Tuesday 18 June 2019

'Statins have saved countless lives'

The 'blockbuster drug' has had a bad rap recently, but statins are an essential tool in the fight against cholesterol, writes Dr Brian Higgins, Galway GP and in-house doctor with TV3

Statins help you live longer, avoiding a stroke or heart attack
Statins help you live longer, avoiding a stroke or heart attack
Dr Brian Higgins

There are some things out there that are good for everyone across the board: exercise, nutritious food and clean drinking water. However, there will never be a medication available that is good for everyone and is without side-effects. Statins, a medication designed to lower cholesterol, have been hailed as a wonder-drug that some have proposed should be used in everyone - but recent controversy has cast a light on those claims.

Since 1984, we have known that lowering cholesterol significantly lowers the risk of having a heart attack. Ten years later, a breakthrough Scandinavian study showed that the statin Simvastatin showed a massive (42pc) reduction in the risk of having a heart attack over a five-year period. The legend of the 'blockbuster drug' was born, and they are now one of the most widely-prescribed drugs in the developed world.

Statins interrupt the chemical pathway through which dietary fats are converted into cholesterol, or lipids, the fatty molecules that circulate in our bloodstream. They lower LDL (bad) cholesterol and triglyceride (very bad) levels, while potentially raising HDL (good) cholesterol levels.

But what is the difference between good and bad fats? In a word, stickiness. Our 'bad' cholesterols are very sticky. As they circulate in the bloodstream, these molecules "stick" to the inner lining of blood vessels. This process is accelerated by a number of factors: high blood pressure, diabetes, smoking and an underlying genetic predisposition.

Dr Brian Higgins
Dr Brian Higgins

When these molecules stick to the inner (endothelial) lining of the blood vessel, they congeal to form a plaque. Over time, without intervention, this plaque grows larger and at some point will become unstable and rupture, and all of the sticky cholesterol will leak into the blood vessel, blocking blood flow and creating a clot.

Think of pouring old cooking oil down the sink. The tissues the blood vessel were supplying, be that heart or brain, will be starved of blood and die. This is what we call a heart attack or a stroke. This process occurs everywhere in the body and is the basis of cardiovascular disease (CVD). CVD is the leading cause of death in humans.

By reducing LDL and triglyceride levels, statins reduce the concentration of circulating sticky cholesterol, thus reducing plaque formation and the resultant progression of CVD. However, this alone does not account for the 10pc reduction in mortality over five years for every 1mmol/L reduction in LDL cholesterol.

Over time, we have realised that statins have a number of other very positive physical effects on the body including the stabilisation of plaques that have already developed, while possibly having an anti-inflammatory effect, improving blood vessel function and potentially directly reducing blood-clot formation.

In principle, statins sound fantastic and they are absolutely an excellent medication that have saved countless lives. Some doctors, jokingly, have advised putting them into the water, but unfortunately medicine has never been that straightforward.

There are two main reasons why statins are not prescribed for everyone. The first is that these medications do have side-effects which can be potentially serious and, secondly, a high cholesterol level on its own does not necessarily merit treatment with medication.

Since 2014, there has been some public concern over the safety of statins. A number of research studies have shown an association between statin use and some medical issues such as cognitive decline and diabetes. The reporting and interpretation of those studies have led to many people stopping their prescriptions inappropriately.

However, an association is not a cause. CVD itself causes a type of dementia where the tiny blood vessels in the brain become blocked, resulting in atrophy of brain tissue leading to progressive memory impairment and personality changes.

As these patients all have established CVD, there is a high likelihood that they will already have been prescribed a statin. This results in an association between the prescription and the condition - but not necessarily a causal relationship.

Think of someone with greying hair; this person is more likely to use hair dye. Performing a research study on people with greying hair would show an association with going grey and hair dye, but this does not mean that hair dye is the reason people go grey - ie, it is not a cause.

The link between diabetes and statins is a little more complicated, as statins may have a small effect on insulin metabolism. This is something that has been identified in large research trials, but there has been no doubt diabetic patients still benefit hugely from statins, meaning the "cost" of a tiny increased risk in developing diabetes is miniscule in relation to the "benefit" of reduced mortality, strokes and heart attacks bestowed by statin use in the right patients.

Cost-benefit ratios are what medical treatments are really all about. For example, every time a prescription for an antibiotic is made, the risk of killing all of a hosts healthy bacteria and the risk of an anaphylactic reaction is weighed against the cost of an infection harming the body.

We call these "risks" adverse-effects and there is no medication or medical procedure without them. This holds true for statins - the most common adverse-effect, or cost, of statin use is muscle soreness, but the benefit is getting to live longer, avoiding a stroke or heart attack. Therefore, the benefits far outweigh the potential costs. Other rare adverse effects include an elevation of liver enzymes, more severe muscle inflammation and some drug interactions.

This is why it is so important that statins are prescribed appropriately, so that only the people who will have a benefit get a prescription.

So who should be on a statin? Almost anyone who has had a stroke or heart attack needs to be on a statin to reduce the risk of having another. This is called secondary prevention, stopping something from reoccurring, and is generally quite straightforward.

Disagreement tends to be around what is called primary prevention, stopping an event from happening in the first place. Some would argue that anyone over 40 should be prescribed a statin; I don't agree with this.

In my practice, I follow the NICE (National Institute for Health and Care Excellence) guidelines who advise statin therapy in anyone who has a 10pc, or greater, risk of developing CVD in the next 10 years. Risk is calculated using a simple calculator on simple blood and clinic measurements.

There are obviously some caveats to this - for example, an 85-year-old man definitely has a greater than 10pc risk of a cardiac event but that does not mean he will be getting new tablets if he is doing well. There will always be an element of tailoring around prescriptions as guidelines are, and will always be, only a guide.

The statin I generally prescribe in the first instance atorvastatin. It is cheap, very well tolerated and extensively studied. Statins were initially very expensive but, as their patents expire, price has plummeted as generic versions are released. Generic medication is just as effective as brand medication.

I may alter the dose or type of statin depending on how a patient's lipids levels change or based on their reaction to the medicine.

For the very small minority who suffer with muscle soreness, I may either reduce the dose or change to another type which generally resolves any issues.

Occasionally I may add a second lipid-lowering drug if serum levels of cholesterol and triglycerides remain high, especially in high risk groups such as diabetics, smokers and those with established cardiovascular disease or a family history of early cardiac death.

Statins are a great medication. They have undoubtedly saved many lives and in my opinion the recent controversies have been considerably overplayed.

However, no matter how beneficial statins are, they cannot substitute for healthy lifestyle habits. Every patient of mine with high cholesterol will get dietary advice and strong motivation to start exercising regularly. Heart health is about more than just a doctor writing a prescription and a patient taking a tablet.

Lifestyle changes, in my mind, will always be the priority for managing cardiovascular disease. For example, there is no tablet in the world that will increase your lifespan as much as simply stopping smoking.

When doctor prescribes you a statin, it is because they believe there is a strong possibility of you having a stroke or heart attack in the next 10 years.

So, when you are handed that prescription, ask yourself "Why am I at risk of heart disease?", and, "What else can I do to prevent it?"

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