GeneXpert MTB/Rif, a New Tool for the Diagnosis of Pulmonary Tuberculosis in Two Municipalities in Brazil
Diagnosis of tuberculosis (TB) is a challenge because sputum smear, the most rapid and inexpensive test, often fails to detect the disease, in around 20 to 30% of cases. Culture of sputum yields a correct diagnosis in up to 90% of cases, but results are only available in 4 to 8 weeks, depending on the method. A new tool (GeneXpert) based on a rapid technique, named polymerase chain reaction (PCR), detects TB in less than 2 hours over 95% of cases, in addition to identification of cases resistant to certain drugs used to treat TB. The test is expensive, but several studies have demonstrated its accuracy, and since most steps are automatized, savings can be expected from human resources work. The aims of our study are (1) to evaluate this tool as a substitute test for sputum smears in routine conditions; (2) evaluate if it is cost-effective, meaning that effectiveness of the test may outweigh the extra cost, and (3) evaluate the acceptability of the test among patients and health care workers.
|Study Design:||Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Open Label
Primary Purpose: Diagnostic
|Official Title:||Pilot Roll Out, Cost-effectiveness and Acceptability of the GeneXpert MTB/Rif for the Diagnosis of Pulmonary Tuberculosis in Two Municipalities in Brazil|
- Number of additional TB cases bacteriologically confirmed during intervention period [ Time Frame: October 2012 (up to 2 years) ] [ Designated as safety issue: No ]
- Costs per detected case [ Time Frame: October 2012 (up to 2 years) ] [ Designated as safety issue: No ]
- Acceptability of test [ Time Frame: October 2012 (up to 2 years) ] [ Designated as safety issue: No ]This will consist in a qualitative study to capture issues of perception, understanding and meaning which are not easily amenable to quantitative approaches. We will assess impacts to patients, health workers (HCW)from a wider perspective through semi-structured interviews with themes such as expectations from the diagnostic process, views on TB and its consequences, main concerns. Regarding HCW, we will use the descriptive flowchart, a specific form of group interview. They are asked to elaborate a flowchart describing all steps the patient takes since he enters the facility his dismissal.
- Number of additional smear negative TB cases bacteriologically confirmed during intervention period [ Time Frame: October 2012 (up to 2 years) ] [ Designated as safety issue: No ]
|Study Start Date:||January 2012|
|Estimated Study Completion Date:||October 2012|
|Estimated Primary Completion Date:||October 2012 (Final data collection date for primary outcome measure)|
Sputum specimens arriving during intervention period will be submitted to this test
Other: GeneXpert MTB/Rif
Automatized PCR for the detection of Mycobacterium tuberculosis, the agent of TB, in sputum samples
Other Name: Intervention period
Active Comparator: Sputum smear
Sputum smears arriving in the laboratory during the observation period will be submitted to the classic routine smear staining
Sputum smears arriving in the laboratory during the observation period will be submitted to the classic routine smear staining. This wuld be the non-intervention arm.
This will consist of a group-randomized pragmatic trial following a stepped-wedge design. The GeneXpert machines will be installed in laboratories of the basic health units in Rio de Janeiro and Manaus, two cities with a high burden of the disease in Brazil. Doctors will prescribe routine tests in the clinics. When sputum specimens arrive in the laboratory, instead of performing smears, the GeneXpert will be performed during the intervention period. If positive, a sputum smear will also be performed. The intervention period will be preceded by an observation period during which routine will be kept unchanged, i.e., only smears will be performed. The observation period will serve as a comparator (control). The investigators will then see how many more cases were detected during the intervention period, and in particular, how many smear-negative cases were detected, compared to the observation period.
A total of 300,000 specimens are expected to be tested with the new technology in 14 laboratories. Laboratories, not individuals, will be randomized.
|Contact: Betina Durovni, MDfirstname.lastname@example.org|
|Laboratories of Rio de Janeiro Health Department||Not yet recruiting|
|Rio de Janeiro, RJ, Brazil, 22000|
|Contact: Betina Durovni|
|Principal Investigator: Betina Durovni, MD|