S P Althomsons1, J P Cegielski. 1. Division of Tuberculosis Elimination, US Centers for Disease Control and Prevention, Atlanta, GA, USA. SAlthomsons@cdc.gov
Abstract
SETTING: The worldwide emergence of extensively drug-resistant tuberculosis (TB) has focused attention on treatment with second-line drugs (SLDs). OBJECTIVE: To determine the impact on outcomes of resistance to individual SLDs, we analyzed successful treatment completion and death among drug-resistant TB cases in the US national TB surveillance system, 1993-2007 (N = 195 518). DESIGN: We defined four combinations of first-line drug (FLD) resistance based on isoniazid (INH) and rifamycin, and three patterns of SLD resistance: fluoroquinolones, injectable SLDs and other oral SLDs. We compared treatment outcomes of cases by FLD resistance, with and without each pattern of SLD resistance. RESULTS: In all but one instance, cases with FLD resistance but no SLD resistance had better outcomes than cases with SLD resistance. Rifamycin resistance, alone or with INH, resulted in a greater decline in treatment completion and greater increase in deaths than resistance to SLDs. Among patients with multidrug-resistant TB, additional resistance to injectable SLDs was statistically significant. Outcomes were better for human immunodeficiency virus (HIV) negative than HIV-positive cases for all resistance patterns, but improved among HIV-infected cases after 1998, when highly active antiretroviral treatment became widely available. CONCLUSION: These results suggest that the effect of rifamycin resistance may outweigh the more modest effects of resistance to specific SLDs.
SETTING: The worldwide emergence of extensively drug-resistant tuberculosis (TB) has focused attention on treatment with second-line drugs (SLDs). OBJECTIVE: To determine the impact on outcomes of resistance to individual SLDs, we analyzed successful treatment completion and death among drug-resistant TB cases in the US national TB surveillance system, 1993-2007 (N = 195 518). DESIGN: We defined four combinations of first-line drug (FLD) resistance based on isoniazid (INH) and rifamycin, and three patterns of SLD resistance: fluoroquinolones, injectable SLDs and other oral SLDs. We compared treatment outcomes of cases by FLD resistance, with and without each pattern of SLD resistance. RESULTS: In all but one instance, cases with FLD resistance but no SLD resistance had better outcomes than cases with SLD resistance. Rifamycin resistance, alone or with INH, resulted in a greater decline in treatment completion and greater increase in deaths than resistance to SLDs. Among patients with multidrug-resistant TB, additional resistance to injectable SLDs was statistically significant. Outcomes were better for human immunodeficiency virus (HIV) negative than HIV-positive cases for all resistance patterns, but improved among HIV-infected cases after 1998, when highly active antiretroviral treatment became widely available. CONCLUSION: These results suggest that the effect of rifamycin resistance may outweigh the more modest effects of resistance to specific SLDs.
Authors: Suzanne M Marks; Jennifer Flood; Barbara Seaworth; Yael Hirsch-Moverman; Lori Armstrong; Sundari Mase; Katya Salcedo; Peter Oh; Edward A Graviss; Paul W Colson; Lisa Armitige; Manuel Revuelta; Kathryn Sheeran Journal: Emerg Infect Dis Date: 2014-05 Impact factor: 6.883