How Diabetes Increases Heart Risk and What You Can Do About It

Last updated 14 July 2026

Most of us think of diabetes as a sugar problem. You watch your teh tarik, you skip the kuih, you check your numbers. But diabetes is not really a disease of sugar in the blood. It is a disease of blood vessels. And the most important ones it damages are the vessels that feed your heart.

This matters a great deal in Malaysia. The National Health and Morbidity Survey (NHMS) 2023 is run by the Institute for Public Health under the Ministry of Health. It found that 15.6% of Malaysian adults have diabetes, roughly one in six. Separately, the Department of Statistics Malaysia (DOSM) reported that ischaemic heart disease was the leading cause of death in Malaysia in 2024. It caused 17,421 deaths, or 13.0% of all medically certified deaths. These two facts are not a coincidence. They are the same story told twice.

The Malaysian Picture

The NHMS 2023 numbers are worth sitting with. The risk factors for heart disease travel together, in the same people. Every figure in the table below comes from that same national survey.

Among Malaysian adults	Prevalence (NHMS 2023)
Diabetes (overall)	15.6%
of which: already diagnosed	9.7%
of which: raised blood glucose, not previously known	5.9%
High blood pressure	29.2%
High cholesterol	33.3%
Overweight or obese	54.4%
Physically inactive	29.9%

Look at the third row. Of the 15.6% with diabetes recorded by NHMS 2023, 5.9 percentage points did not know they had it: nearly two in five, undiagnosed. Malaysia’s Clinical Practice Guidelines on Type 2 Diabetes (6th Edition) are issued by the Ministry of Health. They are blunter still. They recommend annual screening from age 30, because “~50% of people with diabetes are undiagnosed.”

That is the killer statistic. Undiagnosed diabetes does not pause while you are unaware of it. The arteries are being damaged the whole time.

How Diabetes Actually Damages Your Blood Vessels

First, a myth to clear up. Sugar does not turn into plaque. Glucose in your blood does not congeal or “build up” on artery walls like limescale in a kettle. That is not what happens.

Atherosclerosis is the plaque that causes heart attacks. It is built mainly from cholesterol particles, immune cells, cellular debris, fibrous tissue and calcium. These are laid down inside the wall of the artery. As the World Health Organization describes it, heart attacks and strokes are mostly caused by a blockage. And the most common reason for that blockage is a build-up of fatty deposits. They sit on the inner walls of the vessels supplying the heart or the brain.

What high glucose does is create the conditions for that plaque. It then forms faster, turns unstable, and ruptures sooner. Here is the real chain of events.

1. The lining of your arteries stops working properly

Every artery is lined with a delicate single layer of cells called the endothelium. It is not passive plumbing. It releases nitric oxide. That keeps the vessel relaxed, keeps the surface slippery, and keeps clots from sticking.

High glucose damages this layer over time. It cuts nitric oxide, and floods the cells with oxidative stress. The result is endothelial dysfunction. The artery lining is now inflamed, sticky and leaky, instead of smooth and calm. This is the first step of atherosclerosis. And it begins years before any symptom appears.

2. Sugar sticks to proteins and stiffens them

When glucose is abundant, it latches on to proteins and fats. No enzyme has to tell it to. Over time these become advanced glycation end-products (AGEs). AGEs cross-link the collagen in your artery walls. Think of it as caramelising the structural scaffolding. It makes vessels stiffer and less elastic. AGEs also bind to a cell receptor called RAGE, switching on further inflammation and oxidative stress. That is the mechanism set out in a 2022 review of advanced glycation end-products and vascular complications in type 2 diabetes. It was published in the journal Nutrients.

Crucially, AGEs also modify LDL cholesterol itself. Glycated, oxidised LDL is far more readily swallowed by immune cells in the artery wall. Those cells bloat into “foam cells”: the raw material of plaque.

3. Diabetes changes the kind of cholesterol you carry

Here the sugar problem becomes a fat problem. Malaysia’s Clinical Practice Guidelines on the Management of Dyslipidaemia describe a specific lipid pattern. It is called atherogenic dyslipidaemia: low HDL (“good”) cholesterol, raised triglycerides, and small dense LDL particles. Those small dense particles are more atherogenic. That means they are better at burrowing into artery walls and starting plaque.

The sting is in the next line. In atherogenic dyslipidaemia, the guideline notes, the LDL number itself is usually normal. The quality of the LDL is what has changed, not the quantity. And the guideline is clear on one more point. When a patient shows high triglycerides with low HDL, insulin resistance states such as type 2 diabetes and metabolic syndrome must be considered as the cause.

This is why doctors treat cholesterol hard in diabetes, even when the numbers look normal. In the Malaysian risk classification, having diabetes already puts you in the high or very high cardiovascular risk category. You sit alongside people who have established heart disease or chronic kidney disease.

4. Insulin resistance, inflammation and pressure

Insulin resistance is the engine of type 2 diabetes, and it does not only raise glucose. It raises blood pressure. It sustains a low-grade inflammatory state. And it makes blood more prone to clotting. It also travels with obesity, and with the same small-dense-LDL pattern described above. That is why these problems so rarely arrive one at a time.

Put it all together: a damaged artery lining, stiffened walls, nastier cholesterol, chronic inflammation, higher pressure and stickier blood. Plaque forms faster. And when it ruptures, the clot on top is bigger. It is also more likely to block the artery for good. That is a heart attack. The Ministry of Health’s Type 2 Diabetes CPG puts the conclusion in six words: “T2DM is a CVD defining disease.”

So How Much Does It Raise Your Risk?

Wildly different numbers get quoted online. Here is what the evidence actually supports:

• The International Diabetes Federation states that people with diabetes are two to four times more likely than others to develop cardiovascular disease. It adds that cardiovascular disease remains the most common cause of death in people with diabetes.
• Malaysia’s own Clinical Practice Guidelines on the Primary and Secondary Prevention of Cardiovascular Disease are issued by the Ministry of Health. They come with the National Heart Association of Malaysia and the Academy of Medicine Malaysia. They put it in outcome terms: more than 70% of patients with type 2 diabetes died of cardiovascular causes..
• The same guideline adds a detail worth knowing if you have lived with diabetes for a long time. In people who have had diabetes for more than 10 years, the cardiovascular risk is similar to that of someone who has already had a heart attack.
• It also notes a gender gap that gets very little attention: women with diabetes are 44% more likely to develop coronary heart disease than men with diabetes..

The honest summary, then, is at least double the risk, and by some measures considerably more. The risk rises the longer you have had diabetes, and the more other risk factors stack up. Malaysian death data echoes the point about age. Look at DOSM’s 2024 figures. Among Malaysians aged 41 to 59, ischaemic heart disease was already the leading cause of death, at 17.6% (5,380 deaths). This is not a disease that waits for retirement.

The Silent Heart Attack: Diabetes Can Steal Your Warning

This may be the most important section on this page.

Chest pain during a heart attack is a warning signal carried by nerves. Diabetes damages nerves. That includes the autonomic nerves supplying the heart, a complication called cardiac autonomic neuropathy. When those nerves are impaired, the pain signal can be blunted. It can also be absent altogether.

The result is silent myocardial ischaemia. The heart muscle is starved of blood. Damage is being done. But the person feels little or nothing. Malaysia’s Clinical Practice Guidelines on Stable Coronary Artery Disease (2nd Edition) state it directly. Myocardial ischaemia may occur in the absence of chest pain. It may also occur with atypical symptoms. These include breathlessness, unexplained sweating, extreme fatigue, or pain somewhere other than the chest. And the guideline names exactly who this happens to: diabetics, the elderly and women. A 2025 review of cardiac autonomic neuropathy in diabetes was published in the Journal of Clinical Medicine. It describes silent ischaemia as the most common clinical sign of cardiac autonomic neuropathy when coronary artery disease is present.

So do not treat “I have no chest pain” as reassurance. Take atypical symptoms seriously. Watch for unusual breathlessness, unexplained fatigue, sudden sweating, nausea, jaw or arm discomfort. And this is exactly why regular heart screening matters more if you have diabetes, not less. You cannot rely on your body to sound the alarm.

Risk Factors: What Makes Heart Disease More Likely

These are not symptoms. You cannot feel them. They are the conditions and habits that raise the odds. They are drawn from the risk factors in two guidelines. Those are the Ministry of Health’s Type 2 Diabetes CPG and its cardiovascular prevention guideline.

Risk factor	Can you change it?
Long duration of diabetes	No, but control from today still helps
Poorly controlled blood glucose (high HbA1c)	Yes
High blood pressure	Yes
High LDL / high triglycerides / low HDL	Yes
Smoking (including e-cigarettes)	Yes
Overweight, obesity, excess belly fat	Yes
Physical inactivity	Yes
Chronic kidney disease	Partly (it can be slowed)
Family history of early heart disease	No, but it should raise your vigilance

On that last row, the Malaysian prevention guideline is specific about what “early” means. Take heart disease or stroke in a parent or sibling, before the age of 55 in men, or 65 in women. That counts as an independent risk factor in its own right. The younger the relative was, the stronger the signal. And the excess risk persists even in people who are referred and treated early. So tell your doctor about it, rather than assuming it has been cancelled out.

Symptoms: What Your Body May Be Telling You

These are different. These are things you can actually notice. The International Diabetes Federation lists the following as signs of cardiovascular disease. In someone with diabetes, they should prompt a visit to a healthcare professional, rather than a wait-and-see:

• Chest pain, pressure, tightness or fullness (angina), often mistaken for indigestion.
• Discomfort in one or both arms, the back, neck, jaw, throat or upper abdomen.
• Shortness of breath, especially on mild exertion or when lying flat.
• Unusual fatigue or weakness that is new for you.
• Weakness or numbness in the arms or legs.
• Swelling of the feet and ankles, a sign of heart failure.
• A fast or irregular heartbeat.
• Light-headedness or fainting.

For a fuller walk-through, see our guide to the 10 early warning signs your heart might be in trouble.

When to Call 999 Immediately

Do not drive yourself. Do not wait to see if it passes. In Malaysia, call 999 now if you or someone with you has:

• Chest pain, pressure or tightness lasting more than a few minutes, or that goes away and comes back.
• Pain spreading to the arm(s), shoulder, back, neck or jaw.
• Sudden severe shortness of breath.
• Cold sweat with nausea, vomiting or light-headedness.
• Sudden weakness or numbness on one side of the face, arm or leg; sudden confusion or slurred speech; sudden loss of balance or vision (signs of stroke).

Treatment works best when given immediately. Every minute of delay costs heart muscle or brain tissue. That tissue does not grow back. And remember: if you have diabetes, the chest pain may be quiet or missing entirely. Trust the other symptoms.

What You Can Do: Your A, B and C

Protecting a diabetic heart comes down to three numbers and one habit. Your doctor is already tracking all four. The targets below are the ones used in Malaysian practice. They are taken from the Ministry of Health’s Clinical Practice Guidelines on the Management of Type 2 Diabetes Mellitus (6th Edition).

	What it means	Malaysian CPG target
A	HbA1c: average glucose over ~3 months	<7.0% for most adults; ≤6.5% if young, newly diagnosed and uncomplicated; 7.1–8.0% may suit the elderly or those at risk of hypoglycaemia
B	Blood pressure	130–139 / 70–79 mmHg
C	Cholesterol	LDL-C ≤2.6 mmol/L (moderate risk), <1.8 (high risk), <1.4 (very high risk). Triglycerides ≤1.7 mmol/L. HDL-C >1.0 (men) / >1.2 (women)
S	Stop smoking	Zero. Smoking and diabetes both narrow blood vessels, and together they compound

The same Malaysian guideline adds two lifestyle targets that are fully within your control. The first is 150 minutes of moderate exercise a week. The second, if you are overweight or obese, is up to 10% weight loss over six months. Neither requires a gym membership.

On the plate, the CPG flags low glycaemic index foods in the Malaysian context. Excessive post-meal glucose spikes are so often seen here. So swap white rice for brown, or shrink the portion at a nasi lemak breakfast. That is a real intervention, not a token one. Our guides to foods that help prevent heart disease and how much salt, sugar and fat is too much go into the practical detail.

The Medicines That Now Protect the Heart, Not Just the Sugar

For decades, diabetes drugs were judged on one thing: how much they lowered glucose. Then a series of large cardiovascular outcome trials changed the picture. A review in Diabetes Care summarised two of them. They were the landmark EMPA-REG OUTCOME trial (empagliflozin, an SGLT2 inhibitor) and the LEADER trial (liraglutide, a GLP-1 receptor agonist). The review concluded that both drugs “significantly reduced the risk of MACE [major adverse cardiovascular events], mortality from CV causes, and mortality from any cause when compared with placebo.” Strikingly, the benefit was out of proportion to the small differences in glucose control. These drugs appear to protect the heart through mechanisms beyond simply lowering sugar.

Malaysia’s Type 2 Diabetes CPG reflects this. It states that recent trials have proven two classes of glucose-lowering agents, GLP-1 receptor agonists and SGLT2 inhibitors, significantly reduce major cardiovascular events. That holds in people with established cardiovascular disease or high cardiovascular risk, “beyond their glucose-lowering effects.”

Two caveats, in the guideline’s own framing. These are prescription decisions for your doctor. They are based on your kidney function, cardiovascular risk category and other medicines. They are not something to request off a blog. And the CPG is candid that “the newer therapeutic agents are expensive, and may not be affordable to many”. For those people, reaching the HbA1c target with established medicines remains an important and effective goal.

What it does mean is that one question is now fair at your next visit: “Given my heart risk, is there a diabetes medicine that would also protect my heart?”

Get Screened, Especially If You Feel Fine

The Ministry of Health’s Type 2 Diabetes CPG recommends risk-based diabetes screening for adults over 30. It should be repeated once a year. If you already have diabetes, the same guideline asks for more. It asks for blood pressure and weight at every visit, and HbA1c every three months. It also asks for a lipid profile, a kidney function test and an ECG at least annually. Heart disease so often develops silently in diabetes. So that annual ECG is not a formality. It is your substitute for the warning system your nerves may no longer provide.

The Bottom Line

Diabetes multiplies your risk of heart disease and stroke. The International Diabetes Federation puts it at two to four times. And Malaysia’s own cardiovascular guideline records that more than 70% of people with type 2 diabetes died of cardiovascular causes. This is not because sugar clogs your arteries. It is because sustained high glucose injures the lining of your blood vessels. It stiffens them with glycation. It worsens the quality of your cholesterol. And it keeps your body inflamed. NHMS 2023 found one in six adults has diabetes, and DOSM ranks ischaemic heart disease as the number one killer. In Malaysia, this is not an abstract risk.

But every link in that chain is treatable. Know your A, B and C. Get your annual ECG. Walk after dinner. Ask your doctor about the heart-protective medicines. And if the warning signs come, even quietly, even without pain, call 999.

For more on protecting your cardiovascular health, browse our full heart health section.