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Showing posts with label placebo. Show all posts
Showing posts with label placebo. Show all posts

Friday, March 14, 2014

Researchers pronouncing ‘statins are safe’ are undermined by their own observations - Briffa

Researchers pronouncing ‘statins are safe’ are undermined by their own observations

Listen to most ‘key opinion leaders’ talk about statinsand you will hear soothing reassurances about their safety. Yet, my experience as a doctor suggests that adverse effects such as fatigue and muscle pain occur more commonly than ‘official statistics’ suggest. However, a study published this week claims to provide evidence that, for the most part, statin side effects are ‘imagined’ [1].

In this research, the adverse effect rates from statins was compared with those seen in individuals taking placebo (dummy) pills in a total of 29 studies. The conclusion was that apart from increasing the risk of diabetes, statins don’t generally have any more adverse effects than placebo. The actual words the authors use in their conclusion are: “Only a small minority of symptoms reported on statins are genuinely due to the statins: almost all would occur just as frequently on placebo.”

This is confident, seemingly ‘evidence-based’ stuff, indeed. However, these findings do appear to me to be at odds with what I and many other doctors observe in real life: that a significant number of people who take statins have side-effects that resolve (sometimes slowly) on discontinuation of their medication. Of course, as the authors of this most recent study allude to, these side-effects may be nothing more than a negative placebo response – sometimes referred to a ‘nocebo’ response.
However, is there anything about the way statin trials may be designed and conducted that could jeopardise our ability to get accurate data on the adverse effects of these drugs?

Several explanations are possible. First, commercial sponsors of clinical trials may not be motivated to search exhaustively for potential side effects. One pointer towards this is that, although evidence of liver damage is documented in the majority of trials, diabetes diagnoses were only documented in three of the 29 trials assessed in the recent study.

Second, many trials do not state clearly how and how often adverse effects were assessed. Because of this, it far from certain that all adverse events were ‘caught’ and logged appropriately.

Third, some trials’ exclude patients with severe diabetes, kidney failure or high blood pressure. In reality, though, these individuals may come to be prescribed and take statins.

Fourth, trial volunteers tend to be enthusiastic, and may therefore be less likely to report side effects than patients in routine clinical practice.

Fifth, many trials have a ‘run-in’ period where individuals are given a placebo to help ensure adequate compliance with medication. This can cause studies to be ‘enriched’ with highly motivated individuals who, again, may be less likely to complain of side-effects.

Finally, many trials excluded patients on medication sharing the same liver metabolic pathway as statins (e.g. fibrates and macrolide antibiotics). Patients on such drugs, in the real world, might well suffer higher rates of pharmacologically mediated effects.

I make no secret of the fact that I think the benefits of statins are over-hyped and that the adverse effects are generally downplayed. As a result, a cynical observer might read my reservations here and think ‘well, he would say that’.

But, here the kicker: those six issues I detail above were plucked from the very same study that trumpets the safety of statin [1]. Much of what is written in this section of the post was actually lifted verbatim from the study.

So, by the authors’ own admission, there are many reasons why the adverse effect rates seen in statin studies may not accurately reflect the rates seen in the real world. But then how can the authors conclude that: “Only a small minority of symptoms reported on statins are genuinely due to the statins: almost all would occur just as frequently on placebo.”

The reality is the deficiencies of the studies do not allow the authors (or anyone) to conclude that at all. The authors’ pronouncement on safety is utterly undermined by their own admissions about the incompleteness and untrustworthiness of the study data.

The opening line of the study is this: “Patients and doctors need clear reliable information
about benefits and risks to make informed decisions.” The only clear thing about the risks of statins, to my mind, is that there isn’t much clarity. Making bold pronouncements on the safety of statins without us having the facts is potentially misleading, and may cause many to come to considerable harm, needlessly.

References:
1. Finegold JA, et al. What proportion of symptomatic side effects in patients taking statins are genuinely caused by the drug? Systematic review of randomized placebo-controlled trials to aid individual patient choice. European Journal of Preventive Cardiology March 12, 2014

Monday, August 5, 2013

As cholesterol levels are lowered the death rate increases

Analysis of six trials show that as cholesterol levels are lowered the death rate increases
This study was published in the British Medical Journal 1990 Aug 11;301(6747):309-14

Study title and authors:
Lowering cholesterol concentrations and mortality: a quantitative review of primary prevention trials.
Muldoon MF, Manuck SB, Matthews KA.
Department of Medicine, University of Pittsburgh, PA 15260.

This study can be accessed at: http://www.ncbi.nlm.nih.gov/pubmed/2144195

This study analysed the findings of six cholesterol reduction trials. The participants in the six cholesterol reduction trials received either diet based, drug based, a mixture of diet and drug cholesterol lowering treatment or placebo. The trials lasted for an average of 4.8 years and included 24,847 male participants who were followed for a total of 119,000 person years. The average age of the men was 47.5 years.

The analysis found:
(a) The men receiving cholesterol reduction treatment reduced their cholesterol levels by about 10%.
(b) The men receiving cholesterol reduction treatment had a 7% increase in death rates compared to the men taking a placebo.

The results of this analysis of six trials show that as cholesterol levels are lowered the death rate increases.
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Read the complete article here.

Sunday, May 5, 2013

Fears of cancer link to statin - AB Rossebo,

Scientists raise fears of cancer link to statin used by thousands


 
This post includes a synopsis of a study published in the New England Journal of Medicine September 25, 2008; 359(13): 1343-56 and a recipe for roccoli, bacon and nut salad.

Study title and authors:

Intensive lipid lowering with simvastatin and ezetimibe in aortic stenosis.
AB Rossebo, TR Pedersen, K Boman, P Brudi, JB Chambers, K Egstrup, E Gerdts, C Gohlke-Barwolf, I Holme, YA Kesaniemi, W Malbecq, CA Nienaber, S Ray, T Skjaerpe, K Wachtell, R Willenheimer, and SEAS Investigators Division of Cardiology, Aker University Hospital, Trondheimsveien 235, N-0514 Oslo, Norway.

This study can be accessed at: http://www.ncbi.nlm.nih.gov/pubmed/18765433

This trial observed the effects of the drug Inegy (a combination of simvastatin and ezetimibe).The trial was a randomizsd, double-blind trial involving 1,873 patients with mild-to-moderate, asymptomatic aortic stenosis (obstruction of blood flow across the aortic valve). The patients received either 40 mg of simvastatin plus 10 mg of ezetimibe or placebo daily and were followed for 52 months.

The study found:

(a) Those taking the simvastatin/ezetimibe combination had a 4% increased risk of death compared to those taking placebo.

(b) Those taking the simvastatin/ezetimibe combination had a 21% increased risk of death from heart failure compared to those taking placebo.

(c) Those taking the simvastatin/ezetimibe combination had a 67% increased risk of death from cancer compared to those taking placebo.

(d) Those taking the simvastatin/ezetimibe combination had a 195% increased risk of death from violence or accidents compared to those taking placebo.


Professor Heinz Drexel, of the University of Innsbruck in Austria and spokesman for the European Society of Cardiology, said: "I am not sure that the efficacy is proven and I am not sure that the safety is proven. I wouldn't take the drug myself".

In Britain, about 300,000 NHS prescriptions have been dispensed for Inegy in the last two years.
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Read the complete article here.

Friday, December 21, 2012

Real Life vs. Pharma Company Studies - Kendrick

Real Life vs. Pharma Company Studies

December 21, 2012

At what point, exactly, does credibility snap? When does the difference between what we are told, and what we observe, reach such a state of dissonance that it is no longer possible to believe both. Sometimes it seems the answer is ….never.

Here is one example. The clinical trials on statins found that they have virtually no adverse effects. Or, to be a little more accurate, that adverse events were virtually identical to placebo. Here, for example, is part of the press release from the Heart Protection Study (HPS). This was the last major placebo controlled statin study done in people with already diagnosed cardiovascular disease.

As the benefits of statins are now thought so wonderful it would be considered unethical to do a placebo controlled study anymore. You would be withholding statins from people who need them. Which means that you are not going to get any more evidence in this area – ever again. The HPS results were published around ten years ago, and the press release contained the following

‘Although muscle pain was reported by the participants, this happened about as commonly among those allocated the active simvastatin as among those allocated the placebo tablets. Despite 20,536 randomised patients having been followed for an average of five years, blood tests among people reporting muscle symptoms found only 11 simvastatin-allocated patients and 6 placebo-allocated patients with a rise in the muscle enzyme creatine kinase (CK) to more than 10 times the upper limit of normal Of these, 14 met the definition for “myopathy” (i.e. muscle symptoms associated with such CK elevations) of whom 10 were in the simvastatin group and 4 in the placebo group.’

http://www.ctsu.ox.ac.uk/~hps/June02QandA.shtml

Teasing these figures out a little more it seems that an extra six people taking simvastatin suffered muscle ‘problems’ than those taking the placebo. This is six people, out of more than ten thousand taking simvastatin. This represents in one thousand seven hundred and eight 1/1708 (over five years).
If this were true, then muscle problems should be exceedingly rare. The average GP with about two hundred of their fifteen hundred patients taking a statin should see a patient with muscle pains/problems about once every twenty five years. At this rate, you would not even know you had a problem.

Yet, wrapped around my copy of the BMJ last week was an advert for rosuvastatin [Crestor]. The strap line shouted out ‘Myalgia on his initial statin?’ [Myalgia is the medical word for muscle pain]. The main message the advert was… ‘If your patient was suffering muscle pains on their initial statin, they should switch to Crestor 5mg.’

Their ‘initial statin’ will almost certainly be Simvastatin 40mg. The drug, and the dose, used in the HPS study. The same drug, and the same dose recommended by the National Institute of Clinical Excellence (NICE).

Now, you do not run an expensive advertising campaign without doing a lot of market research first. What the market research must have told AstraZeneca – who make Crestor – is that a lot of people are suffering muscle pains on 40mg simvastatin.

Which means that simvastatin, which caused no discernible increase in muscle pains in the clinical study…… actually creates such a massive burden of muscle problems that a pharmaceutical campaign is running a major advertising campaign highlighting this, exact, adverse event.

What does this tell us, gentle reader? It tells us many things. Some of which would be considerable slanderous if I said them out loud. The most outstanding thing it tells me is that, although we have all been repeatedly informed that statins have no more side-effects than placebo, I now find that AstraZeneca encouraging doctors to switch statins due to the burden of side-effects.

F Scott Fitzgerald opined that …“The test of a first-rate intelligence is the ability to hold two opposed ideas in the mind at the same time, and still retain the ability to function.’

I would suggest that there comes a point where you have to decide between which idea is right, and which is wrong. With regard to statins, I did this many years ago when I recognised that they cause a gigantic burden of adverse effects, with muscle pain the single most outstanding. I knew that the clinical trials had somehow or another managed to bury this fact.

Yet, when I speak to most doctors they continue to tell me that statins have very few side-effects, as do most opinion leaders. This belief, whilst AstraZeneca starts up an advertising campaign based on side-effects reported by doctors. F Scott Fitzgerland would be impressed by all these first class intellects. I just despair of them.
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Read the complete article here.

Friday, July 20, 2012

The Polypill has never been proven to benefit anyone - Briffa

It’s easy to fall for the polypill hype, but the reality is this medication has never been proven to benefit anyone

There’s been a ton of press over the last couple of days regarding a study of what is termed the ‘polypill’ – a combination medication conceived more than a decade ago with, supposedly, the prevention of heart disease and stroke in mind. The original ‘formulation’ combined blood pressure- and cholesterol-lowering medications, along with aspirin and vitamin B12. From time to time in the scientific literature we have seen studies which purport to support the idea of polypill taking for disease prevention. And the latest of these was published this week. Here, in short, is the study design and what it showed. After that, I’ll offer my own interpretation of the data.

This latest study tested the impact of a polypill comprising the following drugs:
  • amlodipine (blood pressure lowering medication) – 2.5 mg
  • losartan (blood pressure lowering medication) – 25 mg
  • hydrochlorothiazide (blood pressure lowering medication) – 12.5 mg
  • simvastatin (a statin) – 40 mg
The medication was given for 12 weeks to men and women aged 50 and over. At another time, they took a placebo for 12 weeks. In this sense, individuals acted as their own ‘controls’ in this study.

Individuals were selected for the study on the basis of two criteria:
  1. They needed to be currently taking at least one of the medications in the polypill
  2. They needed to be aged 50 or over
The impact on blood pressure and cholesterol levels was assessed. The polypill did bring significant reductions here. The authors estimate from the degree of reductions here that heart disease and stroke would be reduced by 72 and 64 per cent respectively. Impressive numbers. There’s talk of this extending life by a decade or more.

But here’s the thing: this study simply can’t be used to judge whether the polypill prevent cardiovascular disease and delays death. These ideas are based on speculation based on the idea that lowering blood pressure and cholesterol translates into significant benefits for health. Yet, as I explored most recently here and here, blood pressure and statin medications are generally very ineffective for the purposes of disease prevention and preventing death. Most people who take these drugs just won’t benefit.

This is particularly the case when individuals are deemed to be at low risk of cardiovascular disease. Normally, medication is prescribed on the basis of, say, blood pressure or cholesterol levels. But not in this study: here people were selected on the basis of age, irrespective of perceived risk. Of course it’s possible that some might benefit from the polypill, but it’s also likely that many more will not.

And of course the drugs in the polypill are not without risk. Any one of these medications on its own might cause problems, but the risk is magnified when medication are taken in combination. The design of the study (individuals had to be on at least one of the drugs in the polypill prior to the study) essentially preselects for individuals who, compared to members of the general population, are more likely to tolerate the medication being tested. So, risk of side-effects in the study population would be generally lower than we would expect to see in real life.

But, all of this is a diversion from the main point that we simply cannot predict the value of a drug on its impact on so-called ‘surrogate markers’ such as blood pressure and cholesterol. I mean, who would have predicted that ezetimibe, a potent cholesterol-lowerer, would never be shown to have benefits for health, or that the drug torcetrapib (which lowers ‘bad’ cholesterol and raises ‘good’ cholesterol) happens to increase the risk of people dying?

If we want to know how effective the polypill is, we need to test its impact on health. What impact does the polypill have on risk of heart disease, stroke and overall risk of death? We just don’t know because this latest study does not tell us. There are four previous polypill studies in the literature, and none of them look at these critically important ‘end points’ or ‘outcomes’ either.

The lead author of the latest study is David Wald, son of Professor Sir Nicholas Wald, co-inventor of the polypill. Professor Wald and a colleague (Professor Malcom Law) hold a polypill patent. I suspect they have at least some desire to cash in on their invention. But if they want to do that, why not test the polypill in a way which does not lead to wild speculation but cool hard facts? Perhaps if the polypill was properly studied we’d get to see that, like so many drugs, the ‘expected’ benefits fail to materialise. Maybe it’s better to keep the dream alive with a string of studies and articles that allow rampant speculation and uber-enthusiasm but simply fail to tell us what we really need to know.

References:
1. Wald DS, et al (2012) Randomized Polypill Crossover Trial in People Aged 50 and Over. PLoS ONE 7(7): e41297. doi:10.1371/journal.pone.0041297
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Please read the complete article here.
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Sept 8, 2014 -  An FDA advisory committee looks at a new cardiovascular polypill about which FDA staff expressed serious reservations
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Monday, January 9, 2012

Statin-induced diabetes: perhaps, it’s the tip of the iceberg

From: Oxford University Press Quarterly Journal of Medicine.
http://qjmed.oxfordjournals.org/content/early/2010/11/29/qjmed.hcq230.full

Statin-induced diabetes: perhaps, it’s the tip of the iceberg

The meta-analysis by Mills et al.1 involving 170 255 patients randomized in 76 trials reported on the efficacy and safety of statin therapy for the prevention of cardiovascular disease (CVD) and found a relative 9% increased risk in the development of incident diabetes (P = 0.001) among subjects randomized to statins compared with placebo in the 17 trials reporting on diabetes development. It is noteworthy that the average age of the subjects in the meta-analysis was 59.6 years, average follow-up was 2.7 years and more than half of the subjects were randomized for the primary prevention of CVD. We feel that the implications of statin-induced diabetes are not trivial, but of major concern, particularly in the primary prevention of CVD when statin therapy might be used for decades in individuals at relatively low risk2; many questions need answering before statin therapy can be safely recommended across broad populations.

Interestingly, a recently published meta-analysis involving 91 140 patients randomized in 13 trials3 specifically looking at the risk of incident diabetes from statin therapy also revealed a significant 9% increased relative risk of the development of diabetes over a mean overall trial period of 4 years. Disturbingly, 2 of the 13 trials demonstrated very high incidence of the development of diabetes among the statin-treated subjects. The Justification for the Use of Statins in Prevention: an Intervention Trial Evaluating Rosuvastatin (JUPITER),4 a primary prevention trial of 1.9-year duration in subjects with a mean age of 66 years, demonstrated a significant relative increase in diabetes incidence of 26% among subjects randomized to rosuvastatin; the absolute rate of incident diabetes expressed in events per 1000 patient-years was 13 and 16 among the placebo and rosuvastatin subjects, respectively. Low-density lipoprotein (LDL) cholesterol was decreased robustly by 50% in the rosuvastatin subjects and the median LDL cholesterol at the end of follow-up was 55 mg/dl. The PROspective Study of Pravastatin in the Elderly at Risk (PROSPER),5 a combined primary and secondary prevention trial of 3.2-year duration in subjects with a mean age of 76 years, demonstrated a significant relative increase in diabetes incidence of 32% among subjects randomized to pravastatin; the absolute rate of incident diabetes expressed in events per 1000 patient-years was 16 and 21 among the placebo and pravastatin subjects, respectively. LDL cholesterol was decreased by 31% in the pravastatin subjects. Therefore, it appears that the risk of statin-induced diabetes is more prominent with aggressive LDL cholesterol lowering and among the elderly subjects. It is of concern that thought leaders in the cardiovascular arena strongly suggest that statin use should be increased from 16 to 100 million people in the USA and LDL cholesterol should be aggressively lowered.6 This issue takes even more relevance given that the prevalence of diabetes is rapidly increasing in the USA7 and worldwide8; alarmingly, three-quarters of the elderly in the USA have diabetes or pre-diabetes.7

In vivo studies have demonstrated that despite lowering LDL cholesterol levels, some9–11 but not all statins11 significantly increase fasting plasma insulin levels and significantly decrease insulin sensitivity in hypercholesterolemic patients in a dose-dependent manner. Statins can significantly increase fasting plasma insulin levels and glycated hemoglobin levels in the absence of significant changes in fasting glucose.9–11 Additionally, some statins have been shown to significantly decrease plasma adiponectin levels.10,11

In vitro and animal studies12,13 have shown that statins can significantly decrease the expression of the insulin-responsive glucose transporter 4 (GLUT4) in adipocytes. GLUT4 is distributed in the intracellular compartment in the basal state and relocates to the cell membrane in response to insulin signaling. Moreover, statins increase the expression of GLUT112 in adipocytes; GLUT1 is localized in the cell membrane. It is unclear how statins change the expression of GLUT1 and GLUT4; perhaps, it is related to an inhibition of isoprenoid biosynthesis by statins12 or cholesterol lowering, leading to a change in membrane lipid raft structure resulting in decreased insulin signaling.14 Since GLUT4 concentrations are not reduced in skeletal muscle in obese subjects and subjects with diabetes, and skeletal muscle is the primary source of insulin-stimulated glucose disposal, it has been argued that whole-body insulin sensitivity cannot be explained by a decrease in the production of GLUT415; however, it has been shown that the downregulation of GLUT4 and resulting glucose transport in adipose tissue can cause insulin resistance.16 It is notable that GLUT4 concentrations are decreased in skeletal muscle in elderly compared with younger subjects,15 which might explain why the elderly are more sensitive to the diabetes promoting effects of statin therapy. Furthermore, dysregulation of cellular cholesterol may attenuate pancreatic β-cell function, since cholesterol maintains normal function of voltage gated calcium channels and is vital in the mobilization and fusion of insulin granules with the cell membrane.17 In summation, there are many ways by which statin therapy might lead to hyperinsulinemia, insulin resistance, prediabetes and diabetes.

In addition to the classic complications of diabetes such as CVD, renal failure, blindness and neuropathy, epidemiological studies demonstrate that diabetes is related to the increased risk of many cancers.18 These include liver, pancreas, kidney, endometrial, colorectal, bladder and breast cancer and non-Hodgkin’s lymphoma. A large European population study with a median follow-up of 15.8 years has shown that compared with individuals with normal glucose tolerance, men and women with prediabetes or diabetes had a significant increase in cancer mortality, irrespective of the body mass index.19 There is epidemiological evidence that insulin resistance is associated with cancer in Eastern populations.20 Interestingly visceral fat mass, assessed by computed tomography, but not subcutaneous fat mass, correlates positively with cancer21; indeed, visceral fat is a strong determinant of insulin resistance and hyperinsulinemia.

There are many ways by which hyperinsulinemia can promote cancer.18,22 Hyperinsulinemia results in an increase in the biologically active free circulating insulin-like growth factor-1 (IGF-1) by increasing hepatic IGF-1 production22 and decreasing IGF-1 binding proteins.18 Tumor cells are replete with IGF-1 receptors and two isoforms of insulin receptors (IR-A and IR-B).23 IGF-1 primarily signals through the IGF-1 receptor resulting in mitogenic effects and, not surprisingly, higher IGF-1 blood levels have been associated with an increased risk of several cancers.24,25 Insulin signaling through the IR-A and IR-B results in mitogenic and metabolic effects, respectively.22 Hyperinsulinemia can persist for decades in prediabetic states and it is certainly conceivable that this prolonged mitogenic stimulus increases cancer promotion as has been seen in epidemiological studies.

Statin therapy might affect tumor metabolism by insulin independent means. As previously mentioned, some statins decrease adiponectin levels.10,11 This is potentially problematic over the long-term since adiponectin is anti-proliferative and anti-angiogenic and has other oncostatic properties.26 Furthermore, obesity is associated with lower circulating adiponectin levels and this might partially explain the association of obesity and various cancers. Additionally, the fact that statin therapy might increase GLUT1 expression12 is of concern since GLUT1 is already overexpressed and is the main glucose transporter in cancer cells.27 Glucose uptake by cancer cells is extremely avid and up to 30 times that of normal cells and utilized by glycolysis for energy and supplying important metabolites for rapid cellular proliferation.28 Indeed, in human studies, increased expression of GLUT1 in cancer cells has been associated with poor prognosis of many cancers.27,29

The Western diet is permissive to the diabetogenic effects of statin therapy. The prevalence of obesity has been steadily increasing in the USA and more than two-thirds of adults are overweight or obese.30 As mentioned, the prevalence of diabetes has been increasing in the USA and a majority of the elderly subjects in the USA now have pre-diabetes or diabetes.7 Interestingly, total cholesterol and LDL cholesterol have been decreasing in the USA likely due to cholesterol awareness and the increased use of lipid-lowering medication, and more than half of the elderly subjects in the USA have reported using lipid-lowering medications.31 However, blood triglyceride levels have been steadily increasing despite the increasing use of lipid-lowering therapy.31 Intriguingly, it is now believed that abnormalities in fatty acid metabolism are at the root of diabetes, and ectopic lipid accumulation in muscle, liver and pancreatic β-cells leads to the development of insulin resistance by interfering with insulin signaling.32,33 The increase in blood triglyceride levels is driven by a high carbohydrate diet and partially fueled by the increase in dietary sweetener consumption.34 Unfortunately, fructose consumption, largely from sweetened beverages, has escalated drastically in North America over the past three decades35 and excessive fructose intake leads to increased hepatic de novo lipogenesis resulting in hepatic steatosis, visceral fat accumulation and ectopic lipid deposition in skeletal muscle, thereby all leading to insulin resistance.

We are living in times when there seems to be a much stronger emphasis on the use of drugs over lifestyle change to prevent disease. The food industry has been uncooperative and blames personal responsibility as a cause of the obesity problem.36 There is a belief among many patients that they can eat whatever they want as long as they are on statin therapy.37 This has been amplified by a proposal to offer powdered statin in packets to be sprinkled on hamburgers at fast-food restaurants in order to neutralize the detrimental effect of the food choice.38 Plant-based diets have been shown to decrease both CVD and cancer risk and even result in a rapid change in gene expression in neoplastic tissue, and they are not diabetogenic.39–41 Moreover, a Mediterranean diet has been shown to counter the insulin raising effects of simvastatin therapy.42 It is extremely troubling that a goal has been proposed for decreasing the LDL cholesterol levels of all subjects worldwide to below 100 mg/dl and ideally below 60 mg/dl by statin therapy.43

In conclusion, many important questions need answering before expanding the use of statin therapy, particularly for the primary prevention of CVD. In what proportion of subjects do statins increase plasma insulin levels, even if there is no progression to diabetes? Are some statins more likely than others to cause hyperinsulinemia because of physiochemical differences? Will prolonged statin therapy result in chronic hyperinsulinemia and potentially increase prediabetes, diabetes and/or cancer? Will this risk outweigh any perceived benefits, particularly in the elderly or in aggressively treated patients? Will the Western diet and lifestyle encourage the use of more statin therapy and provide a metabolic substrate to further perpetuate hyperinsulinemia and its subsequent complications? Is the increase in diabetes prevalence in the elderly subjects fueled partially by the increasing use of statins in this age group? What statins decrease blood adiponectin levels, and is it continuous, and, if so, what are the long-term clinical implications? How should physicians monitor patients for the adverse metabolic effects of statin therapy? Should subjects have a plasma insulin level measured prior to initiating and during statin therapy? What diet or diets will mitigate the hyperinsulinemic effects of statin therapy? Will statin therapy used by subjects with a history of cancer increase the chance of hyperinsulinemia increasing the promotion of occult micrometastatic disease? Finally, physicians should realize that statin-induced diabetes, as seen in the relatively short-term clinical trials, might be just the tip of the iceberg, and properly designed clinical trials must be done to determine what else lurks beneath the water in order to ensure the safety of patients on long-term treatment with these drugs.

Friday, August 12, 2011

Scientists sometimes shift the scientific goalposts

Dr. John Briffa

Scientists sometimes shift the scientific goalposts

It’s easy to believe that statins have dramatic life-saving properties. The reality is, however, that for the majority of people who take them, they don’t. In the biggest and best review published to date, statins were not found to reduce overall risk of death in individuals with no previous history of cardiovascular disease [1]. What this study shows is that for great majority of people who take statins, the chances of them saving their life are, essentially, nil (just so you know).

Of course, you wouldn’t expect everyone to take this finding lying down. A number of people responded to this study with letters to the journal in which it appeared, attempting to cast doubt on its findings. None of it amounted to much, but I thought I would focus on one response, which in my view demonstrates how some scientists and doctors attempt to shift the scientific goalposts to make their point and suit their ends.

The response came from Drs Gabriel Chodick and Varda Shalev [2]. The main thrust of their objections come in the form of three studies that were included in the review referred to above that they claim have ‘major limitations’. Here’s what they say about each of these studies:

“…their meta-analysis included 3 studies with major limitations: a significant decrement in low-density lipoprotein cholesterol levels over the study period in the placebo arm (Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial [ALLHAT]), old age at therapy initiation (Pravastatin in Elderly Individuals at Risk of Vascular Disease [PROSPER] Study), and incomplete information on low-density lipoprotein cholesterol levels over the follow-up period (Air Force/Texas Coronary Atherosclerosis Prevention Study [AFCAPS/TexCAPS]). All these studies showed negative results; their inclusion would have biased against finding a benefit to statin treatment.”

With regard to the first study, what Drs Chodick and Shalev seem to be saying is that the control group (the group treated with placebo rather than statin) saw natural reductions in cholesterol, so the benefits of taking a statin did not to show up. However, the impact that statins had on cholesterol levels relative to a control group is not important – the only important thing is the impact statins had on health (and, in particular, overall risk of death). This is also true for the last study highlighted by Drs Chodick and Shalev.

As regard the second study, it’s not clear why the advanced years of participants would be a barrier to determining the effectiveness of statins. Actually, the elderly are known to be at particularly high risk of cardiovascular disease, meaning that if anything, this population would, theoretically, be generally most likely to benefit from statin therapy.

In summary: none of Drs Chodick and Shalev’s objections hold any water at all. But they don’t stop there. Here’s the final paragraph from their letter.

“Also, randomized controlled trials are often characterized by limited follow-up periods. Therefore, all-cause mortality benefits may not be apparent in randomized controlled trials among a primary prevention population. It would be informative in this regard to take into account the results of large observational studies with longer follow-up periods to better capture the benefits of statins in primary prevention patients.”

What they’re saying here is that clinical trials don’t go on long enough to detect benefits. It’s better, in their mind, to revert to longer studies that are observational (also known as ‘epidemiological’) in nature. However, such studies look at associations between things, but can never be used to prove the benefits of statins. Only intervention studies can do this.

So, what the authors of this letter are effectively saying is that we should ignore the best evidence we have in favour of quite-useless epidemiological evidence.

One of the authors of this letter is, in fact, an epidemiologist, and really should know better. But then again, both of the authors work for a company that assists drug companies in, among other things, ‘reducing the time to market’ and the writing and submission of scientific articles for publication.

See here for more details. It’s a clear conflict of interest, of course, and perhaps goes some way to explain why they make apparently spurious objections to existing evidence and appear to be calling for an approach that can never really get to the truth.

References:
1. Ray KK, et al. Statins and all-cause mortality in high-risk primary prevention: a meta-analysis of 11 randomized controlled trials involving 65 229 participants. Arch Intern Med. 2010;170(12):1024-1031
2. Chodick G, et al. Statins and all-cause mortality in high-risk primary prevention: a second look at the results. Arch Intern Med. 2010;170(22):2041-2
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Read the full article here.