Statins - are they worth it?
Last week, the press reported that relatives of people with familial hypercholesteraemia are not being adequately screened in the UK, despite their increased risk of heart attacks, which could be prevented by early treatment with statins. However, the more important story was about statins themselves.
Statins are the blockbuster drugs of the past two decades. After their cholesterol-lowering effect proved to be effective in preventing further heart attacks and death in coronary heart disease (CHD) patients (secondary prevention), several studies have broadened the definition of who should get statins. However, the role for statins in people with risk factors (e.g. diabetes) but no CHD (primary prevention) is far from clear, even though some people are talking about putting statins in the water. A recent study combined data from randomised controlled trials of statins to look at over 70 000 patients without CHD, but with risk factors. They report that statin use led to a 12% reduction in death, a 30% reduction in heart attacks, a 20% reduction in stroke, and no increased risk of cancer. The effects were regardless of age, sex or diabetes. Can we now say that all patients with risk factors for CHD should get statins?
The answer is unfortunately no because we are not told properly about risks, safety and cost-effectiveness. Although the death rate dropped by 12% (relative risk reduction or RRR), it actually only fell from 5.7% to 5.1% with statin therapy (a 0.6% absolute risk reduction or ARR). Bottom line- you need to treat 170 people with statins for 4 years to prevent 1 death. For heart attacks, there is a 1.2% ARR, and this means that we would have to treat 80 people with statins for 4 years to prevent 1 heart attack. For strokes, there was a 0.4% ARR, and 240 people have to be treated to prevent 1 stroke. These numbers look less impressive than the relative risk reductions and tell us more about how costly it would be to treat everybody with risk factors (but no CHD) in the population.
The study showed no increased risk of cancer with statins. The problem is that this study did not include all the trials of statins which measured cancer outcomes, such as breast cancer, and also trials have tended not to measure rates of melanoma, which is increasing worldwide. With an average of only 2 years of follow-up, it is hard for this study to make strong conclusions about the safety of stating with regard to cancer.
So interestingly, just like aspirin, it appears that primary prevention with statins is not for everybody and the risks of long-term therapy have to be weighed against the benefits. However, the benefits for people with established heart disease are beyond doubt for statins and aspirin.