There has been much discussion over the last few days, by journalists and health professionals, on the new guidelines for the treatment of blood cholesterol put forward by the American Heart Association and the American College of Cardiology. Critics have raised concerns the revised guidelines will increase the number of healthy people who take statin drugs by 70 per cent, that treatment thresholds are too low and that some guideline writers have links to the drug industry.
But these discussions have largely missed two key words in the new guidelines: "patient preference." The ACC/AHA state clearly, and emphatically -- the term is used more than 20 times in the document -- this is a framework for clinical decision-making that must incorporate "patient preferences." To put this into context, the Canadian Cardiovascular Society lipid guidelines from 2006 and 2009 make no mention of patient preferences whatsoever, and while their 2012 version contains the word "preferences" five times, only once do they actually refer to patient preferences.
This is an important transformation in guideline attitude, and here's why. No matter what recommendations this guideline or a health care professional may make, the patient is the one who should decide what's best.
The biggest limitation of the ACC/AHA guidelines is that they don't provide information in a manner that easily facilitates a balanced discussion between a patient and a health care professional. Fortunately, it's not all that difficult.
One of the most controversial parts of the guidelines is the threshold for treatment they recommended -- individuals with a 10-year heart attack and stroke risk of 7.5 per cent or greater is where "risk reduction benefit clearly exceeds the potential for adverse effects." That's their opinion but what counts is your opinion.
The evidence suggests statins reduce heart attack/stroke risk by approximately 30 per cent.
What does this mean? If you take roughly a third off of 7.5 per cent (2.5 per cent), the risk for heart attack and stroke would drop to around five per cent. Put a different way, this means 40 people need to be treated for 10 years to benefit one person; 97.5 per cent get no clinical benefit whatsoever from statin drugs.
Let's say a higher threshold like 10 per cent had been chosen instead, as some critics have argued should have been the case. Doing similar math, 10 per cent goes down to seven per cent (a 30 per cent reduction), which is a difference of three per cent. Thus, 33 people need to be treated to benefit one person and 97 per cent get no benefit from taking statins. So the big debate about the threshold is a debate about a 0.5 per cent 10-year difference (a three per cent vs. a 2.5 per cent benefit).
Now, on the other end of the risk spectrum, a person with a past stroke/heart attack or an older person with many risk factors, may have roughly a 30 per cent risk. They would get a 10 per cent absolute benefit over 10 years. This means this higher risk person (who has already had a heart attack or stroke) taking a statin for 10 years has about a one in 10 chance of benefiting from the medicine, while 90 per cent will get no benefit at all.
That's the benefit, so what about harm?
Muscle aches and stiffness occur in five to 10 per cent of people taking statins, with severe muscle or kidney damage occurring in roughly one in 10,000, and possible abnormal liver lab values in two per cent. Some people experience nausea, constipation, diarrhea and then, of course, there is the drug cost and the bother of taking a pill every day. Fortunately, most of these harms are reversible.
There are a few caveats. Most studies with statins have been for five years or less, so we really don't know about long-term benefit and harm. You may have also heard statins cause diabetes, but the risk increase for diabetes is only about one per cent, and because statins overall reduce the risk for heart attack or stroke (the reason we treat type 2 diabetes), this risk is not clinically important.
If, after thinking about the above information you wish to try a statin, then that is the right choice for you. If, however, you don't want to take a statin based on the information, that is also the right choice for you. In either case, you can always change your mind.
Your health care professional should support you no matter the decision. This is really what the new guidelines should be all about.
James McCormack, an expert adviser with EvidenceNetwork.ca, is a professor with the faculty of pharmaceutical sciences at the University of British Columbia. Mike Allan, a family doctor, is director of evidence-based medicine in the department of family practice at the University of Alberta.