Health costs could be reduced by more appropriate use of cardiac stress testing with imaging

In a new study recently published in the Annals of Internal Medicine, researchers at NYU Langone Medical Center concluded that overuse of cardiac stress testing with imaging has led to rising healthcare costs and unnecessary radiation exposure to patients.

In what is believed to be the first comprehensive examination of trends in cardiac stress testing utilizing imaging, researchers also showed that there are no significant racial or ethnic health disparities in its use. They also made national estimates of the cost of unnecessary cardiac stress testing with imaging and the health burden of this testing, in terms of cancer risk due to radiation exposure.

Cardiac stress testing, particularly with imaging, has been the focus of debate about rising health care costs, inappropriate use, and patient safety in the context of radiation exposure. Joseph Ladapo, MD, PhD, assistant professor in the Departments of Medicine and Population Health at NYU Langone, and the lead author of the study, and colleagues wanted to determine whether U.S. trends in cardiac stress testing with imaging may be attributable to population shifts in demographics, risk factors, and provider characteristics, and to evaluate whether racial/ethnic disparities exist in physician decision making.

They designed their study utilizing data from the National Ambulatory Medical Care Survey (NAMCS) and National Hospital Ambulatory Medical Care Survey (NHAMCS) from 1993 to 2010. Patients chosen for the study were adults without coronary heart disease who were referred for cardiac stress tests.

Between 1993 to 1995 and 2008 to 2010, the annual number of ambulatory visits in the U.S. in which a cardiac stresstest was ordered or performed increased by more than 50%. Cardiac stress tests with imaging comprised a growing portion of all of these tests – increasing from 59% in 1993 to 1995 to 87% in 2008 to 2010. At least 34.6% – or one million tests – were probably inappropriate, the researchers concluded, with associated annual costs and harms of $501 million and 491 future cases of cancer.

The authors also concluded that there was no evidence of a lower likelihood of black patients receiving a cardiac stresstest with imaging (odds ratio, 0.91 [95% CI, 0.69 to 1.21]) than their white counterparts – although some modest evidence of disparity in Hispanic patients was found (odds ratio, 0.75 [CI, 0.55 to 1.02]).

The investigators concluded that the national growth in cardiac stress testing can be attributed largely to population and provider characteristics – but the use of imaging cannot. Physician decision making about cardiac stress testing also does not result in racial/ethnic disparities in cardiovascular disease.

“Cardiac stress testing is an important clinical tool,” says Dr. Ladapo, “but we are over using imaging for reasons unrelated to clinical need. This is causing preventable harm and increasing healthcare costs.

“Reducing unnecessary testing also will concomitantly reduce the incidence of radiation related cancer,” he adds. “We estimate that about 500 people get cancer each year in the US from radiation received during a cardiac stress test when, in fact, they most probably didn’t need any radiological imaging in the first place. While this number might seem relatively small, we must remember that ‘first, do no harm’ is one of the guiding principles in medicine.”

So what can be done to reduce unnecessary cardiac stress testing with imaging? “More efforts, such as clinical decision support, are needed to reduce unnecessary cardiac stress testing,” Dr. Ladapo concludes, suggesting greater use ofstress testing without radiological imaging, such as regular exercise treadmill tests or stress testing with ultrasoundimaging as opposed to CT imaging.

As to the reason why certain racial and ethnic minorities have poorer rates of treatment for cardiovascular disease and generally have poorer cardiovascular health outcomes compared to white patients, Dr. Ladapo concludes that no one has really explored whether there could be disparities in cardiac stress testing, which is a mainstay of diagnosing patients with heart disease in this country. “If we know that one minority group has a higher incidence of poorer outcomes from heart disease, perhaps we need to examine if they would benefit from more appropriate use of cardiac stress testing,” he offers. “Perhaps one contributing reason they have poorer outcomes is because we are not testing them appropriately.”

http://www.medicalnewstoday.com/releases/283694.php

 

Exercise can enhance tumor-shrinking effects of chemotherapy

New research published in the American Journal of Physiology, suggests exercise may boost the tumor-shrinking effects of chemotherapy.

In a study of mice with melanoma, scientists from the University of Pennsylvania (Penn) in Philadelphia, found that chemotherapy shrank more tumors when combined with exercise.

Senior author Joseph Libonati, an associate professor in Penn’s School of Nursing, and colleagues were originally trying to find out if exercise could protectcancer patients against the heart damage that can result from use of the common cancer drug doxorubicin.

Although the drug is effective against a variety of cancers, one of its side effects is the potential damage it can do to heart cells. In the long term, this can causeheart failure.

Prof. Libonati says at first, all cancer patients are concerned about is the cancer, “and they’ll do whatever it takes to get rid of it.”

“But then when you get over that hump you have to deal with the long-term elevated risk of cardiovascular disease,” he adds.

There is evidence that taking up regular exercise before undergoing chemotherapy can protect heart cells from the damaging effects of doxorubicin. But not many have investigated whether there is any benefit from exercising during chemotherapy.

For their study, the team picked four groups of mice and induced them with melanoma. Over the next 2 weeks, two of the groups received two injections of doxorubicin, and two received placebo injections.

At the same time, mice in one of the chemotherapy groups and one of the placebo groups were placed on exercise regimens. The other mice did not exercise during the treatment period. The exercising mice walked on treadmills for 45 minutes a day on 5 days of each week.

Exercise helped chemotherapy shrink tumors but did not change effect on heart

After the 2-week period, the team found the mice that received chemotherapy – regardless of whether they had exercised or not – showed signs of heart damage. The damage consisted of reduced heart function and increased fibrosis or tissue thickening.

As Prof. Libonati says, “exercise didn’t do anything to the heart – it didn’t worsen it, it didn’t help it.”

But he and his team were amazed when they looked at the tumors. They found the mice that had received chemotherapy and exercised had much smaller tumors after 2 weeks than the sedentary mice on chemotherapy.

They conclude that in mice with melanoma, exercise appears to boost the tumor-shrinking effects of doxorubicin, without having an effect on the damage the drug can do to the heart.

They suggest further studies should now look into exactly how exercise boosts the effects of chemotherapy. Perhaps a reason is because exercise improves blood flow, which allows more of the drug to reach the cancer cells.

Prof. Libonati adds, “If exercise helps in this way, you could potentially use a smaller dose of the drug and get fewer side effects.”

He explains that we are only just beginning to understand the effect exercise can have on drug- taking:

“People don’t take a drug and then sit down all day. Something as simple as moving affects how drugs are metabolized.”

Finding out more about how exercise affects the body could lead to drugs that mimic the effects of exercise.

Funds for the study came from the National Cancer Institute, the National Heart Lung and Blood Institute, the National Center for Research Resources, the National Center for Advancing Translational Sciences, and the Biobehavioral Research Center at Penn.

Meanwhile, Medical News Today recently learned of a study published in Science Translational Medicine that showed how tumors shrank following a bacteria injection. The researchers shrank cancer tumors in rats, dogs and also one human patient, by directly injecting the tumors with a modified version of Clostridium novyi to trigger targeted anti-cancer responses.

Written by Catharine Paddock PhD

Copyright: Medical News Today

http://www.medicalnewstoday.com/articles/282767.php