When should cholesterol lowering drug Statin be ideally used to prevent a heart attack?

Should statins be given more conservatively, considering that there has been a revision of guidelines in the US? Or given that Indians are more genetically prone to cardio-vascular diseases, should we develop our own set of guidelines to minimise risks?
“Prevention of major cardiovascular events in people who haven’t had any so far but are at high future risk is important. Recent guidelines on statin use, the US Preventive Services Task Force (USPSTF), suggest a higher risk threshold (10 per cent risk of major cardiovascular events like death, heart attack and stroke) and an age over 40 years for initiation of therapy, if one of the four major risk factors co-exs. Those are high blood lipids, hypertension, diabetes or smoking, the aggravating factors present in most Indians. What the US guidelines say is that ‘the absolute benefit will not be high enough at lower risk and age levels.’ I think this differentiation is what is being misinterpreted as meaning that there has been a downgrading of the regime for statin use,” says cardiolog and president of the Public Health Foundation of India (PHFI), Dr K Srinath Reddy.

Explaining the recent guidelines, Dr Reddy says that “these have been developed from multiple perspectives related to preventive health and public health management and not just cardiological parameters. The USPSTF guidelines are a one-size fits all formula as it is geared for primary care doctors rather than being prescriptive for cardiologs.”
“But remember that guidelines from the American College of Cardiology and American Heart Association use more elaborate risk profiling and a lower risk threshold of 7.5 per cent while permitting statin use in younger persons with high levels of risk factors like LDL cholesterol. In fact, the American Heart Association at one time had argued for an even lower risk threshold of five per cent and not wait for people to jump into the high risk bracket,” he adds.
The problem with India, says Dr Reddy, is that there are no India-specific risk assessments based on clinical trials. “In the absence of such profiling, we tend to rely on US guidelines. Our risk factors are heightened. For example, so many Indians are pre-diabetic and exhibit all the triggers that have been led earlier than usual. In fact, diet, exercise and smoking cessation should be the approach to reduce the risk in all while moderate statin therapy should be initiated in those identified as persons at high risk. There is no point in waiting for elevated risk factors,” he adds.
Evidence published in the journal The Lancet in 2010 had shown that reducing low-density lipoprotein cholesterol 1mmol/L with statins reduces the risks of ischaemic heart disease and stroke 24 per cent to 25 per cent. Statins reduce the risk of cardiovascular disease lowering the level of low-density lipoprotein (LDL) cholesterol in the blood. This forms plaques and narrows the diameter of blood vessels. Over time, this narrowing can block blood flow to certain organs. If blood flow to the heart is blocked, it can cause a heart attack, and if it occurs in the brain, it can cause an ischaemic stroke.
The latest round of US guidelines say that statin use would yield moderate benefit for those aged between 40 and 75 with one or more factors that could increase the risk of cardiovascular disease, no hory of cardiovascular disease, and an estimated 10-year cardiovascular event risk of 10 per cent or greater. Those of the same age with the same risk factors with a 10-year cardiovascular event risk factor of 7.5 per cent to 10 per cent will have a small net benefit from taking statins.
However, there was not enough evidence to determine whether it’s beneficial to initiate statin use in those older than 75.