Diabetes a Silent Cardiac Threat: Experts Warn of Hidden Heart Disease Risk

Diabetes does not announce itself as a heart threat. A man walks into an emergency room at 45, convinced he has indigestion from rich food and spices. His electrocardiogram tells a different story. All three of his coronary arteries are completely blocked. He has been diabetic for a decade, taking his medications sporadically, with no prior heart attack, no chest pain, no warning at all. When doctors told him he needed bypass surgery, he was bewildered. How could this have happened without him knowing?

This is the central puzzle that cardiologists are now pressing their colleagues to understand: diabetes damages the heart silently, often for years, before a person feels anything wrong. Dr. Ashwin Mehta, who directs the Heart Failure Programme at Sir Ganga Ram Hospital in New Delhi, describes diabetes as a "very big driver of heart disease" because of the cascade of damage it sets in motion. When blood sugar stays elevated over time, it triggers a chain reaction. The high glucose itself becomes toxic to blood vessel linings—a process called endothelial dysfunction. Insulin resistance develops. Systemic inflammation spreads through the body. The protective molecule nitric oxide, which helps keep vessels healthy, begins to disappear. At the same time, cholesterol and triglyceride levels climb, making vessel walls more vulnerable to plaque buildup. Hypertension often arrives alongside diabetes, compounding the risk further.

The research is unambiguous. Studies have shown that over the long term, diabetes creates so much cardiovascular damage that physicians now treat every diabetic patient as though they already have coronary artery disease or have already suffered a heart attack. The medical term for this is "myocardial risk equivalent"—a way of saying that the statistical danger is equivalent, even if no event has yet occurred. The 45-year-old man's case was not an anomaly. It was, in fact, typical of what happens when diabetes goes uncontrolled or undertreated.

But there is a second, more insidious layer to this danger: diabetic patients often cannot feel it happening. Nerve damage—a common complication of diabetes itself—damages the pain signals that normally alert a person to heart trouble. The alarm system fails. A person can be experiencing ongoing cardiac injury without chest pain, without shortness of breath, without any sensation that something is wrong. Dr. Naresh Trehan, Chairman of Medanta hospital, has seen this repeatedly in his practice. Patients arrive in his office with heart function that has declined to 20 percent—a severe reduction—and they had no idea. They only sought help when they began to feel short of breath, by which point significant damage had already accumulated.

This is why both experts are now calling for a fundamental shift in how diabetes is managed. Physicians treating diabetic patients must ensure that their patients receive regular cardiac evaluations—an echocardiogram or heart check annually, or every two years if the condition is stable. The current standard of care often does not include this. A diabetologist or internist may manage blood sugar levels without ever coordinating with cardiology or ordering the imaging that would reveal silent heart damage. Trehan emphasizes that doctors have a responsibility to explain these risks to their patients and to make sure the appropriate screenings happen. "If somebody has heart disease, we give them the prescription," he said. "If the internist or a diabetologist is treating a diabetes patient, they should make sure that they get their checkup because these are important things for protecting life." The gap between what we know about diabetes and heart disease, and what patients and their primary care doctors actually do about it, remains wide. Closing it may require nothing more than routine vigilance—but that routine has not yet become standard.