A recent study published in The Lancet has been reported (by the journal) as providing conclusive proof that statins are safe and effective in the long-term. The Lancet also produced a podcast on their website and published a commentary to accompany the study.
The results of this study, along with the associated podcast and commentary have been presented in a way that is extremely favourable to statins. However, there is an obvious fundamental flaw with this study that, in my opinion, has not been adequately discussed.
The new study relates to a follow-up of the Heart Protection Study (HPS), which was a statin clinical trial that ran for just over 5 years. At the end of this study the researchers continued to monitor the participants for a further 5 years.
During the follow-up period, increasing numbers of people who were in the original placebo group started to take a statin. By the end of the study, the number of people taking a statin in each group was the same.
The table below shows how many people (as a percentage) were taking a statin in each group.
Obviously, the study was no longer comparing a statin against a placebo – it was comparing statins against statins. Just to make it even more confusing; we do not even know which statin people took during the follow-up period and at what dosage.
This did not stop the researchers describing the results of this study as definitive evidence in favour of statins.
Most doctors who prescribe statins will not have the time to read the full study and will have to rely on the summary and the podcast. This will leave them with an interpretation of these results that is heavily skewed in favour of statins.
As far as I am concerned, the fact that just as many people in the placebo group took a statin is enough to nullify this study. However, there are several additional issues.
All of the people included in this study are categorised as having very high risk. Almost half had already had a heart attack, and everyone else had either other forms of cardiovascular disease or conditions that would place them at high risk. All of the evidence from statin clinical trials has consistently shown that any 'benefit' varies greatly according to the level of risk the trial participants have. Therefore, if any statin benefits were found during this study, it is simply unthinkable to try and extrapolate this to the general population or the majority of people who take statins.
In addition, the study report and commentary describe the results in terms of relative percentages. This is a very common problem with statin clinical trials. The relative percentage is meaningless to patients and it grossly exaggerates any suggested 'benefit'. For example, in terms of vascular related deaths a risk reduction of 18% is quoted for the initial trial period. However, the real risk reduction in absolute terms was 1.7%.
Incidently, this 1.7% risk reduction in vascular related deaths reduced to 0.1% during the follow-up period. Therefore, there is not any real evidence to support the claim that the 'benefits' of statins increase if a person starts taking the statin earlier in life.
It is also worth mentioning that statins have a wide range of adverse effects (some very serious) that were not included in this study.
Heart Protection Study Collaborative Group. Effects on 11-year mortality and morbidity of lowering LDL cholesterol with simvastatin for about 5 years in 20 536 high-risk individuals: a randomised controlled trial. ; published online Nov 23.