Treatment efficacy of drug-resistant tuberculosis in Bashkortostan, Russia: A retrospective cohort study

Abstract

Background: Russia, together with other former Soviet Union countries, is characterized by one of the highest burdens of drug-resistant tuberculosis. Published data on the drug-resistant tuberculosis for these countries are limited, and it is not clear whether current treatment regimens remain effective against constantly evolving drug-resistant strains. Objectives: The aim of the study was to evaluate treatment efficacy of patients with multidrug-resistant (MDR), extensively drug-resistant (XDR) and drug-susceptible (DSTB) tuberculosis in the most populous region of Russia (Bashkortostan) that borders with Central Asia. Methods: A retrospective cohort study was performed on 436 patients with pulmonary tuberculosis who were enrolled between January 1, 2016, and February 28, 2018, and received treatment according to WHO recommendations. Altogether, 369 patients completed the full course of chemotherapy. Clinical characteristics and treatment outcomes of DSTB, MDR, and XDR-TB patients were analyzed. Results: Of 436 patients, 169 (39%) had XDR-TB, 94 (22%) had MDR-TB and 173 (40%) had DSTB. Half of the MDR-TB patients (44%) and 82% of XDR-TB patients failed treatment. Patients with DSTB had unexpectedly poor treatment efficacy: only 67% had treatment success. We found that most of the MDR isolates from our patients were resistant to all first-line drugs, and a majority of the XDR isolates were resistant to more than 6-7 anti-TB drugs. While this can explain poor treatment efficacy in drug-resistant cases, causes of poor treatment efficacy in DSTB patients remain unclear. Finally, a considerable fraction (46%) of newly diagnosed patients had MDR-TB (27%) and XDR-TB (19%), suggesting that drug-resistant Mtb is being transmitted in the general population. To our best knowledge, this study is the first one to report XDR-TB prevalence in Russia in recent years (2016)(2017)(2018). Conclusions: MDR and XDR-TB became more common in recent years and treatment efficacy is declining at the face of more extensive drug resistance. There is evidence for the transmission of resistant strains in the general population, which calls for urgent changes not only in clinical practice but also in measures to prevent spread in the general population.

Treatment Outcomes of Extensively Drug-Resistant Tuberculosis in Pakistan: A Countrywide Retrospective Record Review

“…The mortality rate in our cohort was comparatively higher than the frequency of deaths observed among XDR-TB patients in Georgia (15.09%) (Frank et al, 2019), Estonia (17.54%) (Kliiman & Altraja, 2009) and Russia (23.61%) (Yunusbaeva et al, 2019), and lower than that observed in India (51.8%) (Prajapati et al, 2017) and South Africa (43 and 53%) (Pietersen et al, 2015;Yuengling et al, 2018). The relatively low mortality rate in the aforementioned studies could be due to the hiding of death by high LTUF rate ranging from 14.81 to 37.7% in these studies (Kliiman and Altraja, 2009;Frank et al, 2019;Yunusbaeva et al, 2019) as compared to 7.7% in our cohort. In the multivariate analysis, elderly patients (>60 years old) were significantly more likely to die.…”

“…In the present cohort, the treatment success rate (40.6%) was comparable with the global treatment success rate (39%) among XDR-TB patients (2016 cohort) (World Health Organization, 2018). However, it was better than the rates reported from Tajikistan (5.6%) (Makhmudova et al, 2019), Russia (12%) (Yunusbaeva et al, 2019), South Africa (4 and 31.4%) (Yuengling et al, 2018;Te Riele et al, 2019), China (14.6 and 30%) (Alene et al, 2017;He et al, 2017), India (25.9%) (Prajapati et al, 2017) and Georgia (33%) (Frank et al, 2019), and lower than the ones reported from Brazil (48.4%) (Gallo et al, 2018) and Argentina (65%) (Abbate et al, 2012).…”

“…To the best of our knowledge, this is the first study which evaluated the treatment outcomes and factors associated with unsuccessful outcomes among XDR-TB patients enrolled for treatment at 27 PMDT units all over Pakistan. As the previously published individual cohorts from different countries have included a relatively small number of XDR-TB patients ranging from 12 to 195 (Kwon et al, 2008;Kliiman & Altraja, 2009;Pietersen et al, 2015;Yuengling et al, 2018;Makhmudova et al, 2019;Yunusbaeva et al, 2019), the large sample size of 404 XDR-TB patients from all over the country is the major strength of this study. In the present cohort, the treatment success rate (40.6%) was comparable with the global treatment success rate (39%) among XDR-TB patients (2016 cohort) (World Health Organization, 2018).…”

Unfavorable outcomes to second-line tuberculosis therapy among HIV-infected versus HIV-uninfected patients in sub-Saharan Africa: A systematic review and meta-analysis

“…Prolonged therapy is required for the toxic second-line anti-tuberculosis treatment which is burdensome for patient compliance [ 13 ]. This prolonged treatment with the less tolerated second-line anti-tuberculosis treatment regimen might have a lower rate of patient compliance with the treatment that could affect the outcome of therapy [ 15 , 16 ]. As a result, a lower rate of unfavorable outcome during the DR-TB treatment is a key component that indicates a successful outcome for the epidemic [ 17 ].…”

Factors associated with mortality from tuberculosis in Iran: an application of a generalized estimating equation-based zero-inflated negative binomial model to national registry data

“…Other potential risk factors such as diabetes, HIV infection, malnourishment, and silicosis can increase the risk of developing TB. Various studies have explored this issue and reported valuable results, including confirmation of the effects of HIV infection [9,10], low body mass index (BMI) [11], diabetes [12], smoking [13], poverty and malnourishment [14], and alcohol use on TB. Several studies have also reported that the risk of TB mortality was closely related to the presence of diseases such as HIV, silicosis, and diabetes, as well as individual and social characteristics [15,16].…”