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Volume 22, Number 3—March 2016

Decreased Time to Treatment Initiation for Multidrug-Resistant Tuberculosis Patients after Use of Xpert MTB/RIF Test, Latvia

Helen R. StaggComments to Author , Peter A. White, Vija Riekstiņa, Andra Cīrule, Ģirts Šķenders, Vaira Leimane1, Liga Kuksa1, Gunta Dravniece, James Brown, and Charlotte Jackson
Author affiliations: University College London, London, UK (H.R. Stagg, J. Brown, C. Jackson); Medical Research Council Centre for Outbreak Analysis and Modelling, London (P.J. White); National Institute for Health Research Health Protection Research Unit in Modelling Methodology, London (P.J. White); Imperial College School of Public Health, London (P.J. White); Public Health England, London (P.J. White); University of Latvia, Riga, Latvia (V. Riekstiņa); Riga East University Hospital, Riga (V. Riekstiņa, A. Cīrule, Ģ. Šķenders, V. Leimane, L. Kuksa); KNCV Tuberculosis Foundation, The Hague, the Netherlands (G. Dravniece); Royal Free London National Health Service Trust, London (J. Brown)

Main Article

Table 4

Sensitivity analyses for findings of multivariable accelerated failure time model for association between Xpert MTB/RIF use and time to MDR TB treatment initiation for patients in MDR TB treatment cohorts, Latvia, 2009–2012*

Exposure: Xpert MTB/RIF Stratifier: previous TB Time ratio (95% CI), p value
Model 1: 2-Strata Xpert, year as confounder Model 2: 
3-Strata Xpert Model 3: 3-Strata Xpert, year as confounder
Not conducted No Baseline Baseline Baseline
Conducted, rifampin-resistant TB No 0.15 (0.11−0.21), <0.001 0.16 (0.12−0.21), <0.001 0.15 (0.11−0.20), <0.001
Conducted, negative result No NA 1.17 (0.62−2.22), 0.62 1.09 (0.57−2.09), 0.80
Not conducted Yes Baseline Baseline Baseline
Conducted, rifampin-resistant TB Yes 0.45 (0.27−0.77), 0.003 0.33 (0.20−0.54), <0.001 0.45 (0.27−0.76), 0.003
Conducted, negative result Yes NA 2.97 (1.07−8.28), 0.04 3.63 (1.27−10.37), 0.02

*Three models of sensitivity of the association between Xpert MTB/RIF use and the time to MDR TB treatment initiation stratified by the effect modifier previous TB were used. Model 1 included year as a confounder (restricting the dataset to 2010–2012; 258 patients). Model 2 included persons who had negative results for rifampin resistance by Xpert MTB/RIF (387 patients). Model 3: models 1 and 2 assessed simultaneously (273 patients). A final model was adjusted for all variables except country of birth, social risk factors, and HIV status (plus year where stated). Median in baseline strata of Xpert MTB/RIF and previous tuberculosis was 41 days for all analyses. A positive result was rifampin-resistant TB, and a negative result was rifampin sensitivity or no TB detected. MTB, Mycobacterium tuberculosis; RIF, rifampin. MDR TB, multidrug-resistant tuberculosis; NA, not applicable.

Main Article

1These authors contributed equally to this article.

Page created: March 01, 2016
Page updated: March 01, 2016
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