Can you predict your risk of diabetes and heart attack? A simple test tells you when to take statins

Dr V Mohan, who is one of the authors of the paper, says that a simple indicator of insulin resistance such as the TyG can help in identifying those at the highest risk and focussing interventions on them.

What is the TyG index and how do we measure insulin resistance at the moment?

This is a relatively new index. We know that triglyceride and glucose are important indices independently, but someone found out that if we divide the triglyceride by glucose, you get a very good indicator of insulin resistance.

Insulin resistance, which we already know leads to diabetes, heart attack and fatty liver, is actually very difficult to measure. Right now, we measure it using a method called HOMA IR based on fasting insulin and fasting glucose levels. The first problem is that insulin is an expensive assay. Number two, you cannot measure the insulin if the person is already on insulin. This is useful for epidemiological studies.

But the gold standard is a very sophisticated Clamp study where the person goes without food for about three to six hours before and then infuses glucose and insulin during the course of the test. This is an invasive test, requiring the patient to be in a hospital for a day, and, therefore, can be done in maybe three or four persons but not at a population level. A large amount of blood is also required for this test, so it is done only by some big research centres.

So, we have been looking for simpler markers of insulin resistance. As it turned out, simply dividing triglyceride by glucose – both the tests are inexpensive and routinely done in every lab – is a very good index of insulin resistance.

And now in our PURE study, we have shown that using this simple index we could predict how those with a high TyG had a higher risk of not only diabetes but also heart disease in the future. In low and middle income countries, we actually co-related the index to cardiovascular mortality and found that those with high TyG died earlier.

Those who have high waist circumference will also have high triglyceride levels, so in a way, it is also a marker of central obesity.

How will using a measurement like TyG change the treatment protocols?

The treatment remains the same but now we can predict who needs it the most. For example, if you see 100 people in your clinic, who will you treat more aggressively? Who will you give the statins to? When you have limited funds, you can figure out who you should give the statins and aspirin to.

Not just the treatment, the preventive steps will also be focussed on those who we know to be at a higher risk of diabetes, heart diseases and strokes. You have to tell them that they have insulin resistance and counsel them to lose weight, put them on a more stringent diet, reduce their carbohydrate intake, exercise more, sleep better and have a more frequent follow-up.

Focussing the interventions on those at the highest risk is likely to reduce mortality. And the TyG measurement is simple and easily do-able in a population.

Dr V Mohan

LDL or bad cholesterol is considered to be a bigger contributor to heart diseases. Why are we then focussing on triglycerides?

See this ratio is just for prediction. Those with a high level of triglycerides are likely to have a high level of LDL as well. And, then we bring in the glucose to calculate a ratio. The ratio provides us more information and identifies the high risk better. This does not undermine the importance of LDL; it is true that in patients at risk, you have to treat the LDL first with statins.

Now that we have a simple measurement for risk of several non-communicable diseases, can it be used in screening populations at the primary care level?

It is a simple measurement that can be done in any lab. It can be easily implemented anywhere. The interventions remain the same, but when we talk about India with 1.4 billion people, the question is who do you help first; everything is a challenge. This helps us in triaging.

If you see, the co-relation of the TyG index is more pronounced in low and middle income countries. This is because rates of diabetes and heart disease are controlled in the high income countries as they have free healthcare or insurance-covered access to medicines. And, even when they do have a heart attack, they survive because an ambulance will take you to a hospital within ten minutes and they will do a stenting on the patient and administer anti-coagulants.

Here, there will be a delay in getting the ambulance, reaching a far off hospital and still finding the OT occupied – so it will take longer to receive the care. Therefore, the mortality is more in low income countries. Of course, some states do better than others but it is a challenge.

It is easy to say provide healthcare to all but it is difficult. This measure helps us in identifying those at the highest risk of developing the disease and focussing interventions on them to prevent the incident altogether.

Why Dr Mohan? Dr Mohan is a renowned diabetologist and the chairman of Dr Mohan’s Diabetes Specialities Centre. He is also the president of the Madras Diabetes Research Foundation, which is an ICMR-advanced centre for studying the genomics of Type-2 diabetes. He has over 1,500 publications. He has also received the highest honour for doctors in India, the Dr BC Roy Award, and the fourth-highest civilian award Padma Shri.