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A recent meta-analysis published in the British Medical Journal by Bolland, et. al., finds that there is a 30% increase in the risk of myocardial infarction (MI) in women taking calcium supplements for osteoporosis (“Effect of calcium supplements on risk of myocardial infarction and cardiovascular events: meta-analysis”, BMJ 2010;341:c3691). If supported by other research, this could be big news, as millions of women are doing just that. A few “bullets”:
· 15 studies were reviewed by the meta-analysis comprising comparisons of 12,000 women either taking or not taking calcium supplementation for osteoporosis. For some of these studies results were available for individual women, and some for just the group as a whole, but the results were similar.
· Women receiving calcium had 30% more MIs than those who were not. Other end points: stroke, death from cardiovascular disease, and death overall, did not show significant differences, although they did show trends toward reduction in the non-calcium groups.
· The studies reviewed in the meta-analysis were all of women taking calcium but not taking vitamin D supplementation with it.
· The studies were not done for the purpose of looking at cardiovascular mortality; the data were re-analyzed and other sources of data were used to look at the outcome events.
The authors recommend that women who are taking calcium without vitamin D for osteoporosis stop doing so unless they are also taking a drug that treats osteoporosis, such as a bisphosphonate (which have their own risks, although in women with osteoporosis these are usually outweighed by the benefits) or selective estrogen receptor modulator (SERM) like raloxifene, usually used for breast cancer treatment (links are to a few different websites, including WebMD, FDA, and BreastCancer.org; they are representative although not definitive, and there are, of course, other sites). They note that their results are similar to other studies of women taking calcium alone, although a Women’s Health Initiative (WHI) study on women taking both calcium and vitamin D did not show any effect on the incidence of coronary artery disease. The authors suggest possible reasons for the difference, including protective effects of vitamin D, the younger age of the WHI participants (mean of 62 vs. 75 for the meta-analysis), and the interesting, but slightly confusing fact, that the WHI study had a much higher percent of women who were taking calcium before the study began (“non-protocol”): 54% vs. 1.2%. If taking calcium is associated with more MIs, why would women who were taking more calcium before the study have lower rates? And yet, the authors note that “Interestingly, the only study in our analysis that reported a relative risk of less than 1.0 for myocardial infarction with calcium also had high non-protocol use of calcium supplements.”
In their accompanying editorial, “Calcium supplements in people with osteoporosis”, BMJ 2010;341:c3856), JGF Cleland, K Witte and S Steel go farther than the authors of the meta-analysis, saying clearly in their sub-head “Should not be given without concomitant treatment for osteoporosis”, even when given with vitamin D. Their justification is the lack of good evidence for improved outcomes, including pathologic fractures, with the use of calcium and vitamin D. “Calcium supplements, given alone, improve bone mineral density, but they are ineffective in reducing the risk of fractures and might even increase risk, they might increase the risk of cardiovascular events and they do not reduce mortality. They seem to be unnecessary in adults with an adequate diet. Given the uncertain benefits of calcium supplements, any level of risk is unwarranted.” With regard to vitamin D, they say “Vitamin D supplements might reduce the risk of falls, might have important clinical effects on cardiovascular function, do not increase mortality, and may mitigate the trend to excess mortality seen with calcium supplements alone. However, no conclusive data are available to show that current doses of vitamin D supplements with or without calcium supplements reduce the rates of fracture, and meta-analyses found evidence of substantial reporting bias.”
The editorialists emphasize that while calcium does increase bone density, this is a surrogate variable while the issues of fractures and mortality are the true outcomes, an issue I have addressed several times recently (Rosiglitazone and the "Holy Grail", July 16, 2010; Statins and scientific integrity, July 6, 2010 ). They say “Surrogate measures may be useful in pilot studies but become problematic when they become the goal of treatment.” They are quite rigorous in looking and risk and benefit, noting even that exercise, while perhaps a good way to increase bone strength, “also carries risk”. They cite Kanis, et. al., from 2002[1], but it should be obvious that exercise can have risk.
The last part of the editorial is, however, more concerning to me. The authors call for greater demonstration that drugs will have positive effects on important outcome variables (a good thing) but they then worry that such requirements will be so burdensome as to stifle research: “Requiring companies to show before licensing that treatments for chronic diseases such as osteoporosis, diabetes, and hypertension reduce long term disability and death could lead to a cessation of research in these areas. The cost and commercial risk would be too high.” They then call for an extension of patents on these drugs to 50 years, similar to the Berne convention for copyrights on a song. The presumption is that this would be long enough for the companies to make back their money. Obviously, however, this also means that consumers would have to pay the higher costs for patent, rather than generic-equivalent drugs, for much longer.
Amazingly these authors, despite citing no conflicts of interests (which might explain such a position if they in fact held patents or were being paid honoraria by pharmaceutical manufacturers) dispense with such concerns in a single sentence “Lower prices for innovative drugs could be negotiated.” By whom? How? What would be the effect on the consumer? All I can imagine is that because they are British, and in Britain there is a National Health Service which charges a fixed fee to patients for all drugs, that they are thinking only of cost to the NHS and have no idea how much the cost of patented drugs is to Americans. Which, as Americans know, can be phenomenally high. (Example: generic alendronate, the oldest bisphosphonate, costs roughly $40 a month for either 35mg [recommended for prevention of osteoporosis] or 70mg [recommended for treatment of osteoporosis] per week doses, while the brand name, Fosamax ® costs about twice that; for those not available generically, risendronate (Actonel ®) costs 3 times as much, and ibandronate (Boniva ®) costs about $350 a month; all prices wholesale from ePocrates and www.drugstore.com.) Taking drugs that you need for a chronic disease is very different from downloading a song!
Of course, this is another strong argument for having a national health insurance plan that covers everyone. In the meantime, while we will wait for the certain flurry of responses and comments, not taking calcium unless one is also taking a bisphosphonate or similar osteoporosis treatment drug, seems prudent; taking vitamin D, without calcium, for its other benefits, is probably still a good idea.
[1] Kanis JA, Brazier JE, Stevenson M, Calvert NW, Lloyd JM. Treatment of established osteoporosis: a systematic review and cost-utility analysis. Health Technol Assess 2002;6:1-146.
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Showing posts with label heart attack. Show all posts
Showing posts with label heart attack. Show all posts
Monday, August 2, 2010
Tuesday, July 6, 2010
Statins and scientific integrity
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“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).
.
“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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