Fig. 1

The pathway model for the standard-of-care strategy. Patients enter the model at time zero and move along their pathways four weeks at a time. At the end of the four-week cycle, the model checks whether week 16, which denotes the end of the intensive phase (IP), has been reached. If not, a check is made on whether an serious adverse event (SAE) has occurred as this results in the patient dying, leaving the model or, more usually, receiving treatment for their SAE in hospital for four weeks before resuming their treatment. Patients who have not suffered an SAE are checked for sputum smear conversion. If they have converted, they continue treatment according to their allocated strategy upto week 16 when they move to the continuation phase (CP). If the patient has not converted by week 16 they will enter the Extended IP for an additional 8 weeks. If conversion occurs, they will then continue the CP for further 24 weeks. If conversion has not occurred by week 24 then the patient is transferred to a different treatment plan and excluded from the model