Heart attack risk - how do you know?

On the one hand, nobody in their right mind wants to have a heart attack, especially an unnecessary one. On the other hand, we've seen a real backlash against the idea of us becoming a nation of pill-poppers. So I spend as many consultations pushing back against patients desperate for tablets to reduce their risk of heart attacks as trying to persuade people they really could increase their chances of a long and healthy life by taking high blood pressure medicine regularly.

To treat or not to treat?

I can see both sides of the drug/drug free argument - and again it depends where you lie on the risk spectrum. People who've already suffered a heart attack or stroke, and those with type 2 diabetes and other heart attack risk factors lie at one end.

No contest - yes. If you've had a heart attack or stroke, the evidence is so strong that I've never met a doctor who argues against preventive medication. Taking a cholesterol-lowering statin (1) dramatically reduces the chance of a second event - with every 1 mmol/litre reduction in 'bad' LDL cholesterol cutting your risk by about 20%, even if your cholesterol is already fairly low (2). Likewise, if you've had a heart attack or stroke, getting the upper reading of your blood pressure down by just 5 mmHg can cut your risk of stroke by 14% if it's high (3).

No contest - no At the other end of the spectrum is the barn door paragon of virtue - young, eats raw kale by the fistful, funs 10 miles before breakfast, all their relatives live to 100. Their risk of having a heart attack is way under 1% over 10 years - which means that even if we cut it by a quarter the change in their odds would be minimal.

Here's the tricky bit: But what about the ones in the middle? If your risk of heart attack or stroke is under 10% in the next ten years, you're considered low risk. If it's over 20%, you're 'high risk'. It's an arbitrary cut-off point, but it means at least 1 in 5 people like you will be struck down if we don't act. It also means you're highly unlikely ever to get yourself into the low risk category, no matter how much you improve your lifestyle. Statistically, if your risk of heart attack or stroke is 10-20%, you lie in a grey area. I'd love to prescribe fewer tablets, and I do everything I can to help people in this category make lifestyle changes that mean they don't need them. For instance, if you're obese and lose 10kg (about 1 ½ stone or 22lb), you can:

  • Cut your total cholesterol by 10%
  • Reduce your LDL cholesterol by 15%
  • Raise your 'good' HDL cholesterol by 8%
  • Cut the amount of toxic 'intra-abdominal fat' inside your stomach by 40%
  • Drop your average fasting blood sugar by 50% if you have diabetes
  • Cut your risk of dying by 20%
  • Lower your blood pressure by about as much as a blood-pressure lowering tablet (4).

Of course, not everyone manages to eat more healthily, exercise regularly and give up smoking. For them, the discussion is likely to change sooner or later to preventive tablets - for every 25 people with a 20% risk treated for 10 years with a statin, we could prevent one heart attack or stroke (2). But first we have to identify who's really at risk.

How do we assess risk?

Assessing risk is a complicated old business. Some risk factors are obvious - if you quit smoking, you'll drop your risk of heart attack, end of. But even there, it can be hugely complicated to work out how much benefit you actually get - we need studies involving many thousands of people. The same applies to blood pressure, cholesterol, getting older - the higher the figure, the higher the risk.

But lots of other factors play a part too, which is why the calculators used to assess your risk have been evolving. The QRisk and more recently QRisk 2 calculators have been routinely used by GPs across the UK to tease out a single risk figure for the last few years. They take into account a host of factors that can influence your risk of heart disease:

The new kid-calculator on the block

As of this month, a new-and-improved version of the calculator - Qrisk3 - is being rolled out. And some of the risk factors they've identified might surprise you. They include:

If you've had your risk assessed and don't have any of these conditions, you don't need to worry. But if you've previously been given the all clear, look at the list above. If you have one of these conditions, it could just mean your risk of heart disease has been underestimated. That may not mean you need medicine - but it's certainly worth checking out

References:

1) MRC/BHF Heart Protection Study Collaboration Group. Effects of simvastatin 40mg daily on muscle and liver adverse effects in a 5-year randomized placebo-controlled trial in 20,536 high-risk people. BMC Clin Pharmacol 2009;9:6. http://dx.doi.org/10.1186/1472-6904-9-6

2) Cholesterol treatment triallists' collaboration. Lancet. Aug 11, 2012; 380(9841): 581-590.

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3437972/

3) JAMA 2002;288:1882-1888

4) Betteridge DJ and Morrell JM Clinicians' Guide to Lipids and Coronary Heart Disease Second Edition Arnold, London 2003 p173

Disclaimer: This article is for information only and should not be used for the diagnosis or treatment of medical conditions. Patient Platform Limited has used all reasonable care in compiling the information but make no warranty as to its accuracy. Consult a doctor or other health care professional for diagnosis and treatment of medical conditions. For details see our conditions.



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