Update From the Medical Journals: August 2012
August 31, 2012
By Mary Pickett, M.D.
What's the latest news in the medical journals this month? Find out what your doctor is reading.
Test results to check for a heart attack can be normal within the first few hours after an attack. So, if doctors suspect a possible heart attack, they watch and closely monitor patients for 12 to 16 hours in an emergency room or hospital.
Doctors mainly use two tests to tell whether a person is having a heart attack: the electrocardiogram (ECG) and a cardiac troponin blood test. Troponin is released into the blood stream when heart muscle cells are injured. To rule out a heart attack, doctors may repeat a troponin test every 6 to 8 hours.
Now there's a new troponin test that is much more sensitive. It's called a high-sensitivity troponin test. It can detect heart damage much sooner after symptoms start.
A study in the August 13 issue of Archives of Internal Medicine reported the results of a new faster approach to diagnosing heart attacks. Researchers used the usual ECGs. They also used the new high-sensitivity troponin test.
Instead of waiting 6 to 8 hours between tests, they did a high-sensitivity troponin blood test when the patient arrived and repeated it in 1 hour. If the test result was normal and the troponin did not increase from the first to the second test, it was safe to say the patient didn't have a heart attack. Using this method, the researchers ruled out heart attack in 60% of patients. They found evidence of heart attack in 17%. And the other 23% of patients were observed and monitored further.
The Swiss study took place from April 2006 to June 2009. It included almost 900 patients who visited the ER with chest pain.
If you are overweight, you are more likely to have diabetes. And if you have diabetes, losing weight can improve your health. But about 12% of people with type 2 diabetes have a normal body mass index (a normal weight, adjusted for height) at the start of their diabetes. A new study finds that these people are more likely to die early compared with people who are overweight when they are diagnosed with diabetes. The Journal of the American Medical Association published the study August 8.
Researchers combined the results from 5 long-term studies. They included 2,600 people with diabetes. They were all over age 40. During follow-up, about 450 people died. Researchers adjusted the numbers to account for other factors, such as smoking, that affect death risk. They found that death rates during the study were 2.32 times higher among people who were not overweight when diagnosed.
One way doctors can explain this finding is by looking at body shapes. People with diabetes who have a normal body mass index are not necessarily "thin." They may have a normal weight (for their height), but still have belly fat that expands their waistlines. Doctors have known that belly fat (also called visceral fat) causes more problems for metabolism than fat in the hips, buttocks, thighs and upper arms. In this case, fat is also found inside internal organs, such as the liver.
Belly fat increases your risk of heart disease, stroke and other blood vessel diseases, in addition to diabetes. From a risk standpoint, if your BMI is high, you're better off not carrying the fat around your waist. In this study, overweight and even slightly obese people with diabetes who had a reasonable waist size (and therefore not too much belly fat) lived longer. But people of normal weight with large waists had the highest risk of early death in this study. High blood levels of triglycerides also increased risk. Triglyceride levels tend to be higher in people with more belly fat.
If you have diabetes and your waist size is greater than normal, exercise especially weight training to build more muscle mass is especially important.
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.