| ||What Your Doctor Is Reading || |
Update From the Medical Journals: June 2010
June 30, 2010
By Mary Pickett, M.D.
Harvard Medical School
What's the latest news in the medical journals this month? Find out what your doctor is reading.
Diabetes Increases Risk for Some Common Cancers
Diabetes appears to be linked with a higher risk for certain cancers. Researchers have been concerned about this fact for some time. Experts from the American Diabetes Association and the American Cancer Society have summarized the evidence so far about this connection. It was published online on June 16 in the journal CA: A Cancer Journal for Clinicians.
The increased cancer risk applies mostly to people who have type 2 diabetes, not type 1. People who have type 2 diabetes have roughly double the risk for liver, pancreas and uterine cancers. Their risk for colon, rectal, breast and bladder cancers is 1.2 to 1.5 times the normal risk.
The reason for the connection is still unknown. One theory is that insulin might trigger or encourage cancer growth. People with type 2 diabetes are exposed to more insulin than normal. They may take insulin medicine or their bodies make more insulin naturally. Another theory is that high blood sugar might impair the body's normal immune response. This could permit a cancer to grow. Finally, risk factors for diabetes, such as obesity, may explain part of the increased risk.
Some research suggests that insulin treatment raises cancer risk. More research is needed in this area. But these experts agree that the medicine metformin (Glucophage) seems to reduce some of the excess cancer risk. (Metformin lowers insulin resistance and helps to control blood sugar.)
People with diabetes should have cancer screening tests at the usual recommended ages, including colon cancer screening and mammograms after age 50.
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NSAID Pain Relievers May Raise Heart Attack and Stroke Risk
The drug rofecoxib (Vioxx) was taken off the market in the United States in 2004. It seemed to cause heart attacks and strokes. Since then, medical experts have wondered whether other pain medicines might also cause these harms. Now, one large study provides some answers. It suggests that some non-steroidal anti-inflammatory pain relievers (NSAIDs) are indeed linked to a small increase in strokes or death from heart disease. The study was published June 8 in the journal Circulation: Cardiovascular Quality and Outcomes.
Why would NSAIDS increase heart and stroke risk in people who use them? In the case of Vioxx, the drug made the blood more likely to clot. Other NSAIDs seem to raise blood pressure slightly, which is a fairly common side effect of these drugs. The people in the study were age 39 on average, so overall the number of strokes, heart events and deaths was small. For example, about 1 in 1,000 people taking diclofenac died of heart or blood vessel disease.
The study was not a randomized trial and does not prove that the medications caused the increase in heart and stroke events. It is possible that the people who took the drugs were less healthy to begin with compared with people who did not take them. Nevertheless, the study findings should lead to further safety research.
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Updated Guideline for Diabetes Says Only High Risk Adults Should Take Aspirin
Heart and artery disease risk is two to four times higher in people with diabetes. In fact, 68% of deaths in people with diabetes after age 65 are from heart attacks; 16% are from strokes. The American Diabetes Association (ADA), the American Heart Association (AHA) and the American College of Cardiology Foundation (ACCF) released new recommendations for aspirin use among adults with diabetes. The new guidelines were published online by three journals on May 27: The Journal of the American College of Cardiology, Diabetes Care and Circulation: Journal of the American Heart Association.
People who have the highest risk for heart attack or stroke are people who have already had one attack. Aspirin can reduce risk for a second heart attack or stroke. This is called "secondary prevention." When we use aspirin to prevent a first heart attack or stroke, it is called "primary prevention."
Using aspirin for secondary prevention has clear benefits. But the benefits for primary prevention have been less certain. That's because the risk of bleeding complications from aspirin has the potential to outweigh aspirin's benefits. The main concern is bleeding from the intestine or hemorrhage after head injury.
Several recent randomized studies, however, have provided new information about the benefits and risks of aspirin for people who have never had a first heart event or stroke. These led to the new recommendations from the ADA, AHA and ACCF, which now restrict aspirin for primary prevention to adults who are older and have an increased risk for cardiovascular disease. Adults who have diabetes but no history of prior vascular disease qualify for aspirin therapy only if they are at particularly high risk for a cardiovascular event in the next ten years. This means that most men older than 50 and most women older than 60 are considered high risk only if they also have one or more of these major risk factors: smoking, hypertension, bad cholesterol, a family history of heart disease at an early age or protein in the urine from diabetic kidney disease. The guidelines recommend choosing a low dose of aspirin (75 to 162 milligrams per day).
Doctors do not recommend aspirin for primary prevention to these higher risk individuals if they have a peptic ulcer history or a risk of bleeding from regular use of NSAID drugs like ibuprofen).
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More News in Brief
- Prescription Drug Abuse is Increasing Among Teens and Other Americans. According to a reliable survey, one-fifth of U.S. high school students are taking prescription drugs that weren't prescribed for them. Use was highest among 12th graders: About one in four seniors said they had used a drug without a prescription. Some of the prescription drugs that teens use for experimentation, performance boosting or "getting high" include narcotics such as Oxycontin and Percocet, stimulants such as Adderall and Ritalin, and anxiety drugs such as Xanax. The U.S. Centers for Disease Control and Prevention (CDC) released the survey results on June 3. The Youth Risk Behavioral Survey is given every two years to high school students across the United States. In 2009, more than 16,000 students answered questions about health risk behaviors. The survey was comprehensive. In addition to drug use, it asked about sex, diet and exercise habits. In a separate survey published by the CDC June 17 in the Morbidity and Mortality Weekly Report (MMWR), for the first time, abuse of prescription drugs is resulting in a larger number of emergency department visits each year than abuse of illegal drugs, such as cocaine, heroin and methamphetamine. These data came from a sampling of emergency room visits between 2004 and 2008. Doctors prescribing drugs with potential for abuse are obligated to monitor their patients carefully, and confirm that the medications are being used as they are prescribed.
- Blood-Clot Drug Improves Accident Survival. On June 15 the Lancet published a study that could change trauma care. The British government funded the study to test the drug tranexemic acid (TXA). The drug speeds the formation of blood clots at the site of a wound. Emergency response crews in more than 40 countries participated. More than 10,000 patients were given the drug within eight hours of being injured in serious accidents. Another similar group of patients was given a placebo drug after their injuries. The group that received the drug had a 15% lower rate of death from hemorrhage. They also had a 10% lower chance of dying from any other cause. This surprised some experts, who had been concerned that the drug might trigger unwanted clots. This could caus complications such as heart attacks or blood clots in the leg or lungs. These complications were not seen in this short-term study. The drug is already available as a generic medication and is inexpensive. Based on the results of this study, it is likely that this drug will be widely used to improve survival after serious trauma.
- New Drug for Diabetes Removes Excess Blood Sugar Through Urine. A promising new medicine for diabetes may soon be available. Short-term studies of safety are showing good results. The drug is called dapagliflozin. It lowers blood sugar levels by causing unusually large amounts of sugar to spill into the urine. But this drug does not correct the abnormal metabolism that causes diabetes. It also does not make glucose more available to the body as a fuel source. So it would not be an appropriate treatment alone for most diabetics. Lower blood sugar levels may help lower complications of diabetes. But more studies are needed to confirm this. A welcome side effect of the drug is weight loss. A report about the drug was released online by Lancet on June 24.
- Antiviral Drugs Limit Spread of HIV. The Lancet released study results online on May 26 showing that treating HIV infected persons with antiviral medicines reduced the spread of HIV through sex by 92%. This study only evaluated heterosexual sex. The 3,381 couples in the study were followed for 24 months. It was not a randomized study. Instead, researchers checked health records for couples where one person was infected with HIV and the other person was not infected. They took note of which HIV patients were receiving antiviral drugs. The couples were advised to use condoms whether or not the infected partner was taking antiviral treatment.
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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.