently Moderator & Directeur de la clinique médicale L’Espérance, Montréal.
* Published in print edition on 6 November 2020
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