Frequency and characteristics of TB relapses

Abstract

Introduction: Orel oblast, Russia, as a WHO pilot region implemented regional TB Control programme in 1999-2013. In 2002 -2014 the region provided treatment of 4532 non-MDR-TB patients and 633 MDR-TB patients. Treatment success rate for non MDR-TB cases comprised 88.1% and for MDR-TB cases - 60.8%. Objective: Identify frequency and to study timeline of manifestation and drug resistance of strains in TB relapses after successful treatment of non MDR-TB and MDR-TB patients Methods: Retrospective study of TB relapses manifestation after successful treatment in yearly cohorts of 3221 non MDR-TB patients and 385 MDR-TB patients. Results: There were registered 104 (2.6%) [СI 95% 2,65- 3,87] TB relapses after successful treatment of non MDR-TB and 15 (3.2%) [CI 95% 2,2 - 6,06] among MDR-TB patients. 49 (47.1%) non MDR-TB cases and 2 (13.3%) MDR TB cases were detected in first three years. 28 (26.9%) non MDR-TB patients and 6 (40%) MDR-TB were detected as relapses within 4-5 years of observation. 27 (26.0%) non MDR-TB patients and 7 (46.7%) MDR-TB patients had relapses after 5 years of observation. Additional drug resistance in relapses was found. DST results showed MDR-TB in 27 (26.0%) cases of relapse who had treatment of non MDR-TB and 4 (26,7%) XDR-TB cases were diagnosed in relapses after MDR-TB treatment. Conclusion: Frequency of TB relapses comprised 2,6% [2,65- 3,87] in non MDR-TB cohorts and [3.2% 2,2 - 6,06] in MDR-TB cohorts. 47.9% relapses in non MDR-TB cohorts were registered within first 3 years and 74.0% - in 5 years of observation. In MDR-TB cohorts 46.7% of relapses were detected after 5 years of observation. 26.0% relapses after treatment of non MDR-TB manifested MDR-TB and 26.7% after MDR-TB treatment – XDR-TB.