Aggressive regimens for multidrug-resistant tuberculosis decrease all-cause mortality

The Association Between Sputum Culture Conversion and Mortality in Cavitary Mycobacterium avium Complex Pulmonary Disease

BACKGROUND

The association between treatment outcome and the mortality of patients with Mycobacterium avium complex pulmonary disease (MAC-PD) with cavitary lesions is unclear. This article assessed the impact of culture conversion on mortality in patients with cavitary MAC-PD.

RESEARCH QUESTION

Is the achievement of sputum culture conversion in patients with MAC-PD with cavitary lesions associated with the prognosis?

STUDY DESIGN AND METHODS

From 2002 to 2020, a total of 351 patients with cavitary MAC-PD (105 with the fibrocavitary type and 246 with the cavitary nodular bronchiectatic type), who had been treated with a ≥ 6-month macrolide-containing regimen at a tertiary referral center in South Korea, were retrospectively enrolled in this study. All-cause mortality during the follow-up period was analyzed based on culture conversion at the time of treatment completion.

RESULTS

The cohort had a median treatment duration of 14.7 months (interquartile range [IQR], 13.4-16.8 months). Of the 351 patients, 69.8% (245 of 351) achieved culture conversion, and 30.2% (106 of 351) did not. The median follow-up was 4.4 years (IQR, 2.3-8.3 years) in patients with culture conversion and 3.1 years (IQR, 2.1-4.8 years) in those without. For the patients with and without culture conversion, all-cause mortality was 5.3% vs 35.8% (P < .001), and the 5-year cumulative mortality was 20.0% vs 38.4%, respectively. Cox analysis found that a lack of culture conversion was significantly associated with higher mortality (adjusted hazard ratio, 5.73; 95% CI, 2.86-11.50). Moreover, the 2-year landmark analysis revealed a distinct impact of treatment outcome on mortality.

INTERPRETATION

The mortality rate of patients with cavitary MAC-PD who did not achieve culture conversion was significantly higher than that of those with culture conversion.

Survival Probability in Multidrug Resistant Pulmonary Tuberculosis Patients in a South Indian Region

Background: Drug-resistant tuberculosis is a burgeoning threat to public health requiring novel strategies to combat the infection. Although national tuberculosis elimination programs focus on improving health services, challenges in eradicating tuberculosis still exist. Factors attributing to unfavorable outcomes are unknown in Warangal district of Telangana state. Methods: This study included 296 patients diagnosed with multidrug-resistant pulmonary tuberculosis. The study participants followed up for a maximum of 20 months to determine treatment outcomes. Statistical applications of Kaplan-Meier curve and log-rank test used to find the survival probabilities in subgroups. Results: The survival of multidrug-resistant pulmonary tuberculosis patients was ascertained, in male and female patients, aged between 31 and 50 years. Resistance to rifampicin was prominent. The study found a survival rate of 76.68% and a mortality rate of 23.31%. The log-rank test revealed a significant difference in survival in subcategories with and without comorbidities (P = .03), non-adherence to treatment (P = .0001), treatment duration (P = .02), regimens (P = .01), and grading of radiograph (P = .0001). Conclusion: This study identified factors that influenced the survival probability of multidrug-resistant pulmonary tuberculosis patients, including comorbidities, weight band, non-adherence to treatment, treatment duration, regimens, and grading of radiograph. These findings emphasize the need for enhanced management strategies to improve treatment outcomes.

Genetic Characterization and Population Structure of Drug-Resistant Mycobacterium tuberculosis Isolated from Brazilian Patients Using Whole-Genome Sequencing

The present study aimed to determine the genetic diversity of isolates of Mycobacterium tuberculosis (Mtb) from presumed drug-resistant tuberculosis patients from several states of Brazil. The isolates had been submitted to conventional drug susceptibility testing for first- and second-line drugs. Multidrug-resistant (MDR-TB) (54.8%) was the most frequent phenotypic resistance profile, in addition to an important high frequency of pre-extensive resistance (p-XDR-TB) (9.2%). Using whole-genome sequencing (WGS), we characterized 298 Mtb isolates from Brazil. Besides the analysis of genotype distribution and possible correlations between molecular and clinical data, we determined the performance of an in-house WGS pipeline with other online pipelines for Mtb lineages and drug resistance profile definitions. Sub-lineage 4.3 (52%) was the most frequent genotype, and the genomic approach revealed a p-XDR-TB level of 22.5%. We detected twenty novel mutations in three resistance genes, and six of these were observed in eight phenotypically resistant isolates. A cluster analysis of 170 isolates showed that 43.5% of the TB patients belonged to 24 genomic clusters, suggesting considerable ongoing transmission of DR-TB, including two interstate transmissions. The in-house WGS pipeline showed the best overall performance in drug resistance prediction, presenting the best accuracy values for five of the nine drugs tested. Significant associations were observed between suffering from fatal disease and genotypic p-XDR-TB (p = 0.03) and either phenotypic (p = 0.006) or genotypic (p = 0.0007) ethambutol resistance. The use of WGS analysis improved our understanding of the population structure of MTBC in Brazil and the genetic and clinical data correlations and demonstrated its utility for surveillance efforts regarding the spread of DR-TB, hopefully helping to avoid the emergence of even more resistant strains and to reduce TB incidence and mortality rates.

Unsuccessful treatment outcome and associated risk factors. A prospective study of DR-TB patients from a high burden country, Pakistan

INTRODUCTION

Tuberculosis (TB), a curable and preventable infectious disease, becomes difficult to treat if resistance against most effective and tolerable first line anti-TB drugs is developed. The objective of the present study was to evaluate the treatment outcomes and predictors of poor outcomes among drug-resistant tuberculosis (DR-TB) patients treated at a programmatic management unit of drug resistant tuberculosis (PMDT) unit, Punjab, Pakistan.

METHODS

This prospective observational study was conducted at a a PMDT unit in Multan, Punjab, Pakistan. A total of 271 eligible culture positive DR-TB patients enrolled for treatment at the study site between January 2016 and May 2017 were followed till their treatment outcomes were recorded. World Health Organization's (WHO) defined criteria was used for categorizing treatment outcomes. The outcomes of cured and treatment completed were collectively placed as successful outcomes, while death, lost to follow-up (LTFU) and treatment failure were grouped as unsuccessful outcomes. Multivariable binary logistic regression analysis was employed for getting predictors of unsuccessful treatment outcomes. A p-value <0.05 was considered statistically significant.

RESULTS

Of the 271 DR-TB patients analysed, nearly half (51.3%) were males. The patient's (Mean ± SD) age was 36.75 ± 15.69 years. A total of 69% patients achieved successful outcomes with 185 (68.2%) patients being cured and 2 (0.7%) completed therapy. Of the remaining 84 patients with unsuccessful outcomes, 48 (17.7%) died, 2 (0.7%) were declared treatment failure, 34 (12.5%) were loss to follow up. After adjusting for confounders, patients' age > 50 years (OR 2.149 (1.005-4.592) with p-value 0.048 and baseline lung cavitation (OR 7.798 (3.82-15.919) with p-value <0.001 were significantly associated with unsuccessful treatment outcomes.

CONCLUSIONS

The treatment success rate (69%) in the current study participants was below the target set by WHO (>75%). Paying special attention and timely intervention in patients with high risk of unsuccessful treatment outcomes may help in improving treatment outcomes at the study site.

Characterizing the gene mutations associated with resistance to gatifloxacin in Mycobacterium tuberculosis through whole-genome sequencing

OBJECTIVES

Gatifloxacin (GAT), a fourth-generation fluoroquinolone (FQ), is used to treat drug-resistant tuberculosis. Although DNA gyrase mutations are the leading cause of FQ resistance, mutations conferring resistance to GAT remain inadequately characterized.

METHODS

GAT-resistant mutants were selected from 7H10 agar plates containing 0.5 mg/L GAT (critical concentration). Mutations involved in GAT resistance were identified through whole-genome sequencing.

RESULTS

In total, 123 isolates demonstrated resistance to GAT. Among these isolates, 55.3% (68/123) had gyrA gene mutations [G280A (D94N), A281G (D94G), G280T (D94Y) and G262T (G88C)]. The remainder (44.7%, 55/123) harboured gyrB gene mutations [A1495G (N499D), C1497A (N499K), C1497G (N499K) and A1503C (E501D)].

CONCLUSIONS

Mutations in the gyrA and gyrB genes are the main mechanisms of GAT resistance. These findings provide new insight into GAT resistance, and contribute to molecular diagnosis of GAT resistance in the clinical setting.

Predictors of mortality in patients with drug-resistant tuberculosis: A systematic review and meta-analysis

BACKGROUND

Even though the lives of millions have been saved in the past decades, the mortality rate in patients with drug-resistant tuberculosis is still high. Different factors are associated with this mortality. However, there is no comprehensive global report addressing these risk factors. This study aimed to determine the predictors of mortality using data generated at the global level.

METHODS

We systematically searched five electronic major databases (PubMed/Medline, CINAHL, EMBASE, Scopus, Web of Science), and other sources (Google Scholar, Google). We used the Joanna Briggs Institute Critical Appraisal tools to assess the quality of included articles. Heterogeneity assessment was conducted using the forest plot and I2 heterogeneity test. Data were analyzed using STATA Version 15. The pooled hazard ratio, risk ratio, and odd's ratio were estimated along with their 95% CIs.

RESULT

After reviewing 640 articles, 49 studies met the inclusion criteria and were included in the final analysis. The predictors of mortality were; being male (HR = 1.25,95%CI;1.08,1.41,I2;30.5%), older age (HR = 2.13, 95%CI;1.64,2.62,I2;59.0%,RR = 1.40,95%CI; 1.26, 1.53, I2; 48.4%) including a 1 year increase in age (HR = 1.01, 95%CI;1.00,1.03,I2;73.0%), undernutrition (HR = 1.62,95%CI;1.28,1.97,I2;87.2%, RR = 3.13, 95% CI; 2.17,4.09, I2;0.0%), presence of any type of co-morbidity (HR = 1.92,95%CI;1.50-2.33,I2;61.4%, RR = 1.61, 95%CI;1.29, 1.93,I2;0.0%), having diabetes (HR = 1.74, 95%CI; 1.24,2.24, I2;37.3%, RR = 1.60, 95%CI;1.13,2.07, I2;0.0%), HIV co-infection (HR = 2.15, 95%CI;1.69,2.61, I2; 48.2%, RR = 1.49, 95%CI;1.27,1.72, I2;19.5%), TB history (HR = 1.30,95%CI;1.06,1.54, I2;64.6%), previous second-line anti-TB treatment (HR = 2.52, 95% CI;2.15,2.88, I2;0.0%), being smear positive at the baseline (HR = 1.45, 95%CI;1.14,1.76, I2;49.2%, RR = 1.58,95%CI;1.46,1.69, I2;48.7%), having XDR-TB (HR = 2.01, 95%CI;1.50,2.52, I2;60.8%, RR = 2.44, 95%CI;2.16,2.73,I2;46.1%), and any type of clinical complication (HR = 2.98, 95%CI; 2.32, 3.64, I2; 69.9%). There are differences and overlaps of predictors of mortality across different drug-resistance categories. The common predictors of mortality among different drug-resistance categories include; older age, presence of any type of co-morbidity, and undernutrition.

CONCLUSION

Different patient-related demographic (male sex, older age), and clinical factors (undernutrition, HIV co-infection, co-morbidity, diabetes, clinical complications, TB history, previous second-line anti-TB treatment, smear-positive TB, and XDR-TB) were the predictors of mortality in patients with drug-resistant tuberculosis. The findings would be an important input to the global community to take important measures.

Treatment outcomes of drug resistant tuberculosis patients with multiple poor prognostic indicators in Uganda: A countrywide 5-year retrospective study

BACKGROUND

Comorbid conditions and adverse drug events are associated with poor treatment outcomes among patients with drug resistant tuberculosis (DR - TB). This study aimed at determining the treatment outcomes of DR - TB patients with poor prognostic indicators in Uganda.

METHODS

We reviewed treatment records of DR - TB patients from 16 treatment sites in Uganda. Eligible patients had confirmed DR - TB, a treatment outcome in 2014-2019 and at least one of 15 pre-defined poor prognostic indicators at treatment initiation or during therapy. The pre-defined poor prognostic indicators were HIV co-infection, diabetes, heart failure, malignancy, psychiatric illness/symptoms, severe anaemia, alcohol use, cigarette smoking, low body mass index, elevated creatinine, hepatic dysfunction, hearing loss, resistance to fluoroquinolones and/or second-line aminoglycosides, previous exposure to second-line drugs (SLDs), and pregnancy. Tuberculosis treatment outcomes were treatment success, mortality, loss to follow up, and treatment failure as defined by the World Health Organisation. We used logistic and cox proportional hazards regression analysis to determine predictors of treatment success and mortality, respectively.

RESULTS

Of 1122 DR - TB patients, 709 (63.2%) were male and the median (interquartile range, IQR) age was 36.0 (28.0-45.0) years. A total of 925 (82.4%) had ≥2 poor prognostic indicators. Treatment success and mortality occurred among 806 (71.8%) and 207 (18.4%) patients whereas treatment loss-to-follow-up and failure were observed among 96 (8.6%) and 13 (1.2%) patients, respectively. Mild (OR: 0.57, 95% CI 0.39-0.84, p = 0.004), moderate (OR: 0.18, 95% CI 0.12-0.26, p < 0.001) and severe anaemia (OR: 0.09, 95% CI 0.05-0.17, p < 0.001) and previous exposure to SLDs (OR: 0.19, 95% CI 0.08-0.48, p < 0.001) predicted lower odds of treatment success while the number of poor prognostic indicators (HR: 1.62, 95% CI 1.30-2.01, p < 0.001), for every additional poor prognostic indicator) predicted mortality.

CONCLUSION

Among DR - TB patients with multiple poor prognostic indicators, mortality was the most frequent unsuccessful outcomes. Every additional poor prognostic indicator increased the risk of mortality while anaemia and previous exposure to SLDs were associated with lower odds of treatment success. The management of anaemia among DR - TB patients needs to be evaluated by prospective studies. DR - TB programs should also optimise DR - TB treatment the first time it is initiated.

Comparison of censoring assumptions to reduce bias in tuberculosis treatment cohort analyses

Objective

Observational tuberculosis cohort studies are often limited by a lack of long-term data characterizing survival beyond the initial treatment outcome. Though Cox proportional hazards models are often applied to these data, differential risk of long-term survival, dependent on the initial treatment outcome, can lead to violations of model assumptions. We evaluate the performance of two alternate censoring approaches on reducing bias in treatment effect estimates.

Design

We simulate a typical multidrug-resistant tuberculosis cohort study and use Cox proportional hazards models to assess the relationship of an aggressive treatment regimen with hazard of death. We compare three assumptions regarding censored observations to determine which produces least biased treatment effect estimates: conventional non-informative censoring, an extension of short-term survival informed by literature, and incorporation of predicted long-term vital status.

Results

The treatment regimen’s protective effect on death is consistently underestimated by the conventional censoring method, up to 7.6%. Models using the two alternative censoring techniques produce treatment effect estimates consistently stronger and less biased than the conventional method, underestimating the treatment effect by less than 2.4% across all scenarios.

Conclusions

When model assumptions are violated, alternative censoring techniques can more accurately estimate associations between treatment and long-term survival. In multidrug-resistant tuberculosis cohort analyses, this bias reduction may yield more accurate and, larger effect estimates. This bias reduction can be achieved through use of standard statistical procedures with a simple re-coding of the censoring indicator.

Poor treatment outcome and its predictors among drug-resistant tuberculosis patients in Ethiopia: A systematic review and meta-analysis

OBJECTIVE

To assess poor treatment outcomes and their predictors among drug-resistant tuberculosis patients treated in Ethiopia.

METHODS

Data were searched from both electronic databases and other sources. From the whole search, 404 articles were reviewed and 17 articles that fulfilled the inclusion criteria were included in the analysis. Preferred Reporting Items for Systematic Reviews and Meta-Analyses checklist was followed and Joanna Briggs Institute Critical Appraisal checklist was used for assessing the quality. Risk of bias was assessed using forest plot and Egger's regression test. Data were analyzed using STATA version 15 and Review Manager Software version 5.3.

RESULTS

The overall pooled proportion of poor treatment outcome and mortality was 17.86% and 15.13% respectively. The incidence density rate of poor treatment outcome and mortality was 10.41/1000 person-months and 9.28/1000 person-months respectively. Survival status and successful treatment outcomes were 76.97% and 63.82% respectively. HIV positivity, non-HIV comorbidities, clinical complications, extrapulmonary involvement, undernutrition, anemia, treatment delay, lower body weight, and older age were the predictors of poor treatment outcome.

CONCLUSION

Better survival and treatment success rates were noted in Ethiopia as compared to the global average. The majority of the poor treatment outcomes occurred within the intensive phase. Early initiation of anti-tuberculosis treatment would be important for successful treatment outcomes.

Applications of Molecular Simulation in the Discovery of Antituberculosis Drugs: A Review

After decades of efforts, tuberculosis has been well controlled in most places. The existing drugs are no longer sufficient for the treatment of drug-resistant Mycobacterium tuberculosis due to significant toxicity and selective pressure, especially for XDR-TB. In order to accelerate the development of high-efficiency, low-toxic antituberculosis drugs, it is particularly important to use Computer Aided Drug Design (CADD) for rational drug design. Here, we systematically reviewed the specific role of molecular simulation in the discovery of new antituberculosis drugs. The purpose of this review is to overview current applications of molecular simulation methods in the discovery of antituberculosis drugs. Furthermore, the unique advantages of molecular simulation was discussed in revealing the mechanism of drug resistance. The comprehensive use of different molecular simulation methods will help reveal the mechanism of drug resistance and improve the efficiency of rational drug design. With the help of molecular simulation methods such as QM/MM method, the mechanisms of biochemical reactions catalyzed by enzymes at atomic level in Mycobacterium tuberculosis has been deeply analyzed. QSAR and virtual screening both accelerate the development of highefficiency, low-toxic potential antituberculosis drugs. Improving the accuracy of existing algorithms and developing more efficient new methods for CADD will always be a hot topic in the future. It is of great value to utilize molecular dynamics simulation to investigate complex systems that cannot be studied in experiments, especially for drug resistance of Mycobacterium tuberculosis.

Type I interferon-driven susceptibility to Mycobacterium tuberculosis is mediated by IL-1Ra

The bacterium Mycobacterium tuberculosis (Mtb) causes tuberculosis (TB) and is responsible for more human mortality than any other single pathogen¹. Progression to active disease occurs in only a fraction of infected individuals and is predicted by an elevated type I interferon (IFN) response^2-7. Whether or how IFNs mediate susceptibility to Mtb has been difficult to study due to a lack of suitable mouse models^6-11. Here we examined B6.Sst1^S congenic mice that carry the “sensitive” allele of the Sst1 locus that confers susceptibility to Mtb^12-14. We found that enhanced production of type I IFNs was responsible for the susceptibility of B6.Sst1^S mice to Mtb. Type I IFNs affect the expression of hundreds of genes, several of which have previously been implicated in susceptibility to bacterial infections^6,7,15-18. Nevertheless, we found that heterozygous deficiency in just a single IFN target gene, Il1rn, which encodes IL-1 receptor antagonist (IL-1Ra), is sufficient to reverse IFN-driven susceptibility to Mtb in B6.Sst1^S mice. In addition, antibody-mediated neutralization of IL-1Ra provided therapeutic benefit to Mtb-infected B6.Sst1^S mice. Our results illustrate the value of the B6.Sst1^S mouse to model interferon-driven susceptibility to Mtb, and demonstrate that IL-1Ra is an important mediator of type I IFN-driven susceptibility to Mtb infections in vivo.

Improving outcomes for multi-drug-resistant tuberculosis in the Peruvian Amazon - a qualitative study exploring the experiences and perceptions of patients and healthcare professionals

BACKGROUND

Management for multi-drug-resistant tuberculosis (MDR-TB) is challenging and has poor patient outcomes. Peru has a high burden of MDR-TB. The Loreto region in the Peruvian Amazon is worst affected for reasons including high rates of poverty and poor healthcare access. Current evidence identifies factors that influence MDR-TB medication adherence, but there is limited understanding of the patient and healthcare professional (HCP) perspective, the HCP-patient relationship and other factors that influence outcomes. A qualitative investigation was conducted to explore and compare the experiences and perceptions of MDR-TB patients and their dedicated HCPs to inform future management strategies.

METHOD

Twenty-six, semi-structured in-depth interviews were conducted with 15 MDR-TB patients and 11 HCPs who were purposively recruited from 4 of the worst affected districts of Iquitos (capital of the Loreto region). Field notes and transcripts of the two groups were analysed separately using thematic content analysis. Ethics approval was received from the Institutional Research Ethics Committee, Department of Health, Loreto, and the University of Birmingham Internal Research Ethics Committee.

RESULTS

Four key themes influencing patient outcomes emerged in each participant group: personal patient factors, external factors, clinical factors, and the HCP-patient relationship. Personal factors included high standard patient and population knowledge and education, which can facilitate engagement with treatment by encouraging belief in evidence-based medicine, dispelling belief in natural medicines, health myths and stigma. External factors included the adverse effect of the financial impact of MDR-TB on patients and their families. An open, trusting and strong HCP-patient relationship emerged as a vitally important clinical factor influencing of patient outcomes. The results also provide valuable insight into the dynamic of the relationship and ways in which a good relationship can be fostered.

CONCLUSIONS

This study highlights the importance of financial support for patients, effective MDR-TB education and the role of the HCP-patient relationship. These findings add to the existing evidence base and provide insight into care improvements and policy changes that could improve outcomes if prioritised by local and national government.

Factors affecting outcomes of individualised treatment for drug resistant tuberculosis in an endemic region

BACKGROUND

Individualised treatment regimens for drug resistant tuberculosis have improved outcomes. This retrospective observational study examined potential factors that affect individualised treatment in an endemic region, and highlighted predictors of a successful outcome.

METHODS

We examined records of proven MDR, pre-XDR and XDR TB patients diagnosed and started on treatment between 2010 and 2014, and collected the following data for each patient: age, gender, comorbidities, past history of TB, diagnosis, site of disease, drug susceptibility testing (DST) results, treatment, adverse reactions to anti-tubercular drugs, treatment changes and outcomes, which were recorded as positive, negative or neutral. Tests of association were carried out between factors and outcomes, following which multiple logistic regression analysis was done to determine the predictors of a positive outcome such as patient cured after completion of treatment at 18 months or longer.

RESULTS

Fifty-nine patients completed treatment at our centre. The median age was 26 years (range 8-65 years). There were 31 (52.5%) female patients. Forty-four (74.6%) were successfully treated over a median treatment period of 23 months (range 18-30 months). Successful outcomes were associated with age less than 45 years (P=0.01, OR=6.67, 95% CI=1.73-23.47), resistance to fewer than five drugs (P=0.001, OR=9.51, 95% CI=2.50-38.18) and susceptibility to Group 4 drugs (P=0.04, OR=4.71, 95% CI=1.03-16.83).

CONCLUSIONS

Age and drug susceptibility were important predictors of treatment outcome.

Use of predicted vital status to improve survival analysis of multidrug-resistant tuberculosis cohorts

BACKGROUND

Multidrug-resistant tuberculosis (MDR-TB) cohorts often lack long-term survival data, and are summarized instead by initial treatment outcomes. When using Cox proportional hazards models to analyze these cohorts, this leads to censoring subjects at the time of the initial treatment outcome, instead of them providing full survival data. This may violate the non-informative censoring assumption of the model and may produce biased effect estimates. To address this problem, we develop a tool to predict vital status at the end of a cohort period using the initial treatment outcome and assess its ability to reduce bias in treatment effect estimates.

METHODS

We derive and apply a logistic regression model to predict vital status at the end of the cohort period and modify the unobserved survival outcomes to better match the predicted survival experience of study subjects. We compare hazard ratio estimates for effect of an aggressive treatment regimen from Cox proportional hazards models using time to initial treatment outcome, predicted vital status, and true vital status at the end of the cohort period.

RESULTS

Models fit from initial treatment outcomes underestimate treatment effects by up to 22.1%, while using predicted vital status reduced this bias by 5.4%. Models utilizing the predicted vital status produce effect estimates consistently stronger and closer to the true treatment effect than estimates produced by models using the initial treatment outcome.

CONCLUSIONS

Although studies often use initial treatment outcomes to estimate treatment effects, this may violate the non-informative censoring assumption of the Cox proportional hazards model and result in biased treatment effect estimates. Using predicted vital status at the end of the cohort period may reduce this bias in the analyses of MDR-TB treatment cohorts, yielding more accurate, and likely larger, treatment effect estimates. Further, these larger effect sizes can have downstream impacts on future study design by increasing power and reducing sample size needs.

Predictors of mortality in multidrug-resistant tuberculosis patients from Brazilian reference centers, 2005 to 2012

Objectives

To determine the main predictors of death in multidrug-resistant (MDRTB) patients from Brazil.

Design

Retrospective cohort study, a survival analysis of patients treated between 2005 and 2012.

Results

Of 3802 individuals included in study, 64.7% were men, mean age was 39 (1–93) years, and 70.3% had bilateral pulmonary disease. Prevalence of human immunodeficiency virus (HIV) was 8.3%. There were 479 (12.6%) deaths. Median survival time was 1452 days (4 years). Factors associated with increased risk of death were age greater than or equal to 60 years (hazard rate [HR] = 1.6, confidence interval [CI] = 1.15–2.2), HIV co-infection (HR = 1.46; CI = 1.05–1.96), XDR resistance pattern (HR = 1.74, CI = 1.05–2.9), beginning of treatment after failure (HR = 1.72, CI = 1.27–2.32), drug abuse (HR = 1.64, CI = 1.22–2.2), resistance to ethambutol (HR = 1.30, CI = 1.06–1.6) or streptomycin (HR = 1.24, CI = 1.01–1.51). Mainly protective factors were presence of only pulmonary disease (HR = 0.57, CI = 0.35–0.92), moxifloxacin use (HR = 0.44, CI = 0.25–0.80), and levofloxacin use (HR = 0.75; CI = 0.60–0.94).

Conclusion

A more comprehensive approach is needed to manage MDRTB, addressing early diagnostic, improving adhesion, and comorbidities, mainly HIV infection and drug abuse. The latest generation quinolones have an important effect in improving survival in MDRTB.

Pulmonary resection for patients with multidrug-resistant tuberculosis based on survival outcomes: a systematic review and meta-analysis

We investigated the survival benefit of pulmonary resection for patients with multidrug-resistant tuberculosis. To weigh the survival benefit of pulmonary resection for patients with multidrug-resistant tuberculosis who have undergone surgical treatment combined with medical chemotherapy compared with medical chemotherapy alone, we did a meta-analysis of available studies containing a hazard ratio for pulmonary resection. Among 1726 articles, 6 clinical reports, with a mean sample size of 47 patients per report, met the inclusion criteria. The pooled hazard ratio of 0.68 with a 95% confidence interval of approximately 0.44-1.07 suggested that the survival benefit of surgical pulmonary resection combined with chemotherapy, in a comparison of the groups 'with surgery' and 'without surgery', is not significantly greater than that of chemotherapy alone. Selection bias, due to the absence of rigid predetermined indications for pulmonary resection, limited the validity of this analysis. Due to the heterogeneity of the patient groups, greater attention is required to compute additional hazard ratios in future studies with stratification of factors such as cardiopulmonary functions, disease extent and the presence of a cavity. These additional computations in future studies are necessary to determine the survival benefit and to support the rigid surgical indications.

Fluoroquinolone Resistance Mutation Detection Is Equivalent to Culture-Based Drug Sensitivity Testing for Predicting Multidrug-Resistant Tuberculosis Treatment Outcome: A Retrospective Cohort Study

Background

Molecular diagnostics that rapidly and accurately predict fluoroquinolone (FQ) resistance promise to improve treatment outcomes for individuals with multidrug-resistant (MDR) tuberculosis (TB). Mutations in the gyr genes, though, can cause variable levels of in vitro FQ resistance, and some in vitro resistance remains unexplained by gyr mutations alone, but the implications of these discrepancies for treatment outcome are unknown.

Methods

We performed a retrospective cohort study of 172 subjects with MDR/extensively drug-resistant TB subjects and sequenced the full gyrA and gyrB open reading frames in their respective sputum TB isolates. The gyr mutations were classified into 2 categories: a set of mutations that encode high-level FQ resistance and a second set that encodes intermediate resistance levels. We constructed a Cox proportional model to assess the effect of the gyr mutation type on the time to death or treatment failure and compared this with in vitro FQ resistance, controlling for host and treatment factors.

Results

Controlling for other host and treatment factors and compared with patients with isolates without gyr resistance mutations, "high-level" gyr mutations significantly predict poor treatment outcomes with a hazard ratio of 2.6 (1.2-5.6). We observed a hazard of death and treatment failure with "intermediate-level" gyr mutations of 1.3 (0.6-3.1), which did not reach statistical significance. The gyr mutations were not different than culture-based FQ drug susceptibility testing in predicting the hazard of death or treatment failure and may be superior.

Conclusions

FQ molecular-based diagnostic tests may better predict treatment response than traditional drug susceptibility testing and open avenues for personalizing TB therapy.

Comorbidities and treatment outcomes in multidrug resistant tuberculosis: a systematic review and meta-analysis

Little is known about the impact of comorbidities on multidrug resistant (MDR) and extensively drug resistant (XDR) tuberculosis (TB) treatment outcomes. We aimed to examine the effect of human immunodeficiency virus (HIV), diabetes, chronic kidney disease (CKD), alcohol misuse, and smoking on MDR/XDRTB treatment outcomes. We searched MEDLINE, EMBASE, Cochrane Central Registrar and Cochrane Database of Systematic Reviews as per PRISMA guidelines. Eligible studies were identified and treatment outcome data were extracted. We performed a meta-analysis to generate a pooled relative risk (RR) for unsuccessful outcome in MDR/XDRTB treatment by co-morbidity. From 2457 studies identified, 48 reported on 18,257 participants, which were included in the final analysis. Median study population was 235 (range 60-1768). Pooled RR of unsuccessful outcome was higher in people living with HIV (RR = 1.41 [95%CI: 1.15-1.73]) and in people with alcohol misuse (RR = 1.45 [95%CI: 1.21-1.74]). Outcomes were similar in people with diabetes or in people that smoked. Data was insufficient to examine outcomes in exclusive XDRTB or CKD cohorts. In this systematic review and meta-analysis, alcohol misuse and HIV were associated with higher pooled OR of an unsuccessful outcome in MDR/XDRTB treatment. Further research is required to understand the role of comorbidities in driving unsuccessful treatment outcomes.

Prevalence and risk factors of multi-drug resistant tuberculosis in Dalian, China

Objectives To investigate the prevalence and risk factors associated with multi-drug resistant tuberculosis (MDR-TB) in Dalian, China. Methods This was a retrospective review of data from patients attending a TB clinic in Dalian, China between 2012 and 2015. Demographic and drug susceptibility data were retrieved from TB treatment cards. Univariate logistic analysis was used to assess the association between risk factors and MDR-TB. Results Among the 3552 patients who were smear positive for Mycobacterium tuberculosis (MTB), 2918 (82.2%) had positive MTB cultures and 1106 (31.1%) had isolates that showed resistance to at least one drug. The overall prevalence of MDR-TB was 10.1% (359/3552; 131/2261 [5.8%] newly diagnosed and 228/1291 [17.7%] previously treated patients). Importantly, 75 extensively drug-resistant TB isolates were detected from 25 newly treated and 50 previously treated patients. In total, 215 (6.1%) patients were infected with a poly-resistant strain of MTB. Previously treated patients and older patients were more likely to develop MDR-TB. Conclusions The study showed a high prevalence of MDR-TB among the study population. History of previous TB treatment and older age were associated with MDR-TB.

Predictors of poor treatment outcomes in multidrug-resistant tuberculosis patients: a retrospective cohort study

OBJECTIVES

We aimed to determine the characteristics, treatment outcomes and risk factors for poor treatment outcomes among multidrug-resistant (MDR) tuberculosis (TB) patients in Khyber Pakhtunkhwa province, Pakistan.

METHODS

A retrospective cohort study including all patients with MDR-TB who sought care at the MDR-TB unit in Peshawar was conducted between January 2012 and April 2014. Patients were followed until an outcome of TB treatment was recorded as successful (cured or completed) or unsuccessful. Binary logistic regression was used to identify predictors of poor outcome, i.e. unsuccessful treatment outcomes.

RESULTS

Overall, 535 patients were included. The proportion of female subjects was relatively higher (n = 300, 56.1%) than male subjects. The mean (standard deviation) age of patients was 30.37 (14.09) years. Of 535 patients for whom treatment outcomes were available, 402 (75.1%) were cured, 4 (0.7%) completed therapy, 34 (6.4%) had disease that failed to respond to therapy, 93 (17.4%) died and two (0.4%) defaulted; in total, 129 (24.1%) had an unsuccessful outcome. We found three significant predictors of unsuccessful treatment during multivariate logistic regression: being married (odds ratio (OR) = 2.17, 95% confidence interval (CI) 1.01, 4.66), resistance to second-line drugs (OR = 2.61, 95% CI 1.61, 4.21) and presence of extensively drug-resistant TB (OR = 7.82, 95% CI 2.90, 21.07).

CONCLUSIONS

Approximately 75% of the treatment success rate set by the Global Plan to Stop TB was achieved. Resistance to second-line drugs and presence of extensively drug-resistant TB are the main risk factors for poor treatment outcomes.

WHO Treatment Guidelines for Drug-Resistant Tuberculosis, 2016 Update: Applicability in South Korea

Despite progress made in tuberculosis control worldwide, the disease burden and treatment outcome of multidrug-resistant tuberculosis (MDR-TB) patients have remained virtually unchanged. In 2016, the World Health Organization released new guidelines for the management of MDR-TB. The guidelines are intended to improve detection rate and treatment outcome for MDR-TB through novel, rapid molecular testing and shorter treatment regimens. Key changes include the introduction of a new, shorter MDR-TB treatment regimen, a new classification of medicines and updated recommendations for the conventional MDR-TB regimen. This paper will review these key changes and discuss the potential issues with regard to the implementation of these guidelines in South Korea.

Clinical Implications of New Drugs and Regimens for the Treatment of Drug-resistant Tuberculosis

The emergence of drug-resistant tuberculosis (TB) is a growing problem worldwide. The lack of safe and effective drugs, together with the frequent development of adverse drug reactions can result in worse outcomes. Therefore, new TB drugs able to bolster the current TB treatment regimen are urgently required. Novel drugs that are effective and safe against Mycobacterium tuberculosis are required to reduce the number of drugs and the duration of treatment in both drug-susceptible TB and multi-drug-resistant (MDR)-TB. This review covers promising novel TB drugs and regimens that are currently under development. Bedaquiline and delamanid are the most promising novel drugs for the treatment of MDR-TB, each having a high efficacy and tolerability. However, the best regimen for achieving better outcomes and reducing adverse drug reactions remains yet to be determined, with safety concerns regarding cardiac events due to QT prolongation still to be addressed. Pretomanid is a novel drug that potentially shortens the duration of treatment in both drug-susceptible and drug-resistant TB. Many regimens consisting of injection free drugs with shorter treatment duration compared to the conventional treatment are now undergoing clinical trials. Therefore a simple and short treatment with higher efficacy, and lesser adverse drug reactions and drug-drug interaction is expected for patients with MDR-TB.

Risk factors for poor multidrug-resistant tuberculosis treatment outcomes in Kyiv Oblast, Ukraine

Background

Ukraine is among ten countries with the highest burden of multidrug- resistant TB (MDR-TB) worldwide. Treatment success rates for MDR-TB in Ukraine remain below global success rates as reported by the World Health Organization. Few studies have evaluated predictors of poor MDR-TB outcomes in Ukraine.

Methods

We conducted a retrospective analysis of patients initiated on MDR-TB treatment in the Kyiv Oblast of Ukraine between January 01, 2012 and March 31st, 2015. We defined good treatment outcomes as cure or completion and categorized poor outcomes among those who died, failed treatment or defaulted. We used logistic regression analyses to identify baseline patient characteristics associated with poor MDR-TB treatment outcomes.

Results

Among 360 patients, 65 (18.1%) achieved treatment cure or completion while 131 (36.4%) died, 115 (31.9%) defaulted, and 37 (10.3%) failed treatment. In the multivariate analysis, the strongest baseline predictors of poor outcomes were HIV infection without anti-retroviral therapy (ART) initiation (aOR 10.07; 95% CI 1.20–84.45; p 0.03) and presence of extensively-drug resistant TB (aOR 9.19; 95% CI 1.17–72.06; p 0.03). HIV-positive patients initiated on ART were not at increased risk of poor outcomes (aOR 1.43; 95% CI 0.58–3.54; p 0.44). There was no statistically significant difference in risk of poor outcomes among patients who received baseline molecular testing with Gene Xpert compared to those who were not tested (aOR 1.31; 95% CI 0.63–2.73).

Conclusions

Rigorous compliance with national guidelines recommending prompt initiation of ART among HIV/TB co-infected patients and use of drug susceptibility testing results to construct treatment regimens can have a major impact on improving MDR-TB treatment outcomes in Ukraine.

Electronic supplementary material

The online version of this article (doi:10.1186/s12879-017-2230-2) contains supplementary material, which is available to authorized users.

Treatment Outcomes for Adolescents With Multidrug-Resistant Tuberculosis in Lima, Peru

Treatment outcomes for adolescents with multidrug-resistant tuberculosis are rarely reported and, to date, have been poor. Among 90 adolescents from Lima, Peru, 68 (75.6%) achieved cure or completion of treatment. Unsuccessful treatment was less common in the Peru cohort than previously described in the literature.

Yuen C, Rich ML, Evans SR. Totality of outcomes: A different paradigm in assessing interventions for treatment of tuberculosis

Conventional analytic methods used for tuberculosis (TB) outcomes research use standardized outcomes definitions and assess safety and efficacy separately. These methods are subject to important limitations. Conventionally utilized outcome definitions fail to capture important aspects of patients' treatment experience and obscure meaningful differences between patients. Assessing safety and efficacy separately fails to yield an objective risk–benefit comparison to guide clinical practice. We propose to address these issues through an analytic approach based on prioritized outcomes. This approach enables a more comprehensive and integrated assessment of TB interventions. It simultaneously considers a “totality of outcomes”, including clinical benefit, adverse events, and quality of life. These composite outcomes are ranked terms of overall desirability and compared using statistical methods for ordinal outcomes. Here we discuss the application of this approach to TB research, the considerations involved with prioritizing TB treatment outcomes, and the statistical methods involved in comparing prioritized outcomes.

Baseline Predictors of Treatment Outcomes in Children With Multidrug-Resistant Tuberculosis: A Retrospective Cohort Study

BACKGROUND

Globally, >30 000 children fall sick with multidrug-resistant (MDR) tuberculosis every year. Without robust pediatric data, clinical management follows international guidelines that are based on studies in adults and expert opinion. We aimed to identify baseline predictors of death, treatment failure, and loss to follow-up among children with MDR tuberculosis disease treated with regimens tailored to their drug susceptibility test (DST) result or to the DST result of a source case.

METHODS

This retrospective cohort study included all children ≤15 years old with confirmed and probable MDR tuberculosis disease who began tailored regimens in Lima, Peru, between 2005 and 2009. Using logistic regression, we examined associations between baseline patient and treatment characteristics and (1) death or treatment failure and (2) loss to follow-up.

RESULTS

Two hundred eleven of 232 (90.9%) children had known treatment outcomes, of whom 163 (77.2%) achieved cure or probable cure, 29 (13.7%) were lost to follow-up, 10 (4.7%) experienced treatment failure, and 9 (4.3%) died. Independent baseline predictors of death or treatment failure were the presence of severe disease (adjusted odds ratio [aOR], 4.96; 95% confidence interval [CI], 1.61-15.26) and z score ≤-1 (aOR, 3.39; 95% CI, 1.20-9.54). We did not identify any independent predictors of loss to follow-up.

CONCLUSIONS

High cure rates can be achieved in children with MDR tuberculosis using tailored regimens containing second-line drugs. However, children faced significantly higher risk of death or treatment failure if they had severe disease or were underweight. These findings highlight the need for early interventions that can improve treatment outcomes for children with MDR tuberculosis.

Aggressive Regimens Reduce Risk of Recurrence After Successful Treatment of MDR-TB

BACKGROUND

We sought to determine whether treatment with a "long aggressive regimen" was associated with lower rates of relapse among patients successfully treated for pulmonary multidrug-resistant tuberculosis (MDR-TB) in Tomsk, Russia.

METHODS

We conducted a retrospective cohort study of adult patients that initiated MDR-TB treatment with individualized regimens between September 2000 and November 2004, and were successfully treated. Patients were classified as having received "aggressive regimens" if their intensive phase consisted of at least 5 likely effective drugs (including a second-line injectable and a fluoroquinolone) used for at least 6 months post culture conversion, and their continuation phase included at least 4 likely effective drugs. Patients that were treated with aggressive regimens for a minimum duration of 18 months post culture conversion were classified as having received "long aggressive regimens." We used recurrence as a proxy for relapse because genotyping was not performed. After treatment, patients were classified as having disease recurrence if cultures grew MDR-TB or they re-initiated MDR-TB therapy. Data were analyzed using Cox proportional hazard regression.

RESULTS

Of 408 successfully treated patients, 399 (97.5%) with at least 1 follow-up visit were included. Median duration of follow-up was 42.4 months (interquartile range: 20.5-59.5), and there were 27 recurrence episodes. In a multivariable complete case analysis (n = 371 [92.9%]) adjusting for potential confounders, long aggressive regimens were associated with a lower rate of recurrence (adjusted hazard ratio: 0.22, 95% confidence interval, .05-.92).

CONCLUSIONS

Long aggressive regimens for MDR-TB treatment are associated with lower risk of disease recurrence.

Management and control of multidrug-resistant tuberculosis (MDR-TB): Addressing policy needs for India

Multidrug-resistant tuberculosis (MDR-TB) challenges TB control efforts because of delays in diagnosis plus its long-term treatment which has toxic effects. Of TB high-incidence countries, India carries the highest burden of MDR-TB cases. We describe policy issues in India concerning MDR-TB diagnosis and management in a careful review of the literature including a systematic review of studies on the prevalence of MDR-TB. Of 995 articles published during 2001-2016 and retrieved from the PubMed, only 20 provided data on the population prevalence of MDR-TB. We further reviewed and describe diagnostic criteria and treatment algorithms in use and endorsed by the Revised National TB Control Program of India. We discuss problems encountered in treating MDR-TB patients with standardized regimens. Finally, we provide realistic suggestions for policymakers and program planners to improve the management and control of MDR-TB in India.Journal of Public Health Policy advance online publication, 6 May 2016; doi:10.1057/jphp.2016.14.

Tuberculosis Case Fatality and Other Causes of Death among Multidrug-Resistant Tuberculosis Patients in a High HIV Prevalence Setting, 2000-2008, South Africa

INTRODUCTION

South Africa has the highest reported rates of multi-drug resistant TB in Africa, typified by poor treatment outcomes, attributable mainly to high default and death rates. Concomitant HIV has become the strongest predictor of death among MDR-TB patients, while anti-retroviral therapy (ART) has dramatically reduced mortality. TB Case fatality rate (CFR) is an indicator that specifically reports on deaths due to TB.

AIM

The aim of this paper was to investigate causes of death amongst MDR-TB patients, the contribution of conditions other than TB to deaths, and to determine if causes differ between HIV-uninfected patients, HIV-infected patients receiving ART and those without ART.

METHODS

We carried out a retrospective review of data captured from the register of the MDR-TB programme of the North West Province, South Africa. We included 671 patients treated between 2000-2008; 59% of the cohort was HIV-infected and 33% had received ART during MDR treatment. The register contained data on treatment outcomes and causes of death.

RESULTS

Treatment outcomes between HIV-uninfected cases, HIV-infected cases receiving ART and HIV-infected without ART differed significantly (p<0.000). The cohort death rate was 24%, 13% for HIV-uninfected cases and 31% for HIV-infected cases. TB caused most of the deaths, resulting in a cohort CFR of 15%, 9% for HIV-uninfected cases and 20% for HIV-infected cases. Cohort mortality rate due to other conditions was 2%. AIDS-conditions rather than TB caused significantly more deaths among HIV-infected cases receiving ART than those not (p = 0.02).

CONCLUSIONS

The deaths among HIV-infected individuals contribute substantially to the high death rate. ART co-therapy protected HIV-infected cases from death due to TB and AIDS-conditions. Mechanisms need to be in place to ensure that HIV-infected individuals are retained in care upon completion of their MDR-TB treatment.

Gyrase Mutations Are Associated with Variable Levels of Fluoroquinolone Resistance in Mycobacterium tuberculosis

Molecular diagnostics that rapidly and accurately predict resistance to fluoroquinolone drugs and especially later-generation agents promise to improve treatment outcomes for patients with multidrug-resistant tuberculosis and prevent the spread of disease. Mutations in the gyr genes are known to confer most fluoroquinolone resistance, but knowledge about the effects of gyr mutations on susceptibility to early- versus later-generation fluoroquinolones and about the role of mutation-mutation interactions is limited. Here, we sequenced the full gyrA and gyrB open reading frames in 240 multidrug-resistant and extensively drug-resistant tuberculosis strains and quantified their ofloxacin and moxifloxacin MIC by testing growth at six concentrations for each drug. We constructed a multivariate regression model to assess both the individual mutation effects and interactions on the drug MICs. We found that gyrB mutations contribute to fluoroquinolone resistance both individually and through interactions with gyrA mutations. These effects were statistically significant. In these clinical isolates, several gyrA and gyrB mutations conferred different levels of resistance to ofloxacin and moxifloxacin. Consideration of gyr mutation combinations during the interpretation of molecular test results may improve the accuracy of predicting the fluoroquinolone resistance phenotype. Further, the differential effects of gyr mutations on the activity of early- and later-generation fluoroquinolones requires further investigation and could inform the selection of a fluoroquinolone for treatment.

Efficacy and effect of free treatment on multidrug-resistant tuberculosis

Multidrug-resistant tuberculosis (MDR-TB) is a serious public health and social issue. It pertains to the type of tuberculosis that is resistant simultaneously to isoniazid and rifampicin. MDR-TB has a high mortality and is expensive to treat. The aim of the present study was to examine the therapeutic effects of individualized free treatment and the relevant influencing factors on the treatment outcome for MDR-TB. A prospective study module was used to analyze the therapeutic outcome of MDR-TB with individualized free treatment for 160 patients between 2011 and 2014. Statistical analysis was performed using the Chi-square or Fisher's exact test, and the odds ratio was calculated using a logistic regression analysis model. In total, 160 patients were enrolled in the study for treatment of MDR-TB. From these, 88 cases completed the course of treatment, and 70 cases were successfully treated. Of the remaining 72 cases, 37 cases exhibited treatment failure, 18 cases were suspended during treatment and 17 patients succumbed to the disease. The results showed that the confounding factors were: i) retreatment (p<0.05); ii) occurrence of diabetes (p<0.001); iii) lesion without improvement in radiography during treatment (p=0.001); iv) positive sputum culture for Mycobacterium tuberculosis after 3-month treatment (p<0.05); and v) termination of treatment due to adverse reaction (p<0.05). These factors were associated with poor treatment outcomes by logistic regression analysis. Adverse drug reaction was observed in 33 cases and treatment was terminated or changed permanently in 29 of these cases. The most common adverse reaction was liver function damage caused by pyrazinamide and leucopenia caused by rifabutin. One patient suffered from serious liver failure. In conclusion, the success rate of long treatment course for MDR-TB is not high due to many adverse reactions. Occurrence of diabetes is the main factor that caused poor efficacy.

Synthetic investigational new drugs for the treatment of tuberculosis

INTRODUCTION

Tuberculosis (TB) is a major global health concern. And while there are treatments already on the market, there is a demand for new drugs that are effective and safe against Mycobacterium tuberculosis, which reduce the number of drugs and the duration of treatment in both drug-susceptible TB and multidrug-resistant TB (MDR-TB).

AREA COVERED

This review covers promising novel investigational TB drugs that are currently under development. Specifically, the authors review the efficacy of novel agents for the treatment of TB in preclinical, phase I and phase II clinical trials. The authors also review the safety and tolerability profiles of these drugs.

EXPERT OPINION

Bedaquiline and delamanid are the most promising novel drugs for the treatment of MDR-TB, each having high efficacy and tolerability. However, the best regimen for achieving better outcomes and reducing adverse drug reactions remains to be determined, with safety concerns regarding cardiac events due to QT prolongation still to be addressed. Pretomanid is a novel drug that potentially shortens the duration of treatment in both drug-susceptible and drug-resistant TB in combination with moxifloxacin and pyrazinamide. Linezolid shows marked efficacy in the treatment of MDR-TB and extensively drug-resistant TB (XDR-TB), but the drug is known to cause significant adverse drug reactions, including peripheral neuropathy, optic neuropathy and myelosuppression. These adverse reactions must be considered prior to prescribing long-term usage of this drug.

Association between Regimen Composition and Treatment Response in Patients with Multidrug-Resistant Tuberculosis: A Prospective Cohort Study

BACKGROUND

For treating multidrug-resistant tuberculosis (MDR TB), the World Health Organization (WHO) recommends a regimen of at least four second-line drugs that are likely to be effective as well as pyrazinamide. WHO guidelines indicate only marginal benefit for regimens based directly on drug susceptibility testing (DST) results. Recent evidence from isolated cohorts suggests that regimens containing more drugs may be beneficial, and that DST results are predictive of regimen effectiveness. The objective of our study was to gain insight into how regimen design affects treatment response by analyzing the association between time to sputum culture conversion and both the number of potentially effective drugs included in a regimen and the DST results of the drugs in the regimen.

METHODS AND FINDINGS

We analyzed data from the Preserving Effective Tuberculosis Treatment Study (PETTS), a prospective observational study of 1,659 adults treated for MDR TB during 2005-2010 in nine countries: Estonia, Latvia, Peru, Philippines, Russian Federation, South Africa, South Korea, Thailand, and Taiwan. For all patients, monthly sputum samples were collected, and DST was performed on baseline isolates at the US Centers for Disease Control and Prevention. We included 1,137 patients in our analysis based on their having known baseline DST results for at least fluoroquinolones and second-line injectable drugs, and not having extensively drug-resistant TB. These patients were followed for a median of 20 mo (interquartile range 16-23 mo) after MDR TB treatment initiation. The primary outcome of interest was initial sputum culture conversion. We used Cox proportional hazards regression, stratifying by country to control for setting-associated confounders, and adjusting for the number of drugs to which patients' baseline isolates were resistant, baseline resistance pattern, previous treatment history, sputum smear result, and extent of disease on chest radiograph. In multivariable analysis, receiving an average of at least six potentially effective drugs (defined as drugs without a DST result indicating resistance) per day was associated with a 36% greater likelihood of sputum culture conversion than receiving an average of at least five but fewer than six potentially effective drugs per day (adjusted hazard ratio [aHR] 1.36, 95% CI 1.09-1.69). Inclusion of pyrazinamide (aHR 2.00, 95% CI 1.65-2.41) or more drugs to which baseline DST indicated susceptibility (aHR 1.65, 95% CI 1.48-1.84, per drug) in regimens was associated with greater increases in the likelihood of sputum culture conversion than including more drugs to which baseline DST indicated resistance (aHR 1.33, 95% CI 1.18-1.51, per drug). Including in the regimen more drugs for which DST was not performed was beneficial only if a minimum of three effective drugs was present in the regimen (aHR 1.39, 95% CI 1.09-1.76, per drug when three effective drugs present in regimen). The main limitation of this analysis is that it is based on observational data, not a randomized trial, and drug regimens varied across sites. However, PETTS was a uniquely large and rigorous observational study in terms of both the number of patients enrolled and the standardization of laboratory testing. Other limitations include the assumption of equivalent efficacy across drugs in a category, incomplete data on adherence, and the fact that the analysis considers only initial sputum culture conversion, not reversion or long-term relapse.

CONCLUSIONS

MDR TB regimens including more potentially effective drugs than the minimum of five currently recommended by WHO may encourage improved response to treatment in patients with MDR TB. Rapid access to high-quality DST results could facilitate the design of more effective individualized regimens. Randomized controlled trials are necessary to confirm whether individualized regimens with more than five drugs can indeed achieve better cure rates than current recommended regimens.

Treatment outcomes in multidrug resistant tuberculosis-human immunodeficiency virus Co-infected patients on anti-retroviral therapy at Sizwe Tropical Disease Hospital Johannesburg, South Africa

BACKGROUND

Multidrug resistant-tuberculosis (MDR-TB) is a threat to global tuberculosis control which is worsened by human immune-deficiency virus (HIV) co-infection. There is however paucity of data on the effects of antiretroviral treatment (ART) before or after starting MDR-TB treatment. This study determined predictors of mortality and treatment failure among HIV co-infected MDR-TB patients on ART.

METHODS

A retrospective medical record review of 1200 HIV co-infected MDR-TB patients admitted at Sizwe Tropical Disease Hospital, Johannesburg from 2007 to 2010 was performed. Chi-square test was used to determine treatment outcomes in HIV co-infected MDR-TB patients on ART. Multivariable logistic regression and Poisson models were used to determine predictors of mortality and treatment failure respectively.

RESULTS

Mortality was higher (21.8% vs. 15.4%) among patients who started ART before initiating MDR-TB treatment compared with patients initiated on ART after commencing MDR-TB treatment (p = 0.013). Factors significantly associated with mortality included: the use of ART before starting MDR-TB treatment (OR 1.65, 95% CI 1.02-2.73), severely-underweight (OR 3.71, 95% CI 1.89-7.29) and underweight (OR 2.35, 95% CI 1.30-4.26), cavities on chest x-rays at baseline (OR 1.76, 95% CI 1.08-2.94), presence of other opportunistic infections (OR 1.80, 95% CI 1.10-2.94) and presence of other co-morbidities (OR 2.26, 95% CI 1.20-4.21). Factors predicting failure were severe anaemia (IRR (OR 4.72, 95% CI 1.47-15), other co-morbidities (OR 2.39, 95% CI 1.05-5.43) and modified individualised regimen at baseline (OR 2.15, 95% CI 0.98-4.71).

CONCLUSIONS

High mortality among patients already on ART before initiating MDR-TB treatment is a worrisome development. Management of adverse-events, opportunistic infections and co-morbidities in these patients is important if the protective benefits of being on ART are to be maximized. There is the need to intensify intervention programmes targeted at early identification of MDR-TB, treatment initiation, drug monitoring and increasing adherence among HIV co-infected MDR-TB patients.

Multidrug-Resistant Tuberculosis Treatment Outcomes in Relation to Treatment and Initial Versus Acquired Second-Line Drug Resistance

BACKGROUND

Resistance to second-line drugs develops during treatment of multidrug-resistant (MDR) tuberculosis, but the impact on treatment outcome has not been determined.

METHODS

Patients with MDR tuberculosis starting second-line drug treatment were enrolled in a prospective cohort study. Sputum cultures were analyzed at a central reference laboratory. We compared subjects with successful and poor treatment outcomes in terms of (1) initial and acquired resistance to fluoroquinolones and second-line injectable drugs (SLIs) and (2) treatment regimens.

RESULTS

Of 1244 patients with MDR tuberculosis, 973 (78.2%) had known outcomes and 232 (18.6%) were lost to follow-up. Among those with known outcomes, treatment succeeded in 85.8% with plain MDR tuberculosis, 69.7% with initial resistance to either a fluoroquinolone or an SLI, 37.5% with acquired resistance to a fluoroquinolone or SLI, 29.3% with initial and 13.0% with acquired extensively drug-resistant tuberculosis (P < .001 for trend). In contrast, among those with known outcomes, treatment success increased stepwise from 41.6% to 92.3% as the number of drugs proven effective increased from ≤1 to ≥5 (P < .001 for trend), while acquired drug resistance decreased from 12% to 16% range, depending on the drug, down to 0%-2% (P < .001 for trend). In multivariable analysis, the adjusted odds of treatment success decreased 0.62-fold (95% confidence interval, .56-.69) for each increment in drug resistance and increased 2.1-fold (1.40-3.18) for each additional effective drug, controlling for differences between programs and patients. Specific treatment, patient, and program variables were also associated with treatment outcome.

CONCLUSIONS

Increasing drug resistance was associated in a logical stepwise manner with poor treatment outcomes. Acquired resistance was worse than initial resistance to the same drugs. Increasing numbers of effective drugs, specific drugs, and specific program characteristics were associated with better outcomes and less acquired resistance.

Medical Management of Drug-Resistant Tuberculosis

Drug-resistant tuberculosis (TB) is still a major threat worldwide. However, recent scientific advances in diagnostic and therapeutic tools have improved the management of drug-resistant TB. The development of rapid molecular testing methods allows for the early detection of drug resistance and prompt initiation of an appropriate treatment. In addition, there has been growing supportive evidence for shorter treatment regimens in multidrug-resistant TB; and for the first time in over 50 years, new anti-TB drugs have been developed. The World Health Organization has recently revised their guidelines, primarily based on evidence from a meta-analysis of individual patient data (n=9,153) derived from 32 observational studies, and outlined the recommended combination and correct use of available anti-TB drugs. This review summarizes the updated guidelines with a focus on the medical management of drug-resistant TB.

Counting pyrazinamide in regimens for multidrug-resistant tuberculosis

RATIONALE

For treatment of multidrug-resistant tuberculosis, World Health Organization (WHO) guidelines recommend four likely effective drugs plus pyrazinamide (PZA), irrespective of the likely effectiveness of PZA in an individual patient. Whether this regimen should be supplemented in the absence of likely PZA effectiveness is an open question.

OBJECTIVES

The objectives of this study were to examine (1) whether individuals receiving four likely effective drugs (based on documented susceptibility or no prior exposure) experienced higher mortality during the intensive phase of treatment than those receiving five likely effective drugs and (2) whether the WHO-recommended regimen (four likely effective drugs plus PZA) may be compromised in individuals in whom PZA is not likely effective.

METHODS

Among 668 patients, we compared the hazard of death across regimen groups characterized by the number of likely effective drugs and whether pyrazinamide was one of the likely effective drugs.

MEASUREMENTS AND MAIN RESULTS

Relative to five likely effective drugs, regimens of four likely effective drugs and the WHO-recommended regimen used in individuals in whom PZA was not likely effective were associated with higher mortality rates (respectively, adjusted hazard ratio [HR], 2.87; 95% confidence interval [CI], 1.35-6.09 and adjusted HR, 2.76; 95% CI, 0.92-8.27). The mortality rate for a regimen of five likely effective drugs with likely effective PZA was similar to that for the regimen of five likely effective drugs without PZA (HR, 1.00; 95% CI, 0.12-8.00).

CONCLUSIONS

Mortality may be reduced by the inclusion of five likely effective drugs, including an injectable, during the intensive phase of treatment. If PZA is unlikely to be effective in an individual patient, these results suggest adding a different, likely effective drug.

Predictors of cure among HIV co-infected multidrug-resistant TB patients at Sizwe Tropical Disease Hospital Johannesburg, South Africa

BACKGROUND

The global incidence of multidrug-resistant tuberculosis (MDR-TB) is rising, especially among HIV infected patients, despite intervention programs. Limited data are available on outcomes of MDR-TB treatment, specifically in a cohort of HIV co-infected patients in sub-Saharan Africa. The objective of this study was to determine the predictors of cure among MDR-TB HIV co-infected patients.

METHODS

A retrospective review of 1200 medical records of HIV co-infected MDR-TB patients was performed at Sizwe Tropical Disease Hospital, Johannesburg covering the period 2007 to 2010. Logistic regression analysis was done to identify predictors of cure.

RESULTS

Of 1137 patients included in the analysis, 29.8% (339/1137) were cured, 16.5% (188/1137) completed treatment, 22.3% (254/1137) defaulted treatment, 2.9% (33/1137) failed treatment and 22.7% (258/1137) died while on treatment. The remaining 5.7% (65/1137) were transferred-out or still-on-treatment. There was a significant interaction between sex and timing of antiretroviral treatment (ART) initiation (p=0.008). Factors predicting cure were male patients on ART prior to commencing MDR-TB treatment (OR 1.87, [1.11-3.13]), CD4(+) cell counts between 201-349 (OR 2.06, [1.10-3.84]) and ≥ 350 cells/mm³ (OR 1.98, [0.98-3.97]). Negative predictors of cure included the presence of cavitary lesions on chest x-rays (OR 0.55, [0.38-0.78]) and modified individualised regimen at baseline (OR 0.62, [0.42-0.92]).

CONCLUSIONS

Cure was higher in males on ART prior to initiating MDR-TB treatment compared with males on ART after initiating MDR-TB treatment. The inverse was the case among females. Therefore, future research should explore the biological and behavioural mechanisms that may possibly be responsible for this observed trend. This will help improve MDR-TB treatment outcomes in HIV co-infected patients on ART.

Concordance of Mycobacterium tuberculosis fluoroquinolone resistance testing: implications for treatment

Fluoroquinolone (FQ) drug susceptibility testing (DST) is an important step in the design of effective treatment regimens for multidrug-resistant tuberculosis. Here we compare ciprofloxacin, ofloxacin and moxifloxacin (MFX) resistance results from 226 multidrug-resistant samples. The low level of concordance observed suggests that DST should be performed for the specific FQ planned for clinical use. The results also support the new World Health Organization recommendation for testing MFX at a critical concentration of 2.0 μg/ml.

Delamanid when other anti-tuberculosis-treatment regimens failed due to resistance or tolerability

INTRODUCTION

The limited availability of effective drugs causes difficulties in the management of multidrug-resistant tuberculosis (MDR-TB) and novel therapeutic agents are needed. Delamanid , a new nitro-hydro-imidazooxazole derivative, inhibits mycolic acid synthesis. This review covers the efficacy and safety of delamanid for MDR-TB.

AREA COVERED

This paper reviews the pharmacological profile of delamanid and the results of clinical trials evaluating its efficacy for treating MDR-TB in combination with other anti-TB drugs. The drug's safety and tolerability profiles are also considered.

EXPERT OPINION

Delamanid showed potent activity against drug-susceptible and -resistant Mycobacterium tuberculosis in both in vitro and in vivo studies. In clinical trials, the drug showed significant early bactericidal activity in pulmonary TB patients, and increased culture conversion after 2 months of treatment in combination with an optimized background regimen in MDR-TB patients. In addition, decreased mortality was observed in MDR-TB patients who received > 6 months of delamanid treatment. The drug was generally tolerable, but QT prolongation should be monitored carefully using electrocardiograms and potassium levels. Therefore, delamanid could be used as part of an appropriate combination regimen for pulmonary MDR-TB in adult patients when an effective treatment regimen cannot otherwise be composed for reasons of resistance or tolerability.

Time to culture conversion and regimen composition in multidrug-resistant tuberculosis treatment

Sputum cultures are an important tool in monitoring the response to tuberculosis treatment, especially in multidrug-resistant tuberculosis. There has, however, been little study of the effect of treatment regimen composition on culture conversion. Well-designed clinical trials of new anti-tuberculosis drugs require this information to establish optimized background regimens for comparison. We conducted a retrospective cohort study to assess whether the use of an aggressive multidrug-resistant tuberculosis regimen was associated with more rapid sputum culture conversion. We conducted Cox proportional-hazards analyses to examine the relationship between receipt of an aggressive regimen for the 14 prior consecutive days and sputum culture conversion. Sputum culture conversion was achieved in 519 (87.7%) of the 592 patients studied. Among patients who had sputum culture conversion, the median time to conversion was 59 days (IQR: 31–92). In 480 patients (92.5% of those with conversion), conversion occurred within the first six months of treatment. Exposure to an aggressive regimen was independently associated with sputum culture conversion during the first six months of treatment (HR: 1.36; 95% CI: 1.10, 1.69). Infection with human immunodeficiency virus (HR 3.36; 95% CI: 1.47, 7.72) and receiving less exposure to tuberculosis treatment prior to the individualized multidrug-resistant tuberculosis regimen (HR: 1.58; 95% CI: 1.28, 1.95) were also independently positively associated with conversion. Tachycardia (HR: 0.77; 95% CI: 0.61, 0.98) and respiratory difficulty (HR: 0.78; 95% CI: 0.62, 0.97) were independently associated with a lower rate of conversion. This study is the first demonstrating that the composition of the multidrug-resistant tuberculosis treatment regimen influences the time to culture conversion. These results support the use of an aggressive regimen as the optimized background regimen in trials of new anti-TB drugs.

Commentary: a targets framework: dismantling the invisibility trap for children with drug-resistant tuberculosis

Tuberculosis (TB) is an airborne infectious disease that is both preventable and curable, yet it kills more than a million people every year. Children are highly vulnerable, but often invisible casualties. Drug-resistant forms of TB are on the rise globally, and children are as vulnerable as adults but less likely to be counted as cases of drug-resistant disease if they become sick. Four factors make children with drug-resistant TB 'invisible': first, the nature of the disease in children; second, deficiencies in existing diagnostic tools; third, overreliance on these tools; and fourth, our collective failure to deploy one effective tool for finding and treating children - contact investigation. We describe a nascent science-advocacy network - the Sentinel Project on Pediatric Drug-Resistant Tuberculosis - whose goal is to end child deaths from this disease. Provisional annual targets, focused on children exposed at home to multidrug-resistant TB, to be updated every year, constitute a framework to focus attention and collective actions at the community, national, and global levels. The targets in two age groups, under 5 and 5-14 years old, tell us the number of: (i) children who require complete evaluation for TB disease and infection; (ii) children who require treatment for TB disease; and (iii) children who would benefit from preventive therapy.

Treatment outcomes for patients with multidrug-resistant tuberculosis in post-earthquake Port-au-Prince, Haiti

We report outcomes and 12-month survival for the first cohort of patients to undergo multidrug-resistant tuberculosis (MDR-TB) treatment after the earthquake in Haiti. From March 3, 2010 to March 28, 2013, 110 patients initiated treatment of laboratory-confirmed MDR-TB at the Groupe Haïtien d'Etude du Sarcome de Kaposi et des Infections Opportunistes (GHESKIO) Center in Port-au-Prince, Haiti. Twenty-seven patients (25%) were human immunodeficiency virus (HIV)-positive. As of October 31, 2013, 95 (86%) patients were either cured or alive on treatment, 4 (4%) patients defaulted, and 11 (10%) patients died. Culture conversion occurred by 30 days in 14 (13%) patients, 60 days in 49 (45%) patients, and 90 days in 81 (74%) patients. The probabilities of survival to 12 months were 96% (95% confidence interval [95% CI] = 89-99) and 85% (95% CI = 64-94) for HIV-negative and -positive patients, respectively. Despite adverse conditions, outcomes for patients with MDR-TB are highly encouraging. Major efforts are underway to scale up community directly observed therapy and expand care to other regions of Haiti.

Multidrug-resistant tuberculosis in Western Australia, 1998-2012

OBJECTIVE To describe the epidemiology, clinical features, health care resource use, treatment and outcomes of multidrug-resistant tuberculosis (MDR-TB) cases diagnosed in Western Australia, compared with matched controls with drug-susceptible TB.

DESIGN, SETTING AND PATIENTS

Retrospective case-control study of all MDR-TB cases notified in WA between 1 January 1998 and 31 December 2012, compared with matched controls. Cases were identified and managed through the Western Australia Tuberculosis Control Program, including specialist TB services, the Mycobacterium Reference Laboratory and affiliated secondary and tertiary outpatient and inpatient medical services in WA.

MAIN OUTCOME MEASURES

Demographic characteristics, clinical manifestations, treatment, outcomes and health care resource use.

RESULTS

Sixteen MDR-TB cases were notified during the study period (1.2% of all TB notifications). The median age of patients with MDR-TB was 26 years, and 15 were born outside Australia. Patients with MDR-TB were more likely to have received previous treatment (25% v 2%; P = 0.006) and had longer delays to effective therapy (median, 48 v 21 days; P = 0.002) than controls. MDR-TB patients more frequently required hospitalisation (100% v 35%; P < 0.001) and were treated for longer (mean, 597 v 229 days). Adverse effects were more commonly reported in MDR-TB patients than controls (81% v 33%; P < 0.001). Treatment success was not significantly different between patients with MDR-TB and controls (75% v 84%; P = 0.72). No treatment failures or deaths were identified in either group.

CONCLUSION

MDR-TB remains uncommon in WA but its challenges are increasingly recognised. Despite delays in commencing effective therapy, MDR-TB is usually associated with treatment success. Adverse effects of medications are common, and treatment courses are long and complex. Specialist TB services should continue to be involved in management and prevention of all cases of MDR-TB.