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Diet, Heart Disease, New Study, Prevention
This week I discovered how painful it can be to change a habit. Not because it means admitting I was doing the wrong thing, but because it means analyzing how feeble my reasons were for the habit in the first place.
Ever since I started practice I’ve been recommending calcium supplements to post-menopausal women. Why? Mostly out of habit. There’s not a shred of evidence that calcium supplements prevent fractures, but some suggestion that they may help bone density. But what’s the harm? Calcium supplements are safe and wholesome and natural, right?
Last week the journal BMJ published a meta-analysis of randomized trials which compared calcium supplement against placebo. (Expand your geeky medical literature vocabulary! A meta-analysis is a study that systematically reviews already published studies on a particular topic and statistically pools together the results of all these studies. The goal of a meta-analysis is to reach a more definitive conclusion than the individual studies did.) It’s important to note that these trials were not studying the effects of calcium supplement on heart attacks. They were each looking at the effect of calcium on different outcomes – bone density, fractures, colon cancer, whatever. The investigators looked through the original study data and (where the data was available) counted the numbers of heart attacks in patients taking calcium supplements and in those taking placebo.
For the studies in which data was available on individual patients, about 3.5% had heart attacks on calcium while about 2.7% had a heart attack on placebo over an average follow up of 3.6 years. That may not seem like a big difference but it means that for every 69 patients on calcium rather than placebo for 5 years there was one extra heart attack. Some media reports characterized this as a small increased risk of heart attacks, but it’s not. It’s in the same numerical ballpark as the decrease in heart attacks from treating high blood pressure.
Even if this harm was numerically small, remember, we have to weigh it against a completely unproven benefit. Doctors have been recommending calcium supplements on the assumption that they prevent fractures, an assumption that has not been demonstrated in trials. The study calculates that, even taking optimistic estimates for fracture reduction from calcium supplements, treating 1,000 people with calcium supplements for five years would cause an additional 14 heart attacks and prevent 26 fractures. That’s a terrible tradeoff.
So calcium supplements seem to be a bad idea. But there are some important additional points. First, the authors were careful to state that dietary calcium (calcium in your food, not in supplements) has never been implicated in heart attack risk and is presumably safe. So we should be getting our calcium in our diets, not in supplements. Second, this study did not address vitamin D, which has many proven benefits that calcium does not. So keep taking your vitamin D supplements. Finally, patients with osteoporosis who are taking medications that rebuild bone need excellent calcium intake for the medication to be effective. In these patients, who are at high risk for fracture, the benefit of calcium supplements may be greater than the risk.
An editorial in the same issue of BMJ concluded that “given the uncertain benefits of calcium supplements, any level of risk is unwarranted,” and that calcium supplements “should not be given without concomitant treatment for osteoporosis.”
So as painful as it is to change my mind about something I thought was completely benign two weeks ago, for my patients who do not have osteoporosis, I recommend stopping calcium supplements. Obviously, if you have questions about your unique situation, ask your doctor.
Maybe next week I’ll find out that smelling roses causes seizures.
Learn more:
BMJ article: Effect of calcium supplements on risk of myocardial infarction and cardiovascular events: meta-analysis
BMJ editorial: Calcium supplements in people with osteoporosis
LA Times Booster Shots: Calcium supplements increase the risk of heart disease in the elderly, study says
My regular readers are a sharp bunch, so you probably already know that cardiac arrest – the cessation of a pulse and of blood circulation – is very very bad for you. Most doctors don’t recommend it. Nevertheless, hundreds of thousands in the U.S. every year suffer cardiac arrest outside of a hospital, frequently due to a heart attack. Cardiopulmonary resuscitation (CPR) was developed 50 years ago for just such situations. Decades of data strongly support that the following two factors are key in determining survival after out-of-hospital cardiac arrest.
Despite this information, only a third of cardiac arrest patients receive CPR from bystanders.
Two years ago the American Heart Association revised their recommendations for CPR done by bystanders. (I wrote about it back then. See the link below.) The new recommendations removed mouth-to-mouth rescue breathing and focused on chest compressions. The recommendations have only two steps.
If you see someone collapse:
These recommendations received substantial support from two studies in this week’s New England Journal of Medicine. The studies, one Swedish and one American, involved emergency dispatchers who were called regarding a witnessed cardiac arrest. The dispatchers instructed the callers on how to perform CPR. The calls were randomized so that half of the bystanders were instructed to perform traditional CPR with 15 chest compressions alternating with two rescue breaths. The other half of the callers were instructed to do chest compressions only, without rescue breaths.
Both studies showed equal survival rates between the two groups, suggesting that rescue breaths are not helpful. The previous emphasis on rescue breathing may also have discouraged bystanders from doing anything at all, as many people find mouth-to-mouth resuscitation objectionable because of infection risks or general ickiness.
The major exception to these guidelines is cases in which the patient collapsed because of a breathing problem, such as choking or drowning. In these cases rescue breathing should be done with chest compressions. Since kids don’t have heart attacks, a collapsed child should be assumed to have had a breathing problem.
The bottom line is that if you see someone collapse, get help, and do something. You can’t make the situation worse, and prompt chest compression can make things much better.
Learn more:
Wall Street Journal article: In Many CPRs, Skip the Mouth-to-Mouth
Los Angeles Times article: Compression CPR Found Effective
My post in 2008: American Heart Association Recommends Hands-Only CPR
New England Journal of Medicine article: CPR with Chest Compression Alone or with Rescue Breathing
New England Journal of Medicine article: Compression-Only CPR or Standard CPR in Out-of-Hospital Cardiac Arrest
New England Journal of Medicine editorial: In CPR, Less May Be Better
Cancer, Heart Disease, New Study
This week the American Cancer Society published its annual review of cancer statistics and trends. This year the big picture was overwhelmingly positive.
The three most frequently diagnosed cancers in men are prostate cancer, lung cancer, and colorectal cancer (in that order). For women the top three are breast, lung and colorectal cancer. (See the link below to Figure 1 in the study for details.) The incidences (the numbers of new diagnoses every year) of all of these cancers have decreased in the last few years, except for lung cancer in women, which is still increasing but at a slower rate than previously.
The continued decline in lung cancer in men is attributed to the decrease in smoking in men in the last few decades. Women, on the other hand, started smoking in significant numbers later than men in the twentieth century, but also continued to smoke after men were quitting. The peak of number of women smokers was 20 years after the peak for men, so the decline in lung cancer in women hasn’t happened yet (but will).
Colon cancer incidence continues to fall in both men and women, likely because of increased colon cancer screening with colonoscopy, leading to the removal of pre-malignant polyps.
In terms of deaths caused by cancer, the top four causes for men are (in order) lung, prostate, colorectal and pancreas. For women the top four are lung, breast, colorectal and pancreas. Note that prostate cancer and breast cancer are the most common causes of cancer in men and women, but since they are very treatable and sometimes even curable, they are only the second most common causes of cancer death. The opposite case is pancreatic cancer. It is the tenth most common cause of cancer, but because it is so frequently fatal, it is the fourth most common cause of cancer death.
Fortunately, the mortality rates from lung, breast, prostate and colorectal cancer are all falling, likely due to improvements in diagnosis and treatment. So over all, fewer Americans are dying of cancer due largely to advances in the treatments for these top four killers. Interestingly, mortality from pancreatic cancer has not changed dramatically, making me wonder whether it will overtake colon cancer as the trends continue.
During the same years in which these positive trends were occurring in cancer, major advances were also being made in heart disease. Because of improved treatments for blood pressure and cholesterol, and because fewer Americans are smoking, the mortality from heart disease has been falling for many years. Heart disease is still the most common cause of death in the US, with cancer a close second. Because of the drop in heart disease mortality, cancer is now the leading cause of death for those 85 and younger. (See the link below to Figure 6 for details.)
That’s all very encouraging news, except that it probably means that our children will all die of pancreatic cancer or Alzheimer’s disease. Perhaps our grandchildren will return to smoking…
Learn more:
American Cancer Society article: Cancer Statistics, 2010
Figure 1: Ten Leading Cancer Types for the Estimated New Cancer Cases and Deaths by Sex, 2010.
Reuters article: U.S. cancer death rates continue drop: report
Heart Disease, New Study, Prevention
Three months ago I wrote about carotid artery narrowing, which is one of a number of causes of stroke. There are currently two alternative treatments for severe carotid artery narrowing: surgery, called endarterectomy, to open the artery, and a newer procedure called carotid artery stenting. (Read my previous post, link below, for some background about these procedures and their role in stroke prevention.)
Thus far, carotid artery stenting has not been shown to be as safe as endarterectomy. So endarterectomy has remained the proven standard.
This week stenting finally gains some credibility in the largest study to compare the two treatments, published in this week’s New England Journal of Medicine. Over 2,500 patients with carotid artery narrowing were randomized to stenting or endarterectomy. They were followed for serious complications immediately after the procedure or for strokes in the subsequent years.
Surprisingly, the patients receiving stenting did overall as well as the patients undergoing endarterectomy, making this the first study in which endarterectomy was not clearly superior. Stenting carried a slightly higher risk of stroke after the procedure, but endarterectomy had a higher risk of heart attack. Interestingly, patients younger than 70 tended to do better with surgery, while older patients did better with stenting.
So stenting is finally finding some role in treating carotid artery narrowing. Training and experience in the physician performing either procedure is vital.
An editorial in the same issue of the New England Journal of Medicine concludes
… until more data are available, carotid endarterectomy remains the preferred treatment for most patients with symptomatic carotid stenosis; treatment for asymptomatic stenosis remains controversial. However, given the lack of significant difference in the rate of long-term outcomes, the individualization of treatment choices is appropriate.
Learn more:
New England Journal of Medicine article: Stenting versus Endarterectomy for Treatment of Carotid-Artery Stenosis
New England Journal of Medicine editorial: Carotid-Artery Stenting in Stroke Prevention
LA Times Booster Shots: Angioplasty plus stents is as good as surgery for clearing neck arteries, study finds
My previous post about carotid artery stenting: Carotid Stenting Still Controversial
Diet, Exercise, Heart Disease, New Study, Weight Loss
Weight loss is one of the most common recommendations that doctors make. How do we know if a patient should lose weight? We usually use the Body Mass Index (BMI) which is a way to compare a patient’s weight to her height. (For all you math geeks, it’s the weight in kilograms divided by the height in meters squared. For all you physicists, I know the units make no sense.) A BMI of 18.5 to 25 is considered normal. A BMI of 25 to 30 is considered overweight, and over 30 is considered obese. (See the link below to calculate your BMI.)
An article in the health section of Tuesday’s Wall Street Journal reminds us that BMI may not be telling us the whole story. The article cites a study published in the European Heart Journal last year which followed over 6,000 adults with a normal BMI. They all had their body fat percentage measured and were followed for about 9 years.
Surprisingly, even in these adults with a “normal” weight, those with a high body fat content had a higher likelihood of high blood pressure, high cholesterol and cardiovascular disease.
This study is too small to be definitive, and it’s observational, not randomized. So we don’t know whether lowering body fat reverses any of these risk factors. I’m not suggesting we all run out to measure our body fat content. Still the article suggests a few tantalizing possibilities.
First, dieting may not be enough in improving cardiovascular health. It may decrease overall weight without decreasing percent body fat. Exercise is critical to burn fat and build muscle, thereby decreasing percent body fat.
Second, thin people who are inactive may have a high body fat percentage and may be falsely reassured by their “normal” weight. This is what the authors call “normal weight obesity”.
Finally, for those of you who are exercising and not losing weight, don’t despair. You may be losing inches from your waist, burning fat and building muscle, muscle while your weight stays the same. Going by the weight alone is a recipe for frustration when in reality your health is improving.
Learn more:
The Centers for Disease Control BMI calculator
Wall Street Journal article: The Scales Can Lie: Hidden Fat (only by subscription)
European Heart Journal article: Normal weight obesity: a risk factor for cardiometabolic dysregulation and cardiovascular mortality
Heart Disease, New Study, Prevention
Aspirin has long been known to prevent strokes and heart attacks in patients with a previous stroke or heart attack. But aspirin has potentially serious side-effects. Aspirin can cause stomach ulcers, and it inhibits blood clotting raising the risk of life-threatening bleeding.
If we knew in advance that a patient was going to be in a car accident or have a bleeding stomach ulcer, we would discontinue the aspirin a week before the event and minimize the bleeding risk. (This is exactly what we do in anticipation of routine surgery.) But of course such events don’t herald themselves, so doctors are left reacting to adverse events after they occur. If a patient has life-threatening bleeding we stop the aspirin and consider that the risk may outweigh the benefits. If the patient months or years later has a stroke we reconsider restarting the aspirin. But this strategy is irrational. What is needed is a way to balance risks and benefits of aspirin based on the likelihood of future events, regardless of which event happened most recently.
A study published in this issue of Annals of Internal Medicine examines the wisdom of the current practice of discontinuing aspirin after bleeding from stomach ulcers. The study followed 156 patients who had been taking aspirin for stroke or heart attack prevention and developed bleeding stomach ulcers. All patients had endoscopy to determine the site of bleeding and to stop the bleeding. They were all then started on acid suppressing medication to decrease the risk of future bleeding. Half the patients were randomized to continue 80 mg of aspirin daily and the other half to placebo.
The patients were followed for 8 weeks to test whether the patients on aspirin had more recurrent bleeding than those on placebo. The hope was that the acid blocking medication would make the aspirin safe. It didn’t. Significantly more patients had bleeding on aspirin than on placebo. But surprisingly, more patients died on placebo than on aspirin. The reason was that more patients had strokes and heart attacks on placebo.
This study is too small to reach definitive conclusions, but its results should rattle our current thinking. Rather than stop aspirin because an adverse effect occurs, the right course may be to remember why we recommended aspirin in the first place. After all, strokes and heart attacks are much harder to fix than bleeding ulcers.
Learn more:
Annals of Internal Medicine article: Continuation of Low-Dose Aspirin Therapy in Peptic Ulcer Bleeding
Annals of Internal Medicine editorial: Aspirin Withdrawal in Acute Peptic Ulcer Bleeding: Are We Harming Patients?
Tangential miscellany:
My post last week, Antidepressants for Mild Depression May Not Help Much, generated many interesting comments, some from the handful of psychiatrists and psychologists who are my patients. Many comments pointed out important limitations of the study I wrote about. Two psychiatrists pointed me to the following New York Times articles which make the case that antidepressants are more beneficial than the study I cited suggests. I’m grateful to all who wrote to me.
New York Times article: Before You Quit Antidepressants …
New York Times Op-Ed: The Wrong Story About Depression
Heart Disease, New Study, Prevention
Atrial fibrillation is a very common abnormal heart rhythm affecting 3 million Americans. The most dangerous complication of atrial fibrillation is stoke, which can happen when a blood clot forms in the fibrillating heart chambers and travels to the brain.
Blood thinners have been the mainstay of treatment for atrial fibrillation. They reduce the risk of stroke by preventing blood clots. Warfarin (marketed under the brand name Coumadin) is the most effective available oral blood thinner, but taking it is fraught with difficulty. The appropriate dose varies widely between individuals because of genetic differences, and even in the same individual the correct dose varies from one time to another. The only way to dose warfarin correctly is to check blood tests periodically and adjust the dose based on the results. Too much warfarin and the risk of dangerous bleeding increases; too little and the risk of stroke from atrial fibrillation is undiminished. This need for frequent lab monitoring and the many interactions that warfarin has with foods and with other medications make it one of the least convenient and potentially most dangerous medicines in common use. But for atrial fibrillation warfarin is the best we have.
An important study in this week’s New England Journal of Medicine compares a new blood thinner, dabigatran, with warfarin. Over 18,000 patients with atrial fibrillation were randomized to either warfarin or to two different doses of dabigatran. The lower dose of dabigatran was as effective at preventing strokes as warfarin, but was safer, causing fewer incidents of major bleeding. The higher dose of dabigatran was as safe as warfarin (i.e. equal numbers of major bleeding) but prevented more strokes.
That by itself would be encouraging enough, but the major advantage for many patients will be that dabigatran does not require laboratory monitoring and has much fewer interactions with other medications. It is taken twice a day at a fixed dose, making it dramatically simpler than taking warfarin.
Dabigatran should be available in the US in 2010.
Learn more:
Wall Street Journal article: New Blood Thinner Matches Warfarin
New England Journal of Medicine article: Dabigatran versus Warfarin in Patients with Atrial Fibrillation
New England Journal of Medicine editorial: Can We Rely on RE-LY?
Tangential miscellany:
To my Jewish readers I extend wishes for a sweet and healthy year. To my readers who, like me, are astronomy geeks: happy fall equinox!
Heart Disease, New Study, Prevention
Many of my patients ask me whether they should take red yeast rice to lower their cholesterol. This week’s issue of The Medical Letter has a very handy review of red yeast rice which I summarize below.
Red yeast rice is a food that is produced by fermenting rice with a specific species of yeast. It has been used in Chinese cooking and medicine for centuries. It contains many molecules that are similar to statins, the family of medicines including Liptor, Zocor and Crestor. In fact one of its ingredients is lovastatin, the medication in Mevacor, the first statin approved in the US.
Statins have been repeatedly proven to prevent strokes and heart attacks, but statins also sometimes cause muscle or liver inflammation, a side effect also present in red yeast rice.
Because it is sold as a food supplement, not as a medication, the quantity of active ingredients in red yeast rice formulations is not standardized and varies widely.
The article concludes that red yeast rice has many of the benefits and side effects of statins but unlike statins, its ingredients are not standardized. The bottom line is that “generic lovastatin would be safer and cost less”.
Learn more:
The Medical Letter review of Red Yeast Rice (by subscription only)
The CDC says that September is National Cholesterol Education Month, and who am I to argue? So here is a dollop of education about cholesterol.
So if you haven’t had your cholesterol checked in years, or if you know your cholesterol is high and you’ve been desperately ignoring it, get back to your doctor and get her advice.
Learn more:
The CDC webpage for National Cholesterol Education Month
Tangential miscellany:
My last post, Rational Rationing, generated lots of email responses and led to very stimulating discussions.
This month The Atlantic published a terrific article on the problems of our current healthcare system written by media and technology executive David Goldhill. (Thanks to Timo K. for pointing me to it.) It’s a very well researched and very personal analysis of what’s wrong and how to fix it. I urge you to read it. How American Health Care Killed My Father
Have a happy and safe Labor Day.
Diabetes, Heart Disease, New Study, Prevention
“If you think health care is expensive now, wait until you see what it costs when it’s free.”
– P.J. O’Rourke
I’ve written several times about the proven benefits of a family of cholesterol-lowering medicines called statins. Statins include the medications Crestor, Zocor, Lipitor, Mevacor, Pravachol and others. The group has a solid base of evidence showing that they prevent strokes and heart attacks in patients with high cholesterol and in patients who have had a stroke or heart attack.
This week, a study published in the New England Journal of Medicine brought us more good news about statins, and potentially broadened their usefulness. The study has received a lot of attention in the mainstream press. The study randomized over 17,000 patients who:
C-reactive protein (CRP) is a blood test that is a general marker for inflammation. CRP has long been known to be elevated in people at higher risk for heart attack, but until now, there’s never been anything known to decrease that risk.
The patients were randomized to Crestor 20 mg daily or placebo and were followed for an average of almost two years. The patients on Crestor had fewer heart attacks, fewer strokes and fewer deaths from any cause – a pretty remarkable finding in a group of patients who are not at high risk of cardiovascular illness.
These results strongly support checking a CRP in older men and women and considering statin therapy in those with an elevated CRP regardless of their cholesterol levels. There are some caveats, though. This group of patients had a fairly low risk of adverse events and it took a very large number of patients to show a difference between Crestor and placebo. Extrapolating from the results of the study, it would take treating about 277 patients for two years with Crestor to prevent one heart attack, and 346 patients to prevent one stroke. Using the current price of Crestor, the cost of Crestor needed to prevent one adverse event is over $170,000. The price would be less with a generic statin, but it’s still a big expense and a lot of patients taking a statin who don’t benefit. But we don’t know ahead of time who is the one patient who will have the stroke or heart attack.
So will I recommend checking a CRP to my older patients? Yes. Will I recommend statins to patients with an elevated CRP? Probably, but with the explanation that the benefit may be quite small.
Economists call this the law of diminishing returns. The more resources you spend on a problem (in this case, stroke and heart attack prevention) the less benefit you get from each incremental increase in spending. At some point the possible benefit is so vanishingly small that costs aren’t worth it, but that point is different for every patient. Each one of us has different preferences, different attitudes about risk, and different ways to spend our finite resources. In a free market each patient would balance the risks and benefits herself, but in our current system in which we all indirectly pay for each other’s medicines the decisions will likely be made by insurance companies and by national expert groups.
(I’m grateful to my colleague Dr. Roy Artal and to the several patients who emailed me about this story.)
Learn more:
New England Journal of Medicine article: Rosuvastatin to Prevent Vascular Events in Men and Women with Elevated C-Reactive Protein
New York Times article: Cholesterol-Fighting Drugs Show Wider Benefit
USA Today article: Crestor would save lives at $500,000 each