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What's the latest news in the medical journals this month? Find out what your doctor is reading.

Long-term Use of Beta Blocker Drugs May Be Overrated
How Lack of Sleep May Be Related To Diabetes
More News in Brief: Injections Contaminated by Fungus Have Sickened Hundreds; Smoking Bans Get Health Results Quickly; Women Who Quit Smoking Gain 10 Years; and Hip "Resurfacing" Doesn't Compare Well to Total Hip Replacement Surgery

Long-term Use of Beta Blocker Drugs May Be Overrated

A four-year study has shown that some people who take beta blockers are not getting much benefit from long-term use.

Beta blockers include drugs like metoprolol (Toprol, Lopressor), atenolol (Tenormin), and carvedilol (Coreg). They limit some of the effects of adrenaline, your main stress hormone. (Adrenaline increases your heart's work by triggering "alpha" and "beta" receptors.) When you take a beta-blocker medicine, your heart beats slowly and steadily. And with less stress.

Doctors trust beta blockers. They:

Do a good job treating high blood pressure
Are the first choice of medicine to help angina, because they allow people to have fewer chest pain symptoms and better exercise tolerance
Improve survival for people who have heart failure. If you have a heart attack, beta blockers used at the time of your heart attack can limit the amount of damage that the heart attack causes.
Improve survival from heart attacks in the initial months after the event

These medicines are so important that some hospital review boards judge a hospital's quality by whether most or all of the heart attack patients are sent home with a prescription for a beta blocker.

But are we using beta blockers for too many patients, and for too long? Some doctors routinely recommend a beta blocker even for people who have coronary artery disease but no symptoms — people with no angina and no heart attack. And some doctors even offer the medicines to people who have risk factors for heart disease, such as high cholesterol or diabetes, but do not have proven problems with their heart or arteries.

A new study of more than 20,000 adults taking beta blockers found no clear benefit on mortality (death) rates. The study lasted for almost 4 years. The study was published online by the Journal of the American Medical Association on October 2.

The study also looked at people who had suffered a heart attack years before. We know that beta blockers improve survival in the early months after a heart attack. Previous studies have made it look like there is a long-term benefit, too. But this large 4-year study — one of the largest and longest studies that has looked at this question — could not confirm a long-term benefit. It is possible that most of the benefit from beta blockers happens in the first year or two after a heart attack. Perhaps heart attack patients do not need to stay on a beta blocker for a lifetime.

Beta blockers do cause side effects. They can make the heart beat too slowly. They can cause fatigue, dizziness, nightmares or insomnia, impotence in men, depression symptoms in some people. They might worsen wheezing in people with lung disease. Elderly patients are particularly likely to have side effects.

For people with risk factors only (no true heart disease), taking a beta blocker does not seem to be worthwhile. And while doctors will definitely still recommend beta blockers to heart patients, this study might change how long we keep them on the medicine list. For people with heart failure, beta blockers are known to be helpful. For heart attack patients who do not have heart failure, more studies will need to be organized to tell us the ideal amount of time to keep taking a beta blocker.

How Lack of Sleep May Be Related To Diabetes

Previous research has linked a lack of sleep to a higher risk for obesity and diabetes. A new, but small, study looked at the cells of people who don't get enough sleep. This study might explain why lack of sleep is linked to diabetes. The journal Annals of Internal Medicine published the study October 16.

Type 2 diabetes is caused by "insulin resistance," which is a change in the way cells react to insulin. Insulin is a hormone that controls the entry of blood sugar into cells. This process does not work efficiently when there is insulin resistance. If you have insulin resistance, the pancreas needs to make and release higher levels of insulin into the blood to overcome the resistance.

Seven healthy adults were assigned to sleep either 8.5 hours or 4.5 hours in a sleep lab for 4 nights in a row. After a 2-week break, the groups switched sleep times. After each 4-day cycle, researchers took samples of fat cells from the abdomen wall of the subjects. They also did blood tests to measure insulin. Insulin levels were nearly 3 times higher after people were sleep deprived. Also, cells that were sampled after the sleep-deprived period were 30% less able to respond to insulin when they were studied in a lab.

This study was too small for us to draw conclusions about the way too little sleep might relate to diabetes. But it does seem like a good reason for all of us to make sure we are getting enough sleep. This may be especially important for people who are overweight, or who have pre-diabetes or diabetes.

More News in Brief

Injections Contaminated by Fungus Have Sickened Hundreds. Between September 18 and October 23, at least 308 people began treatment for symptoms of fungal meningitis infection. The infections were caused by contaminated steroid medication used for back injections. Fifty-four patients were confirmed to have the infection by laboratory tests; 23 people died from the infection. Approximately 14,000 people received the potentially contaminated injection solution. Almost all of these patients have been reached and notified by public health departments so they can be watched for symptoms.
Most infections have involved the fungus Exserohilum rostratum, but two other fungi, Aspergillus fumigates and Cladosporium, have been found in a small number of cases. Exserohilum rostratum has been found in two unopened vials from the compounding pharmacy that supplied the injection medicine. This pharmacy has been closed and all products have been recalled.

The Centers for Disease Control and Prevention are reporting up-to-date information about the outbreak. The Annals of Internal Medicine and New England Journal of Medicine each released details of the initial reported case and treatment recommendations online (October 17 and October 19).

Smoking Bans Get Health Results Quickly. A study released by the journal Circulation October 29 reported that smoke-free laws are having a beneficial effect on the public health of communities. The results include a 15% decrease in hospitalizations and deaths from heart disease, a 16% decrease in stroke hospitalizations, and a 24% decrease in hospitalizations for asthma and other lung diseases. The study combined results from 45 smaller studies of workplaces, restaurants and bars in the United States, Uruguay, New Zealand, and Germany that had smoke-free laws. These results were seen within two years from the time smoking bans were put in place.

Women Who Quit Smoking Gain 10 Years. In a related study published online by The Lancet October 27, researchers have concluded that women who quit smoking when they are young can add 10 years to their lives. This study from the United Kingdom was based on surveys that asked 1.3 million women about their smoking history and health. A national registry kept track of the women's deaths for more than 12 years. The women were between 50 and 65 years old at the start of the study. Twenty percent were smokers, and 28% were ex-smokers. Two-thirds of all deaths of smokers in their 50s, 60s and 70s appeared to be caused by smoking. Most of the difference between smokers and non-smokers came from smoking-related diseases like lung cancer, chronic lung disease, heart disease and stroke.
Based on this study, we can say that female smokers lose about ten years off their lifespans. Stopping before age 40 avoids more than 90% of the smoking-associated risk for early death. Stopping before age 30 eliminates 97% of smoking-associated risk for early death.

Hip "Resurfacing" Doesn't Compare Well to Total Hip Replacement Surgery. Six years ago orthopedic doctors had high hopes for a new alternative to hip replacement called "hip resurfacing." Unlike hip replacement, this surgery does not replace a large section of the femur (thigh bone). Instead, it places a smooth metal cap over the femur inside the hip joint, replacing a thin layer of bone and cartilage. But earlier this year doubts were raised about the long-term success of this procedure. The Lancet released some detailed information online October 1 about results from this surgery.
Researchers followed more than 430,000 patients who had hip operations. About 32,000 of these surgeries were hip resurfacing procedures. The rest were total hip joint replacements. In the first 5 years after hip resurfacing surgery, more than 6% of women and more than 4% of men needed to have another surgery. Less than 2% of men and women who had traditional total hip joint replacement surgery needed a "re-do" surgery within 5 years. These results are disappointing. Hip resurfacing is probably not an acceptable way to treat hip arthritis, especially for women.

Mary Pickett, M.D. is an Associate professor at Oregon Health & Science University where she is a primary care doctor for adults. She supervises and educates residents in the field of Internal Medicine, for outpatient and hospital care. She is a Lecturer for Harvard Medical School and a Senior Medical Editor for Harvard Health Publications.

More What Your Doctor Is Reading Articles

Update From the Medical Journals: October 2012