Reviewed by Dr. A M Thirugnanam, MD, MSICP, FSCAI, Ph.D. — Senior Interventional Cardiologist
India has among the highest numbers of people living with diabetes anywhere in the world, and most of them will not die of diabetes itself. They will die of what diabetes does to their arteries. A person with type 2 diabetes carries roughly the cardiovascular risk of someone without diabetes who has already had a heart attack. That single fact should change how diabetes is managed — and often does not.
How high blood sugar damages arteries
Glucose is not inert. When it circulates at high concentration it attaches itself to proteins throughout the body, forming compounds that stiffen tissue and inflame the delicate single-cell lining of your arteries. That lining, the endothelium, is what keeps blood flowing smoothly and keeps cholesterol out of the artery wall.
Once it is inflamed and injured, three things happen together. LDL particles enter the wall more easily. The artery loses its ability to widen on demand, so it cannot increase blood flow when you climb stairs. And blood becomes more likely to clot. Diabetes therefore does not simply add to your risk — it multiplies the effect of every other risk factor you have.
This damage begins before diabetes is diagnosed. By the time fasting sugar crosses the diagnostic threshold, the process has typically been under way for years during the prediabetic phase.
Why it is worse in Indians
South Asians develop insulin resistance at lower body weights than other populations. A man with a body mass index of 24 — technically normal — may already have substantial visceral fat around the liver and pancreas. This is the “thin outside, fat inside” pattern, and it explains why so many slim Indian men are surprised by a diabetes diagnosis.
The practical consequence: waist circumference matters more than weight. For Indians, the thresholds are 90 cm for men and 80 cm for women — considerably lower than the figures used in Western guidelines. Measure at the navel, standing, after breathing out normally.
Your numbers
- Fasting glucose: normal below 100 mg/dL; prediabetes 100–125; diabetes 126 or above
- HbA1c: normal below 5.7%; prediabetes 5.7–6.4%; diabetes 6.5% or above
- Post-meal glucose (2 hours): normal below 140 mg/dL; diabetes 200 or above
HbA1c reflects your average blood sugar over roughly three months, which makes it far more useful than a single fasting value. But it has a blind spot: it can look acceptable while post-meal sugars are swinging high. In Indian patients eating carbohydrate-heavy meals, those post-meal spikes are common and are themselves damaging to arteries. If your HbA1c is reasonable but you feel drowsy an hour after lunch, ask for a post-meal reading.
For most adults the target is an HbA1c below 7%. If you are young, newly diagnosed and otherwise well, below 6.5% may be appropriate. If you are elderly, have advanced kidney disease or a history of dangerous low-sugar episodes, a more relaxed target of 7.5–8% is safer — driving sugar down aggressively in that group causes more harm than it prevents.
The medications that protect the heart
Not all diabetes drugs are equal from a cardiac point of view. Two classes lower blood sugar and independently reduce heart attacks, heart failure hospitalisation and kidney decline:
- SGLT2 inhibitors — empagliflozin, dapagliflozin. Particularly valuable if you have heart failure or reduced kidney function.
- GLP-1 receptor agonists — semaglutide, dulaglutide, liraglutide. These also produce meaningful weight loss.
Metformin remains a reasonable first medication, is inexpensive and is well tolerated. But if you have diabetes and established heart disease, kidney disease or heart failure, current evidence supports adding one of the two classes above regardless of what your HbA1c is doing. Many Indian patients are never offered them.
Everything else matters at least as much
Controlling sugar alone does not protect the heart nearly as much as patients expect. Large trials have shown that intensive glucose control reduces eye and kidney complications more than it reduces heart attacks. What reduces heart attacks in people with diabetes is treating the whole picture:
- LDL cholesterol driven below 70 mg/dL, or below 55 if you already have heart disease. Nearly everyone with diabetes over the age of forty should be on a statin.
- Blood pressure below 130/80.
- Complete cessation of tobacco.
- Waist reduction — a 5–7% weight loss improves sugar, pressure and lipids simultaneously.
- Regular activity — 150 minutes weekly, plus two sessions of resistance work. Muscle is where glucose is disposed of.
Silent heart attacks
Long-standing diabetes damages the nerves that carry pain signals from the heart. As a result, a significant proportion of heart attacks in people with diabetes occur without classic chest pain. Instead there may be unexplained breathlessness, sudden profound fatigue, nausea, sweating, or simply a vague sense that something is badly wrong.
If you have had diabetes for more than ten years, treat any new, unexplained breathlessness on exertion as a cardiac symptom until proven otherwise. Do not wait for chest pain that may never come.
What to ask your doctor
- What is my HbA1c, and what target are we aiming for?
- Am I on a medication that protects my heart and kidneys, not only one that lowers sugar?
- What is my LDL, and am I at the target for someone with diabetes?
- Should I have a cardiac assessment — an ECG, echocardiogram or stress test — given how long I have had diabetes?
- Has my urine been checked for protein, and my kidney function calculated?
This guide is educational and does not replace a consultation with your own doctor. Do not start, stop or change any medication based on what you read here.
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