Tuberculosis in China
Condition: Tuberculosis; Tuberculosis, Multidrug-Resistant; Extensively Drug Resistant Tuberculosis
MeSH terms: Tuberculosis; Tuberculosis, Multidrug-Resistant; Extensively Drug-Resistant Tuberculosis
Study type: Observational

Summary: 
      Background:

      - In spite of well-researched treatments and therapies, 5 to 10 percent of tuberculosis (TB)
      patients who have initially successful TB treatments will relapse, usually within a year
      after completion of therapy. This percentage is even greater for patients who are infected
      with multi-drug resistant and extensively drug resistant types of TB. Because the People s
      Republic of China has the second highest number of TB cases in the world, researchers are
      interested in studying TB patients in China to evaluate their response to treatment on a
      long-term basis.

      Objectives:

        -  To improve TB diagnosis and testing by determining the number and proportion of patients
           admitted with suspected TB who actually have TB (definite or probable).

        -  To assess the prevalence of non-tuberculosis bacteria among patients with presumed TB.

      Eligibility:

      - Individuals between 18 and 65 years of age who have been admitted to Henan Provincial Chest
      Hospital with suspected tuberculosis.

      Design:

        -  Participants will be divided into three groups, based on their diagnosis after
           admission. Another group of individuals who do not have TB will be enrolled as controls
           for comparison purposes during the study.

        -  The study will use computed tomography (CT) scans of the chest at initial enrollment, 2
           months, and 6 months to evaluate disease response to treatment. Incidents of TB that are
           not in the chest area (extrapulmonary TB) will also be studied.

        -  The study will also monitor the treatments and therapies used against the disease,
           changes in patients immune systems, and any changes in the biological samples taken over
           the course of treatment.
    

Detailed description: 
      Despite optimal antimicrobial treatment with directly observed short-course therapy (DOTS),
      about 5-10 percent of drug-compliant patients with cured tuberculosis (TB or MTB) relapse,
      usually within a year after completion of therapy. This percentage is even greater for
      patients that have previously been treated for TB who often are infected with multi-drug
      resistant (MDR) and extensively drug resistant (XDR) organisms. The People s Republic of
      China has the second highest number of cases of TB in the world, with a rate of 101
      cases/100,000 person-years estimated for 2004. Based on the data of the 4th national TB
      epidemiological survey in 2000, it is estimated that there were 1.96 million instances of
      pulmonary TB. With an established MDR TB prevalence of 10.7 percent, there were an estimated
      209,720 cases of pulmonary, bacteriology confirmed MDR TB in China in 2000. About half of all
      prevalent cases of TB disease in 2000 were extrapulmonary.

      This prospective longitudinal natural history study will monitor 150 subjects with suspected
      TB at the Henan Provincial Chest Hospital during their initial response to antituberculous
      chemotherapy. The subjects will be divided into 3 groups of TB-infected individuals: Cohort
      A) acid-fast bacilli (AFB) smear positive pulmonary disease; Cohort B) smear negative
      pulmonary disease; and Cohort C) extra-pulmonary disease (EPTB) in order to reflect the
      spectrum of TB manifestations observed at Henan Provincial Chest Hospital. We will also be
      enrolling 45 non-TB suspects as controls (Cohort D). The control group will serve as a
      comparison group for exploratory immunologic and diagnostic assays that may, in the future,
      serve as ways to diagnose TB and/or evaluate response to therapy.

      In this exploratory study, we will be looking at the change in total volume of disease as
      detected by computerized tomography scans of the chest at baseline, at 2 months, and at 6
      months. We will also be looking at scanned regions of extrapulmonary TB. In addition, we will
      monitor chemotherapeutic regimen, changes in the host immune response, overall changes in
      clinical parameters, initial and acquired drug-resistance of the infecting isolates, and
      changes in bacterial and host markers in subject samples during chemotherapy. In each case,
      we will look for associations of these parameters with rates of disease resolution correlated
      with specific structural features determined by computerized tomography scanning of the sites
      of TB disease (with the exception of TB meningitis and cutaneous TB, for which there are no
      specific lesions to follow radiographically). These studies will allow us to evaluate the use
      of entry criteria in future clinical trials and eventual TB diagnosis confirmation using
      these entry categorizations. We will also be able to examine the impact of initial regimen
      selection, and subsequent modifications, mycobacterial strain characteristics, extent of
      disease, types of lesions and host immunologic response to the overall outcome of
      chemotherapy, as well as potentially identify surrogate markers for improving monitoring of
      the response to chemotherapy.
    

Time perspective: Prospective
Keywords: Biomarkers; Extrapulmonary TB; NTM; HRCT; MDRTB; Tuberculosis