News in brief - March 27, 2006

Air travel could cause thrombosis - Disparities found in heart care - Infants given combination vaccines more likely to get all their shots - Drug patch approved for depression - Kidney failure rises, but risk of death declines

Air travel could cause thrombosis

The low-pressure and low-oxygen environment during air travel might contribute to the development of deep vein thrombosis in susceptible individuals, according to a report in the March 9 The Lancet.

Studies have found a twofold to fourfold increased risk of thrombosis after air travel, with greater risk associated with longer rather than shorter flights. But the mechanism of clot formation during air travel is unclear, the researchers said. Some think immobilization for long periods could play a role, but flight-specific factors also could contribute.

Researchers measured the concentrations of markers of clotting activation in blood samples from 71 healthy volunteers before, during and immediately after an eight-hour flight. To separate the flight factors from immobilization alone, they compared concentrations in the same individuals at the same time points during eight hours of sitting in a cinema and eight hours of regular daily activities.

The authors found increased concentrations in clotting activation markers during flight compared with the other two situations, especially in participants who had additional risk factors for thrombosis, including those who were carriers of a mutation in the factor V gene or were taking oral contraceptives.

The finding led researchers to conclude that the activation of coagulation that occurs in some people during a long flight indicates that mechanisms in addition to immobilization are at work.

Disparities found in heart care

Older, female and minority patients rushed to community hospitals with acute heart attacks are less likely to be transferred to a larger hospital that offers procedures to immediately open clogged arteries, Duke University Medical Center cardiologists reported at the American College of Cardiology's Annual Scientific Sessions in Atlanta.

The team of cardiologists found that women were 16% less likely to be transferred than men, and, compared with white patients, African-Americans were 31% and Hispanics 47% less likely to be transferred. Also, as the patients' ages increased, so did their chances of not being transferred.

Research has shown that even with the added transfer time, patients with an acute heart attack fare better with artery-opening procedures such as angioplasty or bypass surgery than those treated only with clot-busting drugs.

The researchers reviewed data from nearly 400,000 Medicare and Medicaid patients treated from 2001 to 2003.

The researchers said their findings should give physicians in smaller community hospitals more confidence about transferring these often sicker patients to larger hospitals where they would benefit from artery-opening procedures.

Infants given combination vaccines more likely to get all their shots

Babies given shots containing more than one immunization are more likely to get all of their vaccinations, said several studies presented at the National Immunization Conference in Atlanta this month.

Researchers analyzed data from the Georgia State Medicaid program for infants born between January and September 2003. Those who received at least one shot that contained all the antigens against diphtheria, tetanus, pertussis, hepatitis B and polio were more likely to have received all of their vaccines by age 2. For example, nearly 72% of those who received the five-vaccine combination shot received the full three-dose series of polio immunization, while just over 49% of those who received these shots individually did.

"Results from this study suggest that incorporation of a combination vaccine into the routine immunization schedule for the first year of life may yield improved coverage rates," said Gary S. Marshall, MD, lead author and professor of pediatrics at the University of Louisville, Ky.

This five-immunization vaccine was approved by the Food and Drug Administration in December 2002. GlaxoSmithKline, which funded these studies, markets it as PEDIARIX.

Drug patch approved for depression

The Food and Drug Administration gave its stamp of approval last month to the first transdermal patch that delivers medication to treat major depression.

Selegiline (Emsam) is a monoamine oxidase inhibitor that, at its lowest dose, can be used without the usual dietary restrictions required to avoid hypertensive crises that can occur when this drug is taken orally.

"We believe Emsam will help physicians treat their patients living with this illness through a new and unique delivery system," said Peter R. Dolan, CEO of Bristol-Myers Squibb.

The patch will be available in forms that deliver 6, 9 or 12 milligrams over a 24-hour period, and patients on the 6-mg version do not need to change their diet. Those on higher doses need to avoid tyramine, which is found in aged cheese and tap beer.

The most common adverse events with this delivery system included mild skin reactions where the patch was applied. This drug also should not be used along with other antidepressants.

Kidney failure rises, but risk of death declines

The overall incidence of acute renal failure more than quadrupled from 1992 to 2001, but the rate of in-hospital death for these patients dropped significantly, according to a pair of studies published in the April Journal of the American Society of Nephrology.

One study looked at claims data from the Centers for Medicare & Medicaid Services, finding that acute renal failure among Medicare recipients increased by 11% per year and was more common in those who were older, male and African-American.

"It is essential to study the causes of the increased incidence of ARF," said Jay L. Xue, DVM, PhD, lead author and a researcher with the United States Renal Data System Coordinating Center at the University of Minnesota Medical School.

The other study, which analyzed data from the Nationwide Inpatient Sample run by the Agency for Healthcare Research and Quality, found that, although ARF increased the risk of death in comparison with other medical conditions, mortality rates from 1988 to 2002 declined from 40% to 20% among those who did not require dialysis. Among those who did require this procedure, the death rate declined from 41% to 28%.

"The improvement in survival among patients with severe kidney failure suggests that doctors are getting better at treating these extremely ill patients," said Sushrut S. Waikar, MD, lead author on that paper and a researcher at Harvard Medical School in Boston.