7.2 History of prior anti-TB treatment

Patients who have interrupted or failed a previous anti-TB treatment have a higher risk of developing drug resistance (DR). Therefore, it is important to question patients about their previous treatment prior to treatment initiation.

Case registration distinguishes between1:

New patients: patients who have never been treated for TB or have taken anti-TB drugs for less than 1 month.

Previously treated patients: patients who have received 1 month or more of anti-TB drugs in the past.
Previously treated patients are further sub-classified into relapse, failure and return after treatment interruption:
Relapse: patients who were cured or completed treatment on their last TB treatment;
 Failure: patients who have failed their most recent treatment (see Chapter 17 for outcome definitions for failure);
 Treatment interruption: patients who interrupted (see Chapter 17 for outcome definition of treatment interruption) their last treatment should be classified as “Return after treatment interruption”.

Others: patients who cannot be included in one of the above categories (e.g., patients who have previously been treated via an erratic or unknown TB regimen).