Time to sputum culture conversion as a prognostic marker for end-of-treatment outcome in the first cohorts of MDR-TB patients managed in a Nigerian tertiary hospital

Objective: The aim of this study was to assess the validity of sputum culture conversion at varying timepoints as prognostic markers for end-of-treatment outcome in patients with MDR TB. Methods: A retrospective study was conducted for the period 2010-2013, at the MDR-TB treatment center of the University College Hospital Ibadan, Nigeria. GeneXpert was done for confirmation of rifampicin resistance and MDR-TB was confirmed by sputum culture and DST. Sputum culture was done at baseline and monthly during the intensive phase and also every 2 months at follow up visits. Results: The Cohorts of 115 patients that had completed the therapy for multidrug-resistant TB were studied. 39(33.9%) were males and 76(66.1%) females. Their ages ranged between 15 and 65 years. The mean age was 32.44 ± 12.63 years. The median time of conversion in months was 1.91 ± 1.20. 91(97.5%) and 112(97.4%) were sputum culture converted at the end 2 nd and 5 th month respectively. Overall 69.0% (79/115) of patients had treatment success as shown by the cure rate of 41% (47/115) and treatment completed rate of 28% (32/115). Treatment failure occurred in only 1 patient. The default rate was 6% (7/115) and a total of 28 (24%) deaths were recorded. Patients who converted sputum culture at 2 months had a higher chance of treatment success than those with no conversion at 2 months. Conclusion: The study has shown that most patients with MDR-TB achieved sputum culture conversion within 2 months of starting treatment. Treatment outcome relates more to sputum conversion at the 2 nd and 5 th months. There was no significant interaction with HIV status.