Tuesday, July 6, 2010

Statins and scientific integrity

“Statins” are a class of drugs that lower lipid levels, especially low-density lipoproteins (LDL, “bad” cholesterol), and raise high-density lipoproteins (HDL, “good” cholesterol). Since we know elevated LDL levels are associated with higher risk for a number of vascular diseases, mainly coronary heart disease but also stroke, it made sense that these drugs would be beneficial for preventing recurrences in people who had prior heart attacks and strokes (“secondary prevention”) as well as preventing a first attack in those who had the risk factor of elevated LDL (“primary prevention”). Indeed, studies have shown the former; that is, that the use of statins reduced the risk of both a second attack and dying. However, most of the studies that have been done, and showed benefit, studied both groups, people who had already had a coronary event and those with elevated LDL who had not, and combined the results. The first big study that presumed to show benefit of these drugs for primary prevention was the JUPITER study (“Justification for the Use of Statins in Primary Prevention” – all these studies have cute, if often tortured, eponyms). It specifically looked at the drug rosuvastatin, marked as Crestor ® by its manufacturer, AstraZeneca, who also happened to fund the JUPITER trial.

Two articles that just appeared in the Archives of Internal Medicine (V 170, #2, June 28, 2010) raise serious questions about the use of statins for primary prevention. But they also raise serious questions about research ethics, particularly when trials are industry funded, and the strategic manipulation (not falsification) of the data that is presented to make drug therapy look better – this can mean billions of dollars in sales for the manufacturer. They also point out the danger of looking at intermediate, or “surrogate”, outcomes (in this case, lowered cholesterol and LDL) rather than the ones of real interest to patients, which are, essentially, death (mortality) and the quality of life (morbidity). I have discussed this previously (“Quality and Chronic Disease Management,” Feb 24, 2009, and “Physician conflict of interest” Dec 8, 2008; see also the article by GY Gandhi, et. al., “Patient-important outcomes in registered diabetes trials”, JAMA. 2008 Jun 4;299(21):2543-9.)

The first article, “Statins and all-cause mortality in high-risk primary prevention”, by KK Ray, et. al. (Arch Int Med, 28 Jun 2010; 170(12):1024-31) is a “meta-analysis”. This is a type of study that looks at a group of previously-done studies to try to determine if there is a consistent conclusion that is stronger because it includes more patients than any one study, or weaker because the various studies contradict each other. The authors’ goal was to tease out the results for primary prevention from studies that had looked at the use of statins for both primary and secondary prevention. There were 11 studies that met their criteria, which had a total of 65,229 (= “a lot”) of participants. Their Conclusion (verbatim from the abstract): “This literature-based meta-analysis did not find evidence for the benefit of statin therapy on all-cause mortality in a high-risk primary prevention set-up.” This is not to say that the statins did not lower LDL; they did, and significantly, but in the population of people that had not yet had a coronary event or stroke, they did not prevent mortality. It is important to note that they did also, to a small degree, decrease the risk of having a heart attack, although not of dying. The reduction in risk was about 1.5%; that is, if 200 people are treated for 5 years, 3 will not have heart attacks (NNT=67 over 5 years). The previous studies, by mixing up those who did have a prior event and did have lower mortality (secondary prevention), with those who had not, showed, on net, a benefit. This study demonstrates that there is no reduction in mortality from using statins as primary prevention; whether the small reduction in MIs and their associated morbidity and cost is worth the administration of statins in high-risk patients is at least questionable, and may be an issue for each patient to decide with their doctor.

What about the JUPITER trial? This is the subject of the second article, “Cholesterol lowering, cardiovascular diseases, and the rosuvastatin-JUPITER controversy”, by M deLorgeril et.al. (Arch Int Med 28 Jun 2010;170(12):1032-36. In a scathing “critical reappraisal” the authors note a slew of flaws in both the conduct and reporting of the JUPITER study. These include ending the study early, after only 2 years, at a time when it appeared that there was mortality benefit from the patients treated with rosuvastatin but when the curves were beginning to come together (i.e., maybe with more time the apparent benefit to rosuvastatin treatment would have disappeared and there would have turned out to be no difference in mortality rate), publishing reports in which the end of that curve was truncated, to not show the coming together, and publishing “subgroup” analyses that seemed to show benefit (by gender) but not where they didn’t (patients with diabetes). Most surprisingly, JUPITER had what seemed to be an extraordinarily low rate of fatality from myocardial infarction. The authors note that, to be able to get meaningful data to look at, they had to do calculations from the data presented by the JUPITER authors. For example, to know how many people died from heart attacks (myocardial infarction, MI) they had to subtract “nonfatal myocardial infarction” from “any myocardial infarction. This is not falsification, but it is very unusual for authors to present the data in a way that readers are required to make such calculations in order to get very important information. The rate of fatal to non-fatal MI was extremely low compared to studies from the World Health Organization, that show it to be 40-50%; in JUPITER it was 8.8% in the placebo group and 29% in the rosuvastatin group. First of all, it seems, if this data is correct, the fatal to non-fatal MI rate was 3 times as high in the group treated with rosuvastatin as in the group that was not treated (surely not the a point the authors and sponsoring company wanted to emphasize). Moreover, everyone in the study was “…unexpectedly – and inexplicably – highly resistant to acute ischemia and infarction.” The authors of this article suggest that there are many inconsistencies and implausabilities in the JUPITER data.

They then go on to discuss at length the roles of the sponsor (the drug company) and conflict of interest in reporting the data both by the sponsor and the principal investigator, who is co-holder of a patent for a test that is used to show “risk” for coronary artery disease (called “C-reactive protein, or CRP). They refer to other industry-sponsored flawed studies, including those about rofecoxib (Vioxx ®) and gabapentin (Neurontin ®), which I have discussed previously (“The ‘Neurontin Legacy’”, Jan 22, 2009). A superb editorial by Lee Green, “Cholesterol-lowering therapy for primary prevention: still much we don’t know” (Arch Int Med 28 Jun 2010; 170(12):1007-8) summarizes these issues.

Think about this. We have a bunch of studies that seem to show that statins are effective for prevention of cardiovascular events (heart attack and stroke) and prevent death. Turns out that they do this for those who have already had a heart attack, but for those who haven’t, the reduction in heart attack is small and there is no reduction in mortality. The use of statins in the much larger group, people with elevated cholesterol who have not yet had a heart attack, means big money for the drugs’ manufacturers. Studies that mixed the two groups blurred the distinction.

Then we have a big study (JUPITER) that purports to show that statins ARE effective for primary prevention, but that study is funded by the drug company and is seriously flawed. We know elevated cholesterol is associated with heart attack and we presume lowering cholesterol would help prevent those heart attacks, but, amazing and very important, when the study is actually done, the data doesn’t show it. (In studies looking at another such indicator, homocysteine, it was shown that, while elevated homocysteine levels are associated with heart attack, and folate – a cheap drug – lowers homocysteine levels, this did not decrease the rate of MIs. Too bad for the makers of the expensive homocysteine level test.)

I assume that I do not have to review the conflict of interest in the study being funded by the drug company and having the principal investigator a patent holder of a test that is highly used for assessing MI risk. The obvious concern is not that this was a potential conflict in the JUPITER study, but that it in fact led to selective interpretation and presentation of data (and the answers to how they had such a low rate of fatal MIs is still not in). This certainly challenges the claim we sometimes hear that just because there is a potential conflict of interest, it doesn’t mean that there is bad science being done. Of course, intrinsically it doesn’t, but this is one more example – with Vioxx and Neurontin and others – to show that it often does. And it also makes it harder for those who would argue that accepting industry gifts (whether lunch or fancy vacations) is benign. All these issues make a great example for teaching students, about conflict of interest, surrogate measures, scientific integrity, and how, from big issues to small ones, self interest colors our perceptions (see J Dana and G Lowenstein, “A Social Science Perspective on Gifts to Physicians From Industry”, JAMA. 2003;290:252-255).

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