Sputum Culture Conversion among Patients with Drug-Resistant Tuberculosis: A Study of Various Predictors

Abstract

Introduction: Conversion of a positive sputum culture to a negative culture is an important parameter in the management of drug-resistant tuberculosis (TB), as the failure to convert was related to dismal posttreatment outcomes and elevated mortality rates by almost eight times when compared to victims of multidrug-resistant TB (MDR-TB) who did so. In the patients of MDR-TB, it is an important sign of treatment success to have sputum culture converted from positive to negative, and helps in determining the duration of treatment. The goal of this study was to examine and compare the length of time it took to convert an initial sputum culture with predictors of treatment outcomes for patients with MDR-TB, as well as to pinpoint the variables that affected the length of time. Materials and Methods: The mixed method (records review and qualitative approach) was used to understand the patient’s perspective for accepting the Programmatic Management of Drug-resistant TB (PMDT) services and the provider’s perspective for rendering services in a public-private mix model setup. This study was undertaken as a retrospective analysis and studied the patients drug-resistant TB who were admitted to a tertiary care hospital in central India. This study was carried out on the patients of Rifampicin-Resistant TB (RR-TB) and MDR-TB (Resistant to both INH and Rifampicin) with positive baseline culture, pretreatment evaluation, and appropriate anti-MDR-TB treatment. As per the PMDT guidelines, sputum smear and culture reports were collected and analyzed. Results: In this study, the time and predictors to convert an initial positive sputum culture to negative and factors influencing treatment outcome were evaluated, compared, and identified. A total of 163 patients were evaluated and analyzed. Of these, 111 (68.09%) were rifampicin and INH-resistant (MDR-TB), whereas 52 (31.90%) were rifampicin resistant (RR-TB) only. Overall 68 (41.71%) patients with baseline positive culture were converted within 3 months. Conclusions: It was concluded that malnourishment, human immunodeficiency virus positivity, associated extra pulmonary TB, and bilateral cavitation were found to be significant predictors of longer time of sputum culture conversion and thereby treatment outcome.