Cost-effectiveness of 3 months of weekly rifapentine and isoniazid compared with other standard treatment regimens for latent tuberculosis infection: a decision analysis study

Cost-effectiveness of latent tuberculosis infection testing and treatment with 6-week regimen among key population in rural communities in China: a decision analysis study

PURPOSE

Several model studies suggested the implementation of latent tuberculosis infection (LTBI) testing and treatment could greatly reduce the incidence of tuberculosis (TB) and achieve the 2035 target of the "End TB" Strategy in China. The present study aimed to evaluate the cost-effectiveness of LTBI testing and TB preventive treatment among key population (≥ 50 years old) susceptible to TB at community level in China.

METHODS

A Markov model was developed to investigate the cost-effectiveness of LTBI testing using interferon gamma release assay (IGRA) and subsequent treatment with 6-month daily isoniazid regimen (6H) (as a standard regimen for comparison) or 6-week twice-weekly rifapentine and isoniazid regimen (6-week H2P2) in a cohort of 10,000 adults with an average initial age of 50 years.

RESULTS

In the base-case analysis, LTBI testing and treatment with 6H was dominated (i.e., more expensive with a lower quality-adjusted life year (QALY)) by LTBI testing and treatment with 6-week H2P2. LTBI testing and treatment with 6-week H2P2 was more effective than no intervention at a cost of $20,943.81 per QALY gained, which was below the willingness-to-pay (WTP) threshold of $24,211.84 per QALY gained in China. The one-way sensitivity analysis showed the change of LTBI prevalence was the parameter that most influenced the results of the incremental cost-effectiveness ratios (ICERs).

CONCLUSION

As estimated by a Markov model, LTBI testing and treatment with 6-week H2P2 was cost-saving compared with LTBI testing and treatment with 6H, and it was considered to be a cost-effective option for TB control in rural China.

Hybrid use of Raman spectroscopy and artificial neural networks to discriminate Mycobacterium bovis BCG and other Mycobacteriales

Even in the face of the COVID-19 pandemic, Tuberculosis (TB) continues to be a major public health problem and the 2nd biggest infectious cause of death worldwide. There is, therefore, an urgent need to develop effective TB diagnostic methods, which are cheap, portable, sensitive and specific. Raman spectroscopy is a potential spectroscopic technique for this purpose, however, so far, research efforts have focused primarily on the characterisation of Mycobacterium tuberculosis and other Mycobacteria, neglecting bacteria within the microbiome and thus, failing to consider the bigger picture. It is paramount to characterise relevant Mycobacteriales and develop suitable analytical tools to discriminate them from each other. Herein, through the combined use of Raman spectroscopy and the self-optimising Kohonen index network and further multivariate tools, we have successfully undertaken the spectral analysis of Mycobacterium bovis BCG, Corynebacterium glutamicum and Rhodoccocus erythropolis. This has led to development of a useful tool set, which can readily discern spectral differences between these three closely related bacteria as well as generate a unique spectral barcode for each species. Further optimisation and refinement of the developed method will enable its application to other bacteria inhabiting the microbiome and ultimately lead to advanced diagnostic technologies, which can save many lives.

The Global Expansion of LTBI Screening and Treatment Programs: Exploring Gaps in the Supporting Economic Evidence

The global burden of latent TB infection (LTBI) and the progression of LTBI to active TB disease are important drivers of ongoing TB incidence. Addressing LTBI through screening and TB preventive treatment (TPT) is critical in order to end the TB epidemic by 2035. Given the limited resources available to health ministries around the world in the fight against TB, we must consider economic evidence for LTBI screening and treatment strategies to ensure that limited resources are used to achieve the biggest health impact. In this narrative review, we explore key economic evidence around LTBI screening and TPT strategies in different populations to summarize our current understanding and highlight gaps in existing knowledge. When considering economic evidence supporting LTBI screening or evaluating different testing approaches, a disproportionate number of economic studies have been conducted in high-income countries (HICs), despite the vast majority of TB burden being borne in low- and middle-income countries (LMICs). Recent years have seen a temporal shift, with increasing data from low- and middle-income countries (LMICs), particularly with regard to targeting high-risk groups for TB prevention. While LTBI screening and prevention programs can come with extensive costs, targeting LTBI screening among high-risk populations, such as people living with HIV (PLHIV), children, household contacts (HHC) and immigrants from high-TB-burden countries, has been shown to consistently improve the cost effectiveness of screening programs. Further, the cost effectiveness of different LTBI screening algorithms and diagnostic approaches varies widely across settings, leading to different national TB screening policies. Novel shortened regimens for TPT have also consistently been shown to be cost effective across a range of settings. These economic evaluations highlight key implementation considerations such as the critical nature of ensuring high rates of adherence and completion, despite the costs associated with adherence programs not being routinely assessed and included. Digital and other adherence support approaches are now being assessed for their utility and cost effectiveness in conjunction with novel shortened TPT regimens, but more economic evidence is needed to understand the potential cost savings, particularly in settings where directly observed preventive therapy (DOPT) is routinely conducted. Despite the growth of the economic evidence base for LTBI screening and TPT recently, there are still significant gaps in the economic evidence around the scale-up and implementation of expanded LTBI screening and treatment programs, particularly among traditionally hard-to-reach populations.

Management of Tuberculosis Infection: Current Situation, Recent Developments and Operational Challenges

Tuberculosis infection (TBI) is defined as a state of infection in which individuals host live Mycobacterium tuberculosis with or without clinical signs of active TB. It is now understood as a dynamic process covering a spectrum of responses to infection resulting from the interaction between the TB bacilli and the host immune system. The global burden of TBI is about one-quarter of the world’s population, representing a reservoir of approximately 2 billion people. On average, 5–10% of people who are infected will develop TB disease over the course of their lives, but this risk is enhanced in a series of conditions, such as co-infection with HIV. The End-TB strategy promotes the programmatic management of TBI as a crucial endeavor to achieving global targets to end the TB epidemic. The current development of new diagnostic tests capable of discriminating between simple TBI and active TB, combined with novel short-course preventive treatments, will help achieve this goal. In this paper, we present the current situation and recent developments of management of TBI and the operational challenges.

High dose rifampin for 2 months vs standard dose rifampin for 4 months, to treat TB infection: Protocol of a 3-arm randomized trial (2R2)

INTRODUCTION

Tuberculosis preventive treatment (TPT) is an essential component for TB elimination. In order to be successfully implemented on a large scale, TPT needs to be safe, affordable and widely available in all settings. Short TPT regimens, that are less burdensome than longer regimens, to patients and health systems, are needed. Doses of rifampin higher than the standard 10mg/kg/day were tolerated in studies to reduce duration of treatment for tuberculosis disease (TBD). The objective of this trial is to test the safety of high dose rifampin monotherapy to shorten the duration of the currently recommended TPT of 4 months rifampin.

METHODS AND ANALYSIS

This is a phase 2b, randomised, controlled, parallel group, superiority, partially-blind trial. Primary outcomes are completion of treatment (as a proxy measure of tolerability) and safety. The two experimental arms comprise 60 days of (i) 20mg/kg/day or (ii) 30mg/kg/day rifampin; the control arm comprises 120 days of 10mg/kg/day rifampin as TPT. Participants are adults and children 10 years or older, eligible for TPT. Completion is the primary outcome, measured by pill count and is defined as taking minimum of 80% of treatment in 120% of allowed time; it will be tested for superiority by logistic regression. Safety outcome comprises proportion of grade 3-5 adverse events and grade 1-2 rash, adjudicated related to study drug, and resulting in permanent drug discontinuation; compared for non-inferiority between each of the two high dose arms and the standard arm, using Poisson regression. A sample size of 1,359 participants will give 80% power to detect a 10% difference in completion rates and a 1% difference in the safety outcome. The study is conducted in Canada, Indonesia and Vietnam. Enrolment is ongoing at all sites.

ETHICS AND DISSEMINATION

Approvals from a local research ethics board (REB) have been obtained at all participating sites and by the trial coordinating centre. Approval has been given by drug regulatory agencies in Canada and Indonesia and by Ministry of Health in Vietnam; participants give written informed consent before participation. All data collected are non-nominal. Primary results will be submitted for publication in a peer-reviewed journal when all participants have completed treatment; results of secondary outcomes will be submitted for publication at the end of study; all sites will receive the final data of participants from their sites.

TRIAL REGISTRATION

Trial registered in ClinicalTrials.gov (Identifier: NCT03988933). Coordinating center is the study team working at McGill University Health Center-Research Institute (MUHC-RI); sponsor is the MUHC-RI; funding has been granted by Canadian Institute of Health Research (FDN-143350).

A scoping review on the risk of tuberculosis in specific population groups: can we expand the World Health Organization recommendations?

Since 2015, the World Health Organization (WHO) has recommended prioritising testing and treatment of tuberculosis (TB) infection (TBI) in 11 high-risk groups. With new options emerging for TB preventive treatment, we conducted a scoping review, in consultation with the WHO's Global Tuberculosis Programme, to explore the evidence for other population groups at potentially high risk of progression to active TB. We searched six databases for preprints and articles published between 2000 and August 2022. 18 out of 33 668 screened records were included (six meta-analyses and 12 original research studies). Most were observational studies reporting the incidence of active TB in a risk group versus control. Glomerular diseases had the strongest association with active TB (standardised incidence ratio 23.36, 95% CI 16.76-31.68) based on an unpublished study. Other conditions associated with increased risk of active TB included hepatitis C, malignancies, diabetes mellitus, rheumatoid arthritis and vitamin D deficiency. Corticosteroid use was also associated with increased risk in several studies, although heterogeneous definitions of exposure and indications for use challenge interpretation. Despite methodological limitations of the identified studies, expanding the recommendations for TBI screening and treatment to new risk groups such as those reported here should be considered. Further group-specific systematic reviews may provide additional data for decision-making.

Cost-effectiveness of 3-months isoniazid and rifapentine compared to 9-months isoniazid for latent tuberculosis infection: a systematic review

BACKGROUND

We conducted a systematic review examining the cost effectiveness of a 3-month course of isoniazid and rifapentine, known as 3HP, given by directly observed treatment, compared to 9 months of isoniazid that is directly observed or self-administered, for latent tuberculosis infection. 3HP has shown to be effective in reducing progression to active tuberculosis and like other short-course regimens, has higher treatment completion rates compared to standard regimens such as 9 months of isoniazid. Decision makers would benefit from knowing if the higher up-front costs of rifapentine and of the human resources needed for directly observed treatment are worth the investment for improved outcomes.

METHODS

We searched PubMed, Embase, CINAHL, LILACS, and Web of Science up to February 2022 with search concepts combining latent tuberculosis infection, directly observed treatment, and cost or cost-effectiveness. Studies included were in English or French, on human subjects, with latent tuberculosis infection, provided information on specified anti-tubercular therapy regimens, had a directly observed treatment arm, and described outcomes with some cost or economic data. We excluded posters and abstracts, treatment for multiple drug resistant tuberculosis, and combined testing and treatment strategies. We then restricted our findings to studies examining directly-observed 3HP for comparison. The primary outcome was the cost and cost-effectiveness of directly-observed 3HP.

RESULTS

We identified 3 costing studies and 7 cost-effectiveness studies. The 3 costing studies compared directly-observed 3HP to directly-observed 9 months of isoniazid. Of the 7 cost-effectiveness studies, 4 were modelling studies based in high-income countries; one study was modelled on a high tuberculosis incidence population in the Canadian Arctic, using empiric costing data from that setting; and 2 studies were conducted in a low-income, high HIV-coinfection rate population. In five studies, directly-observed 3HP compared to self-administered isoniazid for 9 months in high-income countries, has incremental cost-effectiveness ratios that range from cost-saving to $5418 USD/QALY gained. While limited, existing evidence suggests 3HP may not be cost-effective in low-income, high HIV-coinfection settings.

CONCLUSION

Cost-effectiveness should continue to be assessed for programmatic planning and scale-up, and may vary depending on existing systems and local context, including prevalence rates and patient expectations and preferences.

Systematic review with network meta-analysis on the treatments for latent tuberculosis infection in children and adolescents

BACKGROUND

We aimed to synthesize the evidence on the efficacy and safety of different treatment regimens for latent tuberculosis infection (LTBI) in children and adolescents.

METHODS

A systematic review with network meta-analysis was performed (CRD142933). Searches were conducted in Pubmed and Scopus (Nov-2021). Randomized controlled trials comparing treatments for LTBI (patients up to 15 years), and reporting data on the incidence of the disease, death or adverse events were included. Networks using the Bayesian framework were built for each outcome of interest. Results were reported as odds ratio (OR) with 95% credibility intervals (CrI). Rank probabilities were calculated via the surface under the cumulative ranking analysis (SUCRA) (Addis-v.1.16.8). GRADE approach was used to rate evidence's certainty.

RESULTS

Seven trials (n = 8696 patients) were included. Placebo was significantly associated with a higher incidence of tuberculosis compared to all active therapies. Combinations of isoniazid (15-25 mg/kg/week) plus rifapentine (300-900 mg/week), followed by isoniazid plus rifampicin (10 mg/kg/day) were ranked as best approaches with lower probabilities of disease incidence (10% and 19.5%, respectively in SUCRA) and death (20%). Higher doses of isoniazid monotherapy were significantly associated to more deaths (OR 18.28, 95% ICr [1.02, 48.60] of 4-6 mg/kg/day vs. 10 mg/kg/3x per week).

CONCLUSIONS

Combined therapies of isoniazid plus rifapentine or rifampicin for short-term periods should be used as the first-line approach for treating LTBI in children and adolescents. The use of long-term isoniazid as monotherapy and at higher doses should be avoided for this population.

Preventive Treatment for Household Contacts of Drug-Susceptible Tuberculosis Patients

People who live in the household of someone with infectious pulmonary tuberculosis are at a high risk of tuberculosis infection and subsequent progression to tuberculosis disease. These individuals are prioritized for contact investigation and tuberculosis preventive treatment (TPT). The treatment of TB infection is critical to prevent the progression of infection to disease and is prioritized in household contacts. Despite the availability of TPT, uptake in household contacts is poor. Multiple barriers prevent the optimal implementation of these policies. This manuscript lays out potential next steps for closing the policy-to-implementation gap in household contacts of all ages.

Effect of implementation of a 12 dose once-weekly treatment (3HP) in addition to standard regimens to prevent TB on completion rates: Interrupted time series design

OBJECTIVE

We aimed to determine if offering a 12 dose once-weekly treatment (3HP) as an additional treatment option would result in an increase in the overall proportion of patients completing TB preventive treatment (TPT) above the baseline rate.

METHODS

We analyzed outcomes in consecutive adults referred to a TB clinic from January 2010 to May 2019. Starting December 2016, 3HP was offered as an alternative to standard clinic regimens which included 9 months of daily isoniazid or 4 months of daily rifampin. The primary outcome was the proportion who completed TPT among all patients who started treatment. Using segmented autoregression analysis we compared completion at the end of the study to projected completion had the intervention not been introduced.

RESULTS

A total of 2803 adults were referred for assessment over the study period. There was an absolute increase in completions among all of those who started a treatment of 19.0% at the end of the study between the observed intervention completion rate and the projected completion rate from the baseline study period (the completion rate had the 3HP intervention not been introduced) (76% observed vs 57% projected, 95% CI 6.6 to 31.4%, p = 0.004) and an absolute increase among those who were offered treatment of 17.3% 95% CI, 2.3 to 32.3%, p = 0.025).

INTERPRETATION

The introduction of 3HP for TPT as an alternative to the regular regimens offered resulted in a significant increase in the proportion of patients completing treatment. Our study provides evidence to support accelerated use of 3HP in Canada.

Modeling the Cost-Effectiveness of Latent Tuberculosis Screening and Treatment Strategies in Recent Migrants to a Low-Incidence Setting

Many tuberculosis (TB) cases in low-incidence settings are attributed to reactivation of latent TB infection (LTBI) acquired overseas. We assessed the cost-effectiveness of community-based LTBI screening and treatment strategies in recent migrants to a low-incidence setting (Australia). A decision-analytical Markov model was developed that cycled 1 migrant cohort (≥11-year-olds) annually over a lifetime from 2020. Postmigration/onshore and offshore (screening during visa application) strategies were compared with existing policy (chest x-ray during visa application). Outcomes included TB cases averted and discounted cost per quality-adjusted life-year (QALY) gained from a health-sector perspective. Most recent migrants are young adults and cost-effectiveness is limited by their relatively low LTBI prevalence, low TB mortality risks, and high emigration probability. Onshore strategies cost at least $203,188 (Australian) per QALY gained, preventing approximately 2.3%-7.0% of TB cases in the cohort. Offshore strategies (screening costs incurred by migrants) cost at least $13,907 per QALY gained, preventing 5.5%-16.9% of cases. Findings were most sensitive to the LTBI treatment quality-of-life decrement (further to severe adverse events); with a minimal decrement, all strategies caused more ill health than they prevented. Additional LTBI strategies in recent migrants could only marginally contribute to TB elimination and are unlikely to be cost-effective unless screening costs are borne by migrants and potential LTBI treatment quality-of-life decrements are ignored.

Completion Rate and Safety of Programmatic Screening and Treatment for Latent Tuberculosis Infection in Elderly Patients With Poorly Controlled Diabetic Mellitus: A Prospective Multicenter Study

BACKGROUND

Poor control of diabetes mellitus (DM) increases active tuberculosis (TB) risk. Understanding risk factors for latent TB infection (LTBI) in this population and intervention completion rates is crucial for policy making.

METHODS

Under a collaborative multidisciplinary team consisting of public health professionals, endocrinologists, and pulmonologists, patients aged >45 years with poorly controlled DM (pDM), defined as having a glycated hemoglobin level of ≥9% within the preceding year, were enrolled by endocrinologists from 2 hospitals; these patients underwent LTBI screening by using QuantiFERON (QFT). Once-weekly isoniazid and rifapentine for 12 weeks (3HP) or daily isoniazid for 9 months (9H) was administered by pulmonologists. QFT-positivity predictors were evaluated using logistic regression. Completion rates and safety were also investigated.

RESULTS

Among 980 patients with pDM (age: 64.2 ± 9.7 years), 261 (26.6%) were QFT-positive. Age, DM duration, chronic kidney disease stage ≥3, and dipeptidyl peptidase-4 inhibitor use, not using metformin, were associated with QFT-positivity. Preventive therapy (3HP: 138; 9H: 62) was administered in 200 (76.6%) QFT-positive patients. The completion rates of 3HP and 9H were 84.1% and 79.0%, respectively (P = .494). Nine (6.5%) and zero patients in the 3HP and 9H groups, respectively, developed systemic drug reactions (P = .059); 78.3% and 45.2% had ≥1 adverse drug reactions (P < .001); and post-treatment QFT conversion rates were 32% and 20%, respectively (P = .228).

CONCLUSIONS

LTBI prevalence exceeds 25% in elderly patients with pDM. Under care from a collaborative multidisciplinary team, the completion rate of preventive therapy, regardless of regimen could approach, or even exceed 80% in this population.

Cost of Delivering 12-Dose Isoniazid and Rifapentine Versus 6 Months of Isoniazid for Tuberculosis Infection in a High-Burden Setting

BACKGROUND

Successful delivery and completion of tuberculosis preventive treatment are necessary for tuberculosis elimination. Shorter preventive treatment regimens currently have higher medication costs, but patients spend less time in care and are more likely to complete treatment. It is unknown how economic costs of successful delivery differ between longer and shorter regimens in high-tuberculosis-burden settings.

METHODS

We developed survey instruments to collect costs from program and patient sources, considering costs incurred from when household contacts first entered the health system. We compared the cost per completed course of preventive treatment with either 6 months of daily isoniazid (6H) or 3 months of weekly isoniazid and rifapentine (3HP), delivered by the Indus Health Network tuberculosis program in Karachi, Pakistan, between October 2016 and February 2018.

RESULTS

During this period, 459 individuals initiated 6H and 643 initiated 3HP; 39% and 61% completed treatment, respectively. Considering costs to both the program and care recipients, the cost per completed course was 394 US dollars (USD) for 6H and 333 USD for 3HP. Using a new 2020 price for rifapentine reduced the cost per completed course of 3HP to 290 USD. Under varying assumptions about drug prices and costs incurred by care recipients, the cost per completed course was lower for 3HP in all scenarios, and the largest cost drivers were the salaries of clinical staff.

CONCLUSIONS

In a high-burden setting, the cost of successful delivery of 3HP was lower than that of 6H, driven by higher completion.

The latent tuberculosis cascade-of-care among people living with HIV: A systematic review and meta-analysis

BACKGROUND

Tuberculosis preventive therapy (TPT) reduces TB-related morbidity and mortality in people living with HIV (PLHIV). Cascade-of-care analyses help identify gaps and barriers in care and develop targeted solutions. A previous latent tuberculosis infection (LTBI) cascade-of-care analysis showed only 18% of persons in at-risk populations complete TPT, but a similar analysis for TPT among PLHIV has not been completed. We conducted a meta-analysis to provide this evidence.

METHODS AND FINDINGS

We first screened potential articles from a LTBI cascade-of-care systematic review published in 2016. From this study, we included cohorts that reported a minimum of 25 PLHIV. To identify new cohorts, we used a similar search strategy restricted to PLHIV. The search was conducted in Medline, Embase, Health Star, and LILACS, from January 2014 to February 2021. Two authors independently screened titles and full text and assessed risk of bias using the Newcastle-Ottawa Scale for cohorts and Cochrane Risk of Bias for cluster randomized trials. We meta-analyzed the proportion of PLHIV completing each step of the LTBI cascade-of-care and estimated the cumulative proportion retained. These results were stratified based on cascades-of-care that used or did not use LTBI testing to determine eligibility for TPT. We also performed a narrative synthesis of enablers and barriers of the cascade-of-care identified at different steps of the cascade. A total of 71 cohorts were included, and 70 were meta-analyzed, comprising 94,011 PLHIV. Among the PLHIV included, 35.3% (33,139/94,011) were from the Americas and 29.2% (27,460/94,011) from Africa. Overall, 49.9% (46,903/94,011) from low- and middle-income countries, median age was 38.0 [interquartile range (IQR) 34.0;43.6], and 65.9% (46,328/70,297) were men, 43.6% (29,629/67,947) were treated with antiretroviral therapy (ART), and the median CD4 count was 390 cell/mm3 (IQR 312;458). Among the cohorts that did not use LTBI tests, the cumulative proportion of PLHIV starting and completing TPT were 40.9% (95% CI: 39.3% to 42.7%) and 33.2% (95% CI: 31.6% to 34.9%). Among cohorts that used LTBI tests, the cumulative proportions of PLHIV starting and completing TPT were 60.4% (95% CI: 58.1% to 62.6%) and 41.9% (95% CI:39.6% to 44.2%), respectively. Completion of TPT was not significantly different in high- compared to low- and middle-income countries. Regardless of LTBI test use, substantial losses in the cascade-of-care occurred before treatment initiation. The integration of HIV and TB care was considered an enabler of the cascade-of-care in multiple cohorts. Key limitations of this systematic review are the observational nature of the included studies, potential selection bias in the population selection, only 14 cohorts reported all steps of the cascade-of-care, and barriers/facilitators were not systematically reported in all cohorts.

CONCLUSIONS

Although substantial losses were seen in multiple stages of the cascade-of-care, the cumulative proportion of PLHIV completing TPT was higher than previously reported among other at-risk populations. The use of LTBI testing in PLHIV in low- and middle-income countries was associated with higher proportion of the cohorts initiating TPT and with similar rates of completion of TPT.

Cost-effectiveness analysis of 3 months of weekly rifapentine and isoniazid compared to isoniazid monotherapy in a Canadian arctic setting

OBJECTIVE

To assess the cost effectiveness of once weekly rifapentine and isoniazid for 12 weeks (3HP) to the current standard care for latent tuberculosis (TB) infection (LTBI) in Iqaluit, Nunavut.

DESIGN

A cost-effectiveness analysis using a Markov model reflecting local practices for LTBI treatment.

SETTING

A remote Canadian arctic community with a high incidence of TB.

PARTICIPANTS

Hypothetical patients with LTBI.

INTERVENTIONS

The cost effectiveness of 3HP was compared with the existing standard of care in the study region which consists of 9 months of twice weekly isoniazid (9H) given by directly observed therapy.

OUTCOME MEASURES

Effectiveness was measured in quality-adjusted life years (QALYs) with model parameters were derived from historical programmatic data, a local implementation study of 3HP and published literature. Costs from the perspective of the Nunavut healthcare system were measured in 2019 US dollars and were obtained primarily from local, empirically collected data. Secondary health outcomes included estimated TB cases and TB deaths averted using 3HP versus 9H. One way and probabilistic sensitivity analyses were performed.

RESULTS

The 3HP regimen was dominant over 9H: costs were lower (US$628 vs US$924/person) and health outcomes slightly improved (20.14 vs 20.13 QALYs/person). In comparison to 9H, 3HP treatment resulted in fewer TB cases (27.89 vs 30.16/1000 persons) and TB deaths (2.29 vs 2.48/1000 persons). 3HP completion, initiation and risk of fatal adverse events were the primary drivers of cost effectiveness.

CONCLUSION

In a remote Canadian arctic setting, using 3HP instead of 9H for LTBI treatment may result in cost savings and similar or improved health outcomes.

The paradigm shift in the approach to management of latent tuberculosis infection in high tuberculosis burden countries

Introduction: Addressing the reservoir of Latent Tuberculosis Infection (LTBI) is critical to TB elimination because if left untreated LTBI can progress to active TB disease. This additional burden can prevent achieving the global targets of TB elimination. Management of LTBI has been a low priority target for National TB Elimination Programs (NTEP) due to various challenges in the field settings.Areas covered: This article reviews the most recent advances in the field of LTBI management including newer diagnostics, treatments, vaccines, programmatic challenges, and gaps and suggests a way forward that can be adopted by NTEPs for LTBI. We searched the electronic databases of PubMed, Scopus, and Web of Science for studies published between 2010 to 2020 using MeSH terms: Latent TB Diagnosis, TB preventive therapy, Vaccines, LTBI, and HIV/ COVID.Expert opinion: NTEPs of developing countries should offer a better, point-of-care diagnostic, and effective treatment for LTBI to reduce the number of new TB cases arising from people infected with M.tb. Awareness about LTBI should be increased among the health system staff and the public. More funding is needed to advance research as well as implement the newer findings in the NTEP to achieve the End TB targets by 2035.

Health System Costs of Treating Latent Tuberculosis Infection With Four Months of Rifampin Versus Nine Months of Isoniazid in Different Settings

BACKGROUND

Four months of rifampin treatment for latent tuberculosis infection is safer, has superior treatment completion rates, and is as effective as 9 months of isoniazid. However, daily medication costs are higher for a 4-month rifampin regimen than a 9-month isoniazid regimen.

OBJECTIVE

To compare health care use and associated costs of 4 months of rifampin and 9 months of isoniazid.

DESIGN

Health system cost comparison using all health care activities recorded during 2 randomized clinical trials. (ClinicalTrials.gov: NCT00931736 and NCT00170209).

SETTING

High-income countries (Australia, Canada, Saudi Arabia, and South Korea), middle-income countries (Brazil and Indonesia), and African countries (Benin, Ghana, and Guinea).

PARTICIPANTS

Adults and children with clinical or epidemiologic factors associated with increased risk for developing tuberculosis that warranted treatment for latent tuberculosis infection.

MEASUREMENTS

Health system costs per participant.

RESULTS

A total of 6012 adults and 829 children were included. In both adults and children, greater health system use and higher costs were observed with 9 months of isoniazid than with 4 months of rifampin. In adults, the ratios of costs of 4 months of rifampin versus 9 months of isoniazid were 0.76 (95% CI, 0.70 to 0.82) in high-income countries, 0.90 (CI, 0.85 to 0.96) in middle-income countries, and 0.80 (CI, 0.78 to 0.81) in African countries. Similar findings were observed in the pediatric population.

LIMITATION

Costs may have been overestimated because the trial protocol required a minimum number of follow-up visits, although fewer than recommended by many authoritative guidelines.

CONCLUSION

A 4-month rifampin regimen was safer and less expensive than 9 months of isoniazid in all settings. This regimen could be adopted by tuberculosis programs in many countries as first-line therapy for latent tuberculosis infection.

PRIMARY FUNDING SOURCE

Canadian Institutes of Health Research.

The Growing Importance of Tuberculosis Preventive Therapy and How Research and Innovation Can Enhance Its Implementation on the Ground

Ending the tuberculosis (TB) epidemic by 2030 requires two key actions: rapid diagnosis and effective treatment of active TB and identification and treatment of latent TB infection to prevent progression to active disease. We introduce this perspective by documenting the growing importance of TB preventive therapy on the international agenda coupled with global data showing poor implementation of preventive activities in programmatic settings. We follow this with two principal objectives. The first is to examine implementation challenges around diagnosis and treatment of active TB. Within this, we include recent evidence about the continued morbidity and heightened mortality that persists after TB treatment is successfully completed, thus elevating the importance of TB preventive therapy. The second objective is to outline how current TB preventive therapy activities have been shaped and are managed and propose how these can be improved through research and innovation. This includes expanding and giving higher priority to certain high-risk groups including those with fibrotic lung lesions on chest X-ray, showcasing the need to develop and deploy new biomarkers to more accurately predict risk of disease and making shorter treatment regimens, especially with rifapentine-isoniazid, more user-friendly and widely available. Ending the TB epidemic requires not only cure of the disease but preventing it before it even begins.

Association of Drug Metabolic Enzyme Genetic Polymorphisms and Adverse Drug Reactions in Patients Receiving Rifapentine and Isoniazid Therapy for Latent Tuberculosis

Weekly rifapentine and isoniazid therapy (3HP) is the most frequent treatment for latent tuberculosis infection (LTBI). However, the association between major adverse drug reactions (ADRs) and drug metabolic enzyme single-nucleotide polymorphisms (SNPs) remains unclear. In this study, 377 participants who received the 3HP regimen were recruited and examined for genotyping of CYP5A6, CYP2B6, CYP2C19, CYP2E1, and NAT2 SNPs. In our study, 184 participants (48.4%) developed ADRs. Moreover, CYP2C19 rs4986893 (TT vs. CC+CT, odds ratio [OR] [95% CI]: 2.231 [1.015-4.906]), CYP2E1 rs2070676 (CC vs. CG+GG, OR [95% CI]: 1.563 [1.022-2.389]), and CYP2E1 rs2515641 (CC vs. CT+TT, OR [95% CI]: 1.903 [1.250-2.898]) were associated with ADR development. In conclusion, CYP2C19 and CYP2E1 SNPs may provide useful information regarding ADRs in LTBI patients receiving the 3HP regimen.

Treatment for latent tuberculosis infection in low- and middle-income countries: progress and challenges with implementation and scale-up

Introduction: Treatment of latent tuberculosis infection (LTBI) is a crucial but neglected component of global tuberculosis control. The 2018 United Nations High-Level Meeting committed world leaders to provide LTBI treatment to at least 30 million people, including 4 million children<5 years, 20 million other household contacts and 6 million HIV-infected people by 2022.Areas covered: This review searched MEDLINE between 1990 and 2019 and discussed: i) high-risk groups to be prioritized for diagnosis and treatment of LTBI; ii) challenges with diagnosing LTBI in programmatic settings; iii) LTBI treatment options including isoniazid monotherapy, shorter regimens (rifampicin-monotherapy, rifampicin-isoniazid and rifapentine-isoniazid) and treatments for contacts of drug-resistant patients; iv) issues with programmatic scale-up of treatment including policy considerations, ruling out active TB, time to start treatment, safety, uninterrupted drug supplies and treatment adherence; and v) recording and reporting.Expert opinion: In 2017, <1.5 million persons were reported to be treated for LTBI. This must rapidly increase to 6 million persons annually. If HIV programs focus on HIV-infected people already accessing or about to start antiretroviral therapy and TB programs focus on household contacts, these targets could be achieved. Isoniazid remains the current treatment of choice although shorter courses of rifapentine-isoniazid are possible alternatives.

Diagnosis and management of latent tuberculosis infection in Asia: Review of current status and challenges

Asia has the highest burden of tuberculosis (TB) and latent TB infection (LTBI) in the world. Optimizing the diagnosis and treatment of LTBI is one of the key strategies for achieving the WHO 'End TB' targets. We report the discussions from the Asia Latent TubERculosis (ALTER) expert panel meeting held in 2018 in Singapore. In this meeting, a group of 13 TB experts from Bangladesh, Cambodia, Hong Kong, India, Indonesia, Malaysia, Myanmar, the Philippines, Singapore, Taiwan, Thailand and Vietnam convened to review the literature, discuss the barriers and propose strategies to improve the management of LTBI in Asia. Strategies for the optimization of risk group prioritization, diagnosis, treatment, and research of LTBI are reported. The perspectives presented herein, may help national programs and professional societies of the respective countries enhance the adoption of the WHO guidelines, scale-up the implementation of national guidelines based on the regional needs, and provide optimal guidance to clinicians for the programmatic management of LTBI.