MDR-TB Definitions

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Cordt Byrne
Last updated: Sept 01, 2011Version comment
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These definitions are taken from the WHO's Guidelines for the programmatic management of drug-resistant tuberculosis document. Refer to Section 1, Chapter 4, page 19 of the document for a more detailed explanation of each key term.

Bacteriology Status

  • Conversion - is defined as two sets of consecutive negative smears or cultures, from samples at least 30 days apart (with no further positive results afterwards).

MDR-TB Diagnosis Site

This is entered in the encounter for the intake visit.

  • Pulmonary - Tuberculosis involving only the lung parenchyma.
  • Extrapulmonary - Tuberculosis of organs other than the lungs.
  • Note: Patients with both pulmonary and extrapulmonary TB should be classified as under Pulmonary. 

Program Outcome

  • Patient Transferred Out - Select this outcome for a patient who has been transferred to another reporting and recording unit and for whom the treatment outcome is unknown.
  • Regimen Failure - Treatment will be considered to have failed if two or more of the five cultures recorded in the final 12 months of therapy are positive, or if any one of the final three cultures is positive. Treatment will also be considered to have failed if a clinical decision has been made to terminate treatment early because of poor clinical or radiological response or adverse events.
  • Treatment Complete - A Category IV patient who has completed treatment according to program protocol but does not meet the definition for cure because of lack of bacteriological results (i.e. fewer than five cultures were performed in the final 12 months of treatment).
  • Patient Defaulted - A Category IV patient whose treatment was interrupted for two or more consecutive months for any reason without medical approval.
  • Patient Died - A Category IV patient who dies for any reason during the course of MDR-TB treatment.
  • Patient Cured - A Category IV patient who has completed treatment according to program protocol and has at least five consecutive negative cultures from samples collected at least 30 days apart in the final 12 months of treatment. If only one positive culture is reported during that time, and there is no concomitant clinical evidence of deterioration, a patient may still be considered cured, provided that this positive culture is followed by a minimum of three consecutive negative cultures taken at least 30 days apart.

Registration Group - Previous Drug Use

  • New MDR TB patient - This is the first time the patient has taken TB drugs or if the patient has received less than one month of antituberculosis treatment.
  • Previously treated with first line drugs only - The patient previously took RHEZ or RHEZ + S for more than one month.
  • Previously treated with second line drugs - The patient has previously been on an MDR TB regimen.

Registration Group - Previous Treatment

  • New - The patient has never received treatment, or if the patient has received less than one month of treatment at the time of collection of the sputum sample that was used to confirm MDR-TB.
  • Relapse - The patient previously completed treatment, and the outcome of the previous treatment was “cured” or “treatment completed”.
  • Patient Defaulted - Patients who are returning to treatment following an interruption of treatment for two or more consecutive months.
  • Treatment after failure of Category I Treatment MDR TB patient - The patient failed treatment after taking RHEZ
  • Treatment after failure of Category II Treatment MDR TB patient - The patient failed treatment after taking second line drugs.
  • Transfer - The patient is transferring from another site where they were taking Category IV treatment.
  • Other Non-Coded - Patients who do not fit into any of the given categories.

Resistance Type

The resistance type is calculated automatically based on the patient’s Drug Sensitivity Test results.

  • Confirmed Mono-resistant TB - Resistance to one antituberculosis drug.
  • Confirmed Poly-resistant TB - Resistance to more than one antituberculosis drug, other than both isoniazid and rifampicin. If resistant to both INH and R, see below.
  • Confirmed MDR-TB - Resistance to at least isoniazid and rifampicin.
  • Extensive Drug Resistance - Resistance to any fluoroquinolone, and at least one of three injectable second-line drugs (capreomycin, kanamycin and amikacin), in addition to multidrug-resistance.

Type of Treatment Change

  • Standardized - Treatment is based on DRS (drug resistance surveillance) data from representative patient populations. No individual history or DST is available/considered.
  • Empiric - The regimen is based on the patient’s previous history of antituberculosis treatment without individual DST information.
  • Individualized - The regimen is based on the patient’s previous history of antituberculosis treatment and individual DST results.