Thank you for the opportunity to respond to the Correspondence by Drs. Chiang and Bam1 with regards to recurrent TB as a treatment outcome associated with smoking. We appreciate their interest in our article and their questions concerning the three manuscripts that were not included in our meta-analysis.2 The first, by Balian et al.2 was not identified in our updated search in August of 2017. The two other articles, by Masjedi et al.3 and Leung et al.,4 were excluded from our meta-analysis as they included former smokers in their smoking definitions and models. Our meta-analysis attempted to focus solely on current smokers and we excluded articles that specifically identified their exposure group as including former smokers. However, we agree that former smoking may be an important risk factor to consider in future research regarding smoking and TB treatment outcomes. | | We also concur with the conclusion that recurrent TB is an important treatment outcome that should be considered in the context of smoking behavior. This was not explored in our meta-analysis, but we encourage others to include this in future research and reviews of this topic.

BACKGROUND: Cigarette smoking contributes to tuberculosis (TB) epidemiology. However, limited evidence exists on how smoking impacts TB treatment outcomes such as treatment loss to follow-up and culture conversion.METHODS: This meta-analysis assessed current evidence of the impact of active cigarette smoking on TB treatment outcomes. PubMed, Scopus, Embase, and the Cochrane Library were searched for English-language articles published from database inception through 2017. Articles addressing active pulmonary TB and cigarette smoking were identified and data abstracted. Smokers were defined as those who smoked every day or some days at the time of interview/diagnosis. Non-smokers did not smoke at the time of interview/diagnosis. Unfavorable outcomes included any outcome other than cure or completion of TB treatment. Three different data sets were examined: 8 articles addressing unfavorable treatment outcomes, 9 analyzing only treatment loss to follow-up, and 5 addressing delayed smear or culture conversion. Studies that had <20 subjects or that addressed only populations with comorbidities were excluded.RESULTS: We identified 1030 studies; 21 studies fulfilled the inclusion/exclusion criteria. Smokers had greater odds of unfavorable outcomes (pooled odds ratio [pOR] 1.23, 95%CI 1.14-1.33), delayed smear or culture conversion (pOR 1.55, 95%CI 1.04-2.07), and treatment loss to follow-up (pOR 1.35, 95%CI 1.21-1.50).CONCLUSION: Cigarette smoking is associated with negative treatment results and delayed conversion to negative smear or culture, suggesting smoking is an important factor for consideration in TB elimination efforts.

Comprehensive guidelines for treatment of latent tuberculosis infection (LTBI) among persons living in the United States were last published in 2000 (American Thoracic Society. CDC targeted tuberculin testing and treatment of latent tuberculosis infection. Am J Respir Crit Care Med 2000;161:S221-47). Since then, several new regimens have been evaluated in clinical trials. To update previous guidelines, the National Tuberculosis Controllers Association (NTCA) and CDC convened a committee to conduct a systematic literature review and make new recommendations for the most effective and least toxic regimens for treatment of LTBI among persons who live in the United States.The systematic literature review included clinical trials of regimens to treat LTBI. Quality of evidence (high, moderate, low, or very low) from clinical trial comparisons was appraised using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) criteria. In addition, a network meta-analysis evaluated regimens that had not been compared directly in clinical trials. The effectiveness outcome was tuberculosis disease; the toxicity outcome was hepatotoxicity. Strong GRADE recommendations required at least moderate evidence of effectiveness and that the desirable consequences outweighed the undesirable consequences in the majority of patients. Conditional GRADE recommendations were made when determination of whether desirable consequences outweighed undesirable consequences was uncertain (e.g., with low-quality evidence).These updated 2020 LTBI treatment guidelines include the NTCA- and CDC-recommended treatment regimens that comprise three preferred rifamycin-based regimens and two alternative monotherapy regimens with daily isoniazid. All recommended treatment regimens are intended for persons infected with Mycobacterium tuberculosis that is presumed to be susceptible to isoniazid or rifampin. These updated guidelines do not apply when evidence is available that the infecting M. tuberculosis strain is resistant to both isoniazid and rifampin; recommendations for treating contacts exposed to multidrug-resistant tuberculosis were published in 2019 (Nahid P, Mase SR Migliori GB, et al. Treatment of drug-resistant tuberculosis. An official ATS/CDC/ERS/IDSA clinical practice guideline. Am J Respir Crit Care Med 2019;200:e93-e142). The three rifamycin-based preferred regimens are 3 months of once-weekly isoniazid plus rifapentine, 4 months of daily rifampin, or 3 months of daily isoniazid plus rifampin. Prescribing providers or pharmacists who are unfamiliar with rifampin and rifapentine might confuse the two drugs. They are not interchangeable, and caution should be taken to ensure that patients receive the correct medication for the intended regimen. Preference for these rifamycin-based regimens was made on the basis of effectiveness, safety, and high treatment completion rates. The two alternative treatment regimens are daily isoniazid for 6 or 9 months; isoniazid monotherapy is efficacious but has higher toxicity risk and lower treatment completion rates than shorter rifamycin-based regimens.In summary, short-course (3- to 4-month) rifamycin-based treatment regimens are preferred over longer-course (6-9 month) isoniazid monotherapy for treatment of LTBI. These updated guidelines can be used by clinicians, public health officials, policymakers, health care organizations, and other state and local stakeholders who might need to adapt them to fit individual clinical circumstances.

Background: The American Thoracic Society, U.S. Centers for Disease Control and Prevention, European Respiratory Society, and Infectious Diseases Society of America jointly sponsored this new practice guideline on the treatment of drug-resistant tuberculosis (DR-TB). The document includes recommendations on the treatment of multidrug-resistant TB (MDR-TB) as well as isoniazid-resistant but rifampin-susceptible TB.Methods: Published systematic reviews, meta-analyses, and a new individual patient data meta-analysis from 12,030 patients, in 50 studies, across 25 countries with confirmed pulmonary rifampin-resistant TB were used for this guideline. Meta-analytic approaches included propensity score matching to reduce confounding. Each recommendation was discussed by an expert committee, screened for conflicts of interest, according to the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) methodology.Results: Twenty-one Population, Intervention, Comparator, and Outcomes questions were addressed, generating 25 GRADE-based recommendations. Certainty in the evidence was judged to be very low, because the data came from observational studies with significant loss to follow-up and imbalance in background regimens between comparator groups. Good practices in the management of MDR-TB are described. On the basis of the evidence review, a clinical strategy tool for building a treatment regimen for MDR-TB is also provided.Conclusions: New recommendations are made for the choice and number of drugs in a regimen, the duration of intensive and continuation phases, and the role of injectable drugs for MDR-TB. On the basis of these recommendations, an effective all-oral regimen for MDR-TB can be assembled. Recommendations are also provided on the role of surgery in treatment of MDR-TB and for treatment of contacts exposed to MDR-TB and treatment of isoniazid-resistant TB.

The treatment of drug-resistant tuberculosis (TB) is complicated and has evolved significantly in the past decade with the advent of rapid molecular tests and updated evidence-based guidelines of the World Health Organization and other organizations. The latest recommendations incorporate the use of new drugs and regimens that maximize efficacy and minimize toxicity to improve treatment outcomes for the patients. This article provides an overview of the latest published strategies for clinical and programmatic management of drug-resistant TB.

Background: Tuberculosis (TB) Regional Training and Medical Consultation Centers (RTMCCs) were established in 2005 for TB medical consultation, training and education in the United States. A medical consultation database (MCD) captured all consultations provided by RTMCCs; we report on those provided from June 1, 2010 to May 31, 2014. Method(s): All MCD consultations during 2010-2014 were categorized into: provider type, setting, consultation topic, and patient age. We analyzed data frequencies and performed subgroup analyses by RTMCC, by TB incidence for the geographical area, and by year of consultation. End-user satisfaction was assessed by a 2016 telephone evaluation of RTMCC services. Result(s): A total of 11,074 consultations were delivered, with 10,754 (97.1%) in the U.S. and its current or former territories. Of these, 6018 (56%) were for high, 2443 (22.7%) for medium, and 2293 (21.3%) for low TB incidence settings. Most were for adults (81.3%) and answered within 24 h (96.2%). Nearly 2/3 consultations originated from health departments; providers included mostly physicians (44.3%) or nurses (37.6%). Common consult categories included TB disease (47.7%), case management (29.8%), latent TB infection (19.3%), diagnosis (16.1%), pharmacology (14.7%) and adverse side effects (14.3%). Among adverse side effects, hepatotoxicity was most common (39.6%). Volume and nature of consult requests remained relatively stable over the four-year period. Feedback from a 2016 CDC evaluation indicated overall satisfaction with RTMCC medical consultation services. Conclusion(s): RTMCCS were an important source of TB medical consultation over the time-frame of this assessment and provided quality expert consultation within 24 h. RMTCCs represent a reservoir of TB subject-matter expertise in the United States.

The End TB Strategy envisions a world free of tuberculosis-zero deaths, disease and suffering due to tuberculosis by 2035. This requires reducing the global tuberculosis incidence from >1250 cases per million people to <100 cases per million people within the next two decades. Expanding testing and treatment of tuberculosis infection is critical to achieving this goal. In high-burden countries, like India, the implementation of tuberculosis preventive treatment (TPT) remains a low priority. In this analysis article, we explore potential challenges and solutions of implementing TPT in India. The next chapter in tuberculosis elimination in India will require cost-effective and sustainable interventions aimed at tuberculosis infection. This will require constant innovation, locally driven solutions to address the diverse and dynamic tuberculosis epidemiology and persistent programme monitoring and evaluation. As new tools, regimens and approaches emerge, midcourse adjustments to policy and practice must be adopted. The development and implementation of new tools and strategies will call for close collaboration between local, national and international partners-both public and private-national health authorities, non-governmental organisations, research community and the diagnostic and pharmaceutical industry. Leading by example, India can contribute to global knowledge through operational research and programmatic implementation for combating tuberculosis infection.

Background: Evidence-based recommendations for treating persons having presumed latent tuberculosis infection (LTBI) after contact to infectious multidrug-resistant tuberculosis (MDR TB) are lacking because published data consist of small observational studies. TB incidence in persons treated for latent multidrug-resistant-TB infection (MDR LTBI) is unknown. Methods: We conducted a systematic review of studies published (1/1/1994-12/31/2014) to analyze TB incidence, treatment completion and discontinuation, and cost effectiveness. We considered contacts with LTBI effectively treated if they were on ≥ one medication to which their MDR-TB strain was likely susceptible. We selected studies that compared treatment versus non-treatment outcomes and performed meta-analysis to estimate the relative risk of TB incidence and its 95% confidence interval. Results: We abstracted data from 21 articles that met inclusion criteria. Six articles presented outcomes for contacts who were treated compared with those not treated for MDR LTBI; 10 presented outcomes only for treated contacts, and five presented outcomes only for untreated contacts. The estimated MDR TB incidence reduction was 90% (9%-99%) using data from five comparison studies. We also found high treatment discontinuation rates due to adverse effects in persons taking pyrazinamide-containing regimens. Cost effectiveness was greatest using a fluoroquinolone/ethambutol combination regimen. Conclusions: Few studies met inclusion criteria, therefore results should be cautiously interpreted. We found a reduced risk of TB incidence with treatment for MDR LTBI, suggesting effectiveness in prevention of progression to MDR TB, and confirmed cost effectiveness. However, we found that pyrazinamide-containing MDR-LTBI regimens often resulted in treatment discontinuation due to adverse effects.

BACKGROUND: In the Federated States of Micronesia (FSM) and then the Republic of the Marshall Islands (RMI), levofloxacin pharmacokinetics (PK) were studied in children receiving directly observed once-daily regimens (10 mg/kg, age <5 years; 15 20 mg/kg, age ≤5 years) for either multidrug-resistant tuberculosis (MDR TB) disease or latent infection after MDR TB exposure, to inform future dosing strategies. METHODS: Blood samples were collected at 0 (RMI only), 1, 2, and 6 hours (50 children, aged 6 months to 15 years) after oral levofloxacin at >6 weeks of treatment. Clinical characteristics and levofloxacin Cmax, elimination half-life (t1/2), and area under the curve from 0 to 24 hours (AUC0-24 hours * microg/mL) were correlated to determine optimal dosage and to examine associations. Population PK and target attainment were modeled. With results from FSM, dosages were increased in RMI toward the target maximal drug concentration (Cmax) for Mycobacterium tuberculosis, 8-12 microg/ml. RESULTS: Cmax correlated linearly with per-weight dosage. Neither Cmax nor t1/2 was associated with gender, age, body mass index, concurrent medications, or pre-dose meals. At levofloxacin dosage of 15-20 mg/kg, Cmax ≥ 8 microg/ml was observed, and modeling corroborated a high target attainment across the ratio of the area under the free-concentration-versus-time curve to minimum inhibitory concentration (fAUCss,0-24/MIC) values. CONCLUSIONS: Levofloxacin dosage should be 15-20 mg/kg for Cmax ≥ 8 microg/ml and a high target attainment across fAUCss,0-24/MIC values in children ≥2 years of age.

BACKGROUND: With the emergence of multidrug-resistant (MDR-) and extensively drug-resistant tuberculosis (XDR-TB), surgery, which had been replaced by short-course chemotherapy, is again being considered a viable treatment option. OBJECTIVE: To assess the literature on the effectiveness of surgical interventions in the treatment of drug-resistant TB. METHODS: Medline, EMBASE, and PubMed were searched from 1975 to April 2012 in addition to hand searching reference lists, and the International Journal of Tuberculosis and Lung Disease. Potentially relevant studies were assessed according to pre-defined eligibility criteria: MDR- and XDR-TB patients undergoing surgical and non-surgical treatment. Treatment outcomes were extracted according to internationally accepted definitions and included in meta-analyses using random effects models. RESULTS: Summary meta-analysis of 24 comparison studies revealed a significant association between surgery and successful treatment compared to non-surgical interventions (OR 2.24, 95%CI 1.68-2.97). A meta-analysis from 23 single-arm studies demonstrated that respectively 92% (95%CI 88.1-95) and 87% (95%CI 83-91) of surgical patients achieved successful short- and long-term outcomes. Subgroup analyses showed that favorable surgical outcomes were associated with increased drug resistance in studies reporting surgical and non-surgical treatment outcomes. CONCLUSIONS: While the results suggest that surgical intervention is associated with successful treatment outcomes in patients with drug-resistant TB, there is insufficient evidence to recommend surgery plus chemotherapy over chemotherapy alone, to evaluate the potential harm from surgery and to determine the optimal conditions for surgery. Controlled studies are needed to better assess the effectiveness of surgery and to investigate other contextual issues.