83 for mortality
The numbers presented are from the best studies that are currently available. Some of these studies will NEVER be repeated and so this is all we'll ever have to go on. There will be continued study in some areas and we aim to incorporate this forward into our site. We're constantly monitoring the literature for updates (if you think there is something we've missed, email us!). The conclusions we draw are a best estimate, folks. We've presented what we think is the closest thing to the truth about this intervention, but our data is only as good as the studies that underlie it — and often, the studies aren't as complete or as good as we'd like. We present one number here for the NNT, but please realize this is an estimate and there is a range for what this intervention can offer a given person. That range will depend upon the person's spectrum of disease (mild/moderate/severe), their demographic, their subtype of disease, the setting of the intervention, their general health, and literally thousands of other variables. Using these numbers in practice means taking a number of large leaps about all of these variables, and also about the veracity of the underlying research. Therefore, as with any 'high quality' data, the application of data requires a doctor's expertise and deliberate consideration.
In Summary, for those who took the statin for 5 years:
- 96% saw no benefit
- 1.2% were helped by being saved from death
- 2.6% were helped by preventing a repeat heart attack
- 0.8% were helped by preventing a stroke
- 0.6% were harmed by developing diabetes*
In Other Words:
- 1 in 83 were helped (life saved)
- 1 in 39 were helped (preventing non-fatal heart attack)
- 1 in 125 were helped (preventing stroke)
- 1 in 167 were harmed (develop diabetes*)
Where We Get The Numbers:
Source: Thavendiranathan P. Primary prevention of cardiovascular disease with statin therapy. Arch Int Med. 2006; 166: 2307-13.
CTT Collaborators. Efficacy and safety of cholesterol-lowering treatment: prospective meta-analysis of data from 90 056 participants in 14 randomised trials of statins. Lancet. 2005; 366: 1267-1278.
Ridker et al. Rosuvastatin to prevent vascular events in men and women with elevated c-reactive protein. NEJM. 2008; 359(21): 2195-2207.
Efficacy Endpoints: Death, heart attacks, strokes
Harm Endpoints: Rhabdomyolysis (muscle breakdown), cancer, diabetes
Narrative: Statin medications are aimed at an enzyme in the cholesterol production pathway, and are therefore intended to reduce cholesterol. In some patients elevated cholesterol plays a role in the development of coronary artery disease and heart attacks, so the drugs are intended to reduce the chance of death by reducing heart attacks and strokes.
These data examine the effect of statins for people who have known heart disease or a history of stroke. The effectiveness of the statins is fairly consistent across studies in this group—they lower cholesterol in most people who took them. A few people will also avoid a heart attack or stroke by virtue of this change. After 5 years of daily statin therapy study subjects achieved a 1.2% lower chance of death, a 2.6% lower chance of heart attack, and a 0.8% lower chance of stroke. As a public health measure, this suggests that statins may have an identifiable effect, because while the chances of any one individual being affected are small (19 out of 20 people who took the drugs for five years saw no effect), when one million people take them roughly 45,000 people saw some benefit, while another 6,000 may see a harm.
Caveats: Virtually all of the major statin studies were paid for and conducted by their respective pharmaceutical company. A long history of misrepresentation of data and occasionally fraudulent reporting of data suggests that these results are often much more optimistic than subsequent data produced by researchers and parties that do not have a financial stake in the results. These additional studies may however take years. Also, harm from these drugs is difficult to predict, partly because harms are often difficult to anticipate and are often poorly tracked. Such findings often come up years after new drugs have been on the market.
*The development of diabetes is one such unanticipated harm found in a recent large study and it seems likely therefore that this applies to the data above, although this is a best guess.
Author: David Newman, MD
Published/Updated: June 3, 2010
