Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Women’s high heart-surgery death rate may be due to infection

28.02.2006


Mystery of why women die more often than men after bypass operations may be rooted in preventable or treatable causes



For years, experts have puzzled over the fact that women who have heart bypass surgery are far more likely than their male counterparts to die within days or weeks of their operation. This gender gap means many "extra" female deaths among the 270,000 Americans who have bypass surgery each year.

Now, a new University of Michigan study suggests that the answer to the mystery may lie with infections, regardless of their location in the body.


In a paper in the Archives of Internal Medicine, U-M Health System researchers report that 96 percent of the gender difference in death risk within 100 days of coronary artery bypass surgery may be explained by differences in infection. They used hospital and post-hospital data from 9,218 Michigan residents who had bypass surgery in a 15-month period. All were Medicare beneficiaries age 65 years or older.

"Overall, we found that women’s increased risk of mortality after coronary artery bypass surgery may be due to differences in infection," says lead author Mary A. M. Rogers, Ph.D., M.S., research director of the Patient Safety Enhancement Program of the U-M Health System and the Veterans Affairs Ann Arbor Healthcare Center. "We found that 16 percent of women patients had an infection, compared with 10 percent of men." This difference persisted after taking into account age, race, urgency of the operation, length of hospital stay, most co-existing medical conditions, and the number of bypass operations performed at each hospital or by each surgeon.

"We suspect that there may be a systemic, or body-wide, response to infection, making infection at any site a concern in elderly patients," Rogers continues. She notes that women in the study were more likely than men to have infections of the urinary, respiratory and digestive tracts. Women were also more likely than men to have skin and post-operative infections.

But this was not the study’s only finding. Although women who had heart surgery were much more likely to have an infection than their male counterparts, women with an infection were less likely to die than men who had an infection. "This finding was a surprise since, overall, women had greater mortality," says Rogers. "But when we looked closer, we found that there were two underlying relationships here: a greater prevalence of infection in women, and a higher mortality once infected for men."

This pattern of greater morbidity in women but greater mortality for men has been observed before in elderly populations, Rogers notes. "Women tend to live with their disease; men die of it," she says. In this case, the overall mortality was higher in women because infections were so much more prevalent among them.

In all, about 12 percent of patients in the study who had infections during their hospital stay died before leaving the hospital, compared with 4 percent of those without infections. And when the researchers looked at who had died in the first 30 and 100 days after their operation, those who had had an infection in the hospital were still far more likely to die.

Now, Rogers says, further research is needed to determine if any patient-related factors not analyzed in the study, such as blood-sugar control, nutritional status, smoking and genetic factors related to infection susceptibility, may account for these findings -- and what role hospital-related factors such as the use of catheters might play. "There has been research indicating that, in patients undergoing heart surgery, small body size is a risk factor for mortality," says Rogers. "So, there is a need for additional studies in this area."

Until the new results can be confirmed and the precise role of infection in the bypass surgery "gender gap" determined, Rogers and her co-authors say there is much that heart patients of both sexes can do to prevent pre- and post-operation infections. Elderly Americans should keep up-to-date with their yearly influenza vaccination and, every five years, be vaccinated against bacterial pneumonia. Both vaccinations could be life-saving.

While in the hospital, bypass patients should heed their doctors’ advice to get up and start walking the hospital floor after their operation, because staying in bed for long periods of time may encourage respiratory infections. Frequent hand-washing by patients and their hospital caregivers is a good idea, and patients might also consider asking friends and family members who have colds to send their wishes by phone or computer instead of visiting.

Appropriate use of antibiotics is also important in patients undergoing bypass surgery. In fact, current national guidelines for bypass surgery call for patients to receive antibiotics an hour before their operation begins and to stay on them for at least a day afterward. The data used by Rogers and her colleagues did not include information regarding medications, so any differences among men and women in antibiotics use could not be evaluated.

Rogers, a faculty member in the General Medicine division of the U-M Department of Internal Medicine, works with a range of U-M physicians and researchers who study various aspects of patient safety and health care quality. That cooperation is what led to the current study. She had been working with Sanjay Saint, M.D., MPH, director of the Patient Safety Enhancement Program and associate professor of general medicine at the U-M and VA, on projects related to urinary tract infections among hospitalized patients with catheters. At the same time, she was working with heart-care quality researchers Brahmajee Nallamothu, M.D., MPH, and Catherine Kim, M.D., MPH, to examine differences among women and men in heart disease and care.

Curious to see if research had ever been done on the role of infection in heart-related gender differences, Rogers explored the medical literature -- and found little. So, she embarked on the study with her colleagues, using Medicare data from a project led by Ken Langa, M.D., Ph.D., assistant professor of general medicine and a member of the U-M Institute for Social Research.

Kara Gavin | EurekAlert!
Further information:
http://www.umich.edu

More articles from Health and Medicine:

nachricht NIST scientists discover how to switch liver cancer cell growth from 2-D to 3-D structures
17.11.2017 | National Institute of Standards and Technology (NIST)

nachricht High speed video recording precisely measures blood cell velocity
15.11.2017 | ITMO University

All articles from Health and Medicine >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: A “cosmic snake” reveals the structure of remote galaxies

The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.

Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...

Im Focus: Visual intelligence is not the same as IQ

Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.

That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...

Im Focus: Novel Nano-CT device creates high-resolution 3D-X-rays of tiny velvet worm legs

Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.

During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....

Im Focus: Researchers Develop Data Bus for Quantum Computer

The quantum world is fragile; error correction codes are needed to protect the information stored in a quantum object from the deteriorating effects of noise. Quantum physicists in Innsbruck have developed a protocol to pass quantum information between differently encoded building blocks of a future quantum computer, such as processors and memories. Scientists may use this protocol in the future to build a data bus for quantum computers. The researchers have published their work in the journal Nature Communications.

Future quantum computers will be able to solve problems where conventional computers fail today. We are still far away from any large-scale implementation,...

Im Focus: Wrinkles give heat a jolt in pillared graphene

Rice University researchers test 3-D carbon nanostructures' thermal transport abilities

Pillared graphene would transfer heat better if the theoretical material had a few asymmetric junctions that caused wrinkles, according to Rice University...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Ecology Across Borders: International conference brings together 1,500 ecologists

15.11.2017 | Event News

Road into laboratory: Users discuss biaxial fatigue-testing for car and truck wheel

15.11.2017 | Event News

#Berlin5GWeek: The right network for Industry 4.0

30.10.2017 | Event News

 
Latest News

Antarctic landscape insights keep ice loss forecasts on the radar

20.11.2017 | Earth Sciences

Filling the gap: High-latitude volcanic eruptions also have global impact

20.11.2017 | Earth Sciences

Water world

20.11.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>