The deadly duo of diabetes & heart failure

Sad fact: Diabetes and heart failure make a deadly combination.

Sadder fact: Both diabetes and heart failure are becoming extremely common diseases in the Philippines, and can be expected to co-exist in many Filipino patients.

Heart failure is the impairment of heart function (usually involving the left ventricle, the heart’s main pumping chamber), resulting in fatigue, shortness of breath and edema (manas).

Diabetes is an abnormally elevated blood sugar leading to damage of blood vessels and vital organs throughout the body (including the heart, brain, eyes, kidneys, nerves, etc.).

Studies show a clear association between heart disease and diabetes. The prevalence of coronary artery disease (CAD) is more than doubled in diabetics compared to non-diabetics, and the risk of heart failure likewise increases. In fact, deaths due to heart disease triple among diabetics compared to non-diabetics. After a heart attack, diabetics have twice the risk of death and triple the rate of progression to heart failure compared to non-diabetics.

What makes diabetes so dangerous for heart failure patients and vice versa? Firstly, diabetes causes more severe and extensive blockage of the blood vessels supplying the heart muscle, thus weakening it more than usual. Secondly, abnormal substances may be deposited within the heart muscle (glycoproteins), causing further impairment of its pumping action.

Thirdly, diabetes may prevent the heart from utilizing sugar as fuel and instead force it to use fatty acids, causing the heart to use up more oxygen that may already be in short supply. Diabetes may also predispose toward abnormal blood clotting, which could totally block already partially blocked blood vessels, thus causing a full-blown heart attack.

Special handling

All these points may become important when treating diabetics with heart failure, and these patients definitely require special handling. For example, diabetic nerve damage may mask chest pain (angina), thus leading to under-treatment of ongoing ischemia (lack of oxygen in the heart), which may aggravate the heart failure even more.

Poor control of blood sugar, especially sudden elevations, can aggravate heart failure, which, in turn, can trigger more episodes of poor control, giving rise to a vicious cycle. Thus, this situation means that additional care should be given to controlling blood sugar at all times, both when the heart failure is stable and during episodes of exacerbation.

The most important point to be emphasized is vigorous treatment of risk factors that may aggravate cardiovascular illness and deaths in diabetics. These risk factors include high blood pressure, high levels of blood cholesterol, obesity and cigarette smoking. They should be addressed immediately and with all due diligence, on the part of both the physician as well as the patient.

If a diabetic already has heart failure, some drugs may help. Digitalis enhances pumping ability of the heart muscles. Diuretics get rid of the excess fluids. Betablockers, aldosterone antagonists and angiotensin converting enzyme inhibitors such as perindopril (Coversyl) may all reduce the risk of death and improve life expectancy.

Patients with co-existing diabetes and heart failure are an extremely high-risk group. A strict healthy lifestyle change with aggressive treatment of risk factors can go a long way for these patients to continue living happy and productive lives. And that’s the good news!

(The author is a consultant cardiologist of the Philippine Heart Center and currently the vice president of the Heart Failure Society of the Philippines. He is a member of the Charter Bureau, a non-stock, non-profit research foundation based at the Manila Adventist Medical Center, which promotes healthy lifestyle changes in preventing common medical problems.)