One problem with all the trials of statins is that they look at the probability of still being alive after x years. But that’s not really the question patients want answered. Patients want to know how much longer they can expect to live if they take a statin every day for the rest of their lives. Is it weeks? months? years? decades?
Considering that statins do have known side effects, with muscle pain being the most common and widely recognized, and considering that many people think it’s annoying to have to take a pill every day, they generally want to know the size of the benefit before they decide whether to take the drug or not. Unfortunately, the answer to that question is hard to extrapolate from the studies, due to the way in which they have been designed. Saying that a drug decreases your risk of dying by x over five years doesn’t really tell you anything about how much longer you can actually expect to live.
In 2015, a group of researchers looked at the data from the statin trials and re-calculated the effect in terms of increased longevity. The study was published in the British Medical Journal, and it was funded by the University of Southern Denmark. One of the authors had significant conflicts of interest, having received money from multiple different pharmaceutical companies that produce statins.
All randomized trials comparing statins to placebo, and that also fulfilled the following three criteria, were included: They had to have at least 1,000 participants, they had to follow patients for at least two years, and they had to provide a survival curve. The reason a survival curve was necessary was because the increase in longevity was extrapolated by calculating the area between the survival curves for the statin group and the placebo group. I think the other two criteria are also reasonable – statin studies looking at mortality with less than 1,000 participants and that don’t even follow patients for two years are leaving too much up to chance.
The authors identified eleven studies that fulfilled the criteria, of which six were investigating statins for primary prevention (i.e. to treat people without known atherosclerotic disease) and five were investigating statins for secondary prevention (i.e. to treat people who had already had heart attacks, or in some other way clearly manifested atherosclerotic disease). These eleven studies together included a total of 92,135 patients, so the data are robust. Participants in the studies were followed for between two and six years. Most of the major statin trials (4S, WOSCOPS, ALLHAT, LIPID, ASCOT-LLA, JUPITER) were included in the analysis.
So what were the results?
Life was prolonged by between -5 and 19 days in the primary prevention trials (yes, that’s -5, as in minus five. In one of the studies people taking a statin lived five days shorter than people taking a placebo). In the secondary prevention trials life was prolonged by between -10 and 27 days (yes, again that’s -10, as in minus ten).
When everything is averaged out, people taking a statin for primary prevention lived three days longer than people in the placebo group. People taking a statin for secondary prevention lived four days longer than people in the placebo group. The average follow-up period in these studies was around four years, so if you assume that statins have a linear life-prolonging effect that grows with time (rather than petering off after a while, which is likely), then you can expect to live around one day longer for each year of treatment.
Huh? That’s disappointing. You take a drug dutifully, which your doctor has told you is vitally important, and it prolongs your life by mere days. The results are especially disappointing when you consider that most of the eleven trials were industry funded, and industry funded trials usually show better results than are seen in the real world. So most likely the real world benefit is even smaller than the tiny benefit found in these trials.
And remember, this analysis was done by people with financial ties to the pharmaceutical industry. If even people who are friendly with industry say that statins only prolong life by mere days, we can probably trust that the benefit really is that tiny.
As mentioned at the beginning of the article, statins are not completely free of side effects. So even if you are willing to take a drug every day that has an extremely marginal effect on longevity, then that benefit needs to be weighed against the risk of side effects.