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Half of extensively drug-resistant TB patients die [AlertNet]

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  • Half of extensively drug-resistant TB patients die [AlertNet]

    Half of extensively drug-resistant TB patients die [AlertNet]
    Half of extensively drug-resistant TB patients die

    06 Nov 2008 05:00:21 GMT
    Source: Reuters
    By Will Dunham
    WASHINGTON, Nov 6 (Reuters) -

    The hardest-to-treat form of tuberculosis kills half the people who get it, according to a South Korean study that is one of the few to track survival rates from the condition called extensively drug-resistant TB.


    Tuberculosis is an infectious bacterial disease typically attacking the lungs.

    Increasing numbers of cases of TB that defy standard medical treatment are appearing worldwide.

    The study tracked 1,407 patients with two categories of TB: multidrug resistant TB, or MDR-TB, which resists at least one of the two main TB drugs, and extensively drug-resistant TB, or XDR-TB, which defies nearly all drugs used to treat TB.

    Forty-nine percent of those with XDR-TB died compared to 19 percent of patients with ordinary MDR-TB, researchers led by Dr. Tae Sun Shim of Asan Medical Center in Seoul wrote on Thursday in the American Journal of Respiratory and Critical Care Medicine.

    The patients were diagnosed between 2000 and 2002 and were followed for up to seven years, the researchers said. About 5 percent of the patients had XDR-TB.

    D'Arcy Richardson of the Seattle-based nonprofit group PATH, which supports public health efforts in about 70 nations, called the findings important. But she noted XDR-TB patients today likely would get more aggressive drug treatment than was given to the patients tracked in this study.

    "We have so little information on XDR-TB to begin with," Richardson, who wrote a commentary with two other TB experts accompanying the study, said in a telephone interview.

    Cases of drug-resistant tuberculosis are being recorded around the world at the highest rates ever, with parts of the former Soviet Union especially vulnerable, the U.N. World Health Organization said this year.

    Such cases account for about 5 percent of the 9 million new TB cases annually, the WHO said. It said that 489,139 MDR-TB cases emerged in 2006, and about 40,000 were XDR-TB.

    There has been scant scientific data on long-term survival rates from XDR-TB.

    "We know that it's a very big problem in Eastern Europe. We know it's a very big problem in Asia, particularly in India and China, where they don't necessarily have large percentages of MDR and XDR but because of the size of the population with TB we have significant numbers," Richardson said.

    TB killed 1.7 million people worldwide in 2006, the WHO said. It can be spread by breathing in air droplets from a cough or sneeze of an infected person.

    (Editing by Julie Steenhuysen and Xavier Briand)
    -
    <cite cite="http://www.alertnet.org/thenews/newsdesk/N05313913.htm">Reuters AlertNet - Half of extensively drug-resistant TB patients die</cite>

  • #2
    Re: Half of extensively drug-resistant TB patients die [AlertNet]

    XDR-TB: Deadlier and more mysterious than ever [EurekAlert]
    XDR-TB: Deadlier and more mysterious than ever

    New research has found that XDR-TB is increasingly common and more deadly than previously known. Extensively drug-resistant tuberculosis (XDR-TB) is a growing public health threat that is only just beginning to be understood by medical and public health officials.


    Patients with XDR-TB are four times as likely to fail treatment and three times more likely to die than patients with other forms of multi-drug-resistant TB (MDR-TB), according to a recent study that directly compared patients with XDR-TB to individuals with other types of MDR-TB to determine the differences in treatment outcomes and long-term survival rates.

    Researchers also found that MDR-TB was "a major threat to public health," representing 2.7 percent of new TB cases in South Korea in 2004, up from 1.6 percent in 1994.

    The results were published in the second issue for November of the American Journal of Respiratory and Critical Care Medicine, a journal of the American Thoracic Society.

    Since it appeared on the public health radar in 2006, XDR-TB rekindled an urgent interest in preventing, fighting and containing TB. But at the same time, little was known about how XDR-TB changed the face of combating TB on all fronts, from the perspective of the patient, the clinician and the public health official.

    "Treatment outcomes [of XDR-TB] have varied among studies, and data on long-term survival are still scarce," wrote Tae Sun Shim, M.D., an associate professor at Asan Medical Center in Seoul, South Korea, and a principal investigator of the study. "[This] is the largest report that we know of that compares patients with XDR-TB with other patients with MDR-TB to determine the impact of XDR-TB on treatment outcomes and long-term survival in mostly HIV-negative patients with MDR-TB."

    The study reviewed the medical records of more than 1,400 patients in South Korea with MDR-TB (which includes XDR-TB) from all national hospitals, Korean National TB Association chest clinics and select university hospitals. In addition to the patients' demographic information, their history of TB and previous treatments were noted with regard to outcome. In this study, XDR-TB was defined as MDR-TB resistant to both ofloxacin and at least one second-line injectable drug.

    The researchers found that patients with XDR-TB were significantly older than MDR-TB patients, were more likely to have a history of treatment with second-line TB drugs, and more likely to have a history of being treated for TB two or more times.

    Among this population, treatment failure was, not surprisingly, much more common when compared to other patients with MDR-TB. While relapse rate among "cured" patients also tended to be higher among patients with XDR-TB, the difference was not statistically significant.

    "[Having] XDR-TB was the strongest predictor of both all-cause and TB-related mortality, and survival curves showed higher cumulative mortality among patients with XDR-TB than in other patients with MDR-TB," wrote Dr. Shim. Over the three to seven years that the study's patient population was monitored, approximately 50 percent of those identified with XDR-TB died, which was a mortality rate similar to untreated TB patients in South India, and one that becomes even worse with HIV co-infection.

    Perhaps the biggest public health threat associated with XDR-TB, however, is not its particular virulence, but the lack of information and treatment options that medical and public health officials have on which to draw. The collective dearth of knowledge was likened by Giovanni Battista Migliori, M.D., Morgan Richardson, R.N., P.H.N., and Christopher Lange, M.D., Ph.D., co-authors of the accompanying editorial, to the proverbial blind men trying to describe an elephant?too big a task to accomplish with too little information.

    The risks of this lack of information are clear.

    "Regrettably, a new drug [to treat TB] has not been licensed in decades," they wrote, saying that only further research and concerted effort to understand and quantify the effects of the disease can really prevent MDR- and XDR-TB from becoming pandemic health crises.

    "As we wait for new diagnostics and drugs that can meet the challenge of XDR-TB, we must work with what we presently have to create the optimal conditions for success and thus seize the opportunity we have to eliminate tuberculosis," they concluded.

    ###
    Full text of original article available here: http://www.thoracic.org/sections/pub...B%20111508.pdf
    Full text of original editorial available here: http://www.thoracic.org/sections/pub...d%20111508.pdf
    -
    <cite cite="http://www.eurekalert.org/pub_releases/2008-11/ats-xda110308.php">XDR-TB: Deadlier and more mysterious than ever</cite>

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