Chest Radiograph Screening for Detecting Subclinical Tuberculosis in Asymptomatic Household Contacts, Peru

The World Health Organization's end TB strategy promotes the use of symptom and chest radiograph screening for tuberculosis (TB) disease. However, asymptomatic early states of TB beyond latent TB infection and active disease can go unrecognized using current screening criteria. We conducted a longitudinal cohort study enrolling household contacts initially free of TB disease and followed them for the occurrence of incident TB over 1 year. Among 1,747 screened contacts, 27 (52%) of the 52 persons in whom TB subsequently developed during follow-up had a baseline abnormal radiograph. Of contacts without TB symptoms, persons with an abnormal radiograph were at higher risk for subsequent TB than persons with an unremarkable radiograph (adjusted hazard ratio 15.62 [95% CI 7.74-31.54]). In young adults, we found a strong linear relationship between radiograph severity and time to TB diagnosis. Our findings suggest chest radiograph screening can extend to detecting early TB states, thereby enabling timely intervention.

Utility of Mycobacterium tuberculosis Genome Sequencing Snapshots to Assess Transmission Dynamics Over Time

We explored the utility of brief Mycobacterium tuberculosis whole-genome sequencing (WGS) "snapshots" at a sentinel site within Lima, Peru, for evaluating local transmission dynamics over time. Within a 17-km2 area, 15 of 70 (21%) isolates with WGS collected during 2011-2012 and 22 of 81 (27%) collected during 2020-2021 were clustered (P = .414), and additional isolates clustered with those from outside the area. Isolates from the later period were disproportionately related to large historic clusters in Lima from the earlier period. WGS snapshots at a sentinel site may not be useful for monitoring transmission, but monitoring the persistence of large transmission clusters might be.

Who Transmits Tuberculosis to Whom: A Cross-Sectional Analysis of a Cohort Study in Lima, Peru

RATIONALE

The persistent burden of TB disease emphasizes the need to identify individuals with TB for treatment and those at a high risk of incident TB for prevention. Targeting interventions towards those at high risk of developing and transmitting tuberculosis is a public health priority.

OBJECTIVES

We aimed to identify characteristics of individuals involved in tuberculosis transmission in a community setting, which may guide the prioritization of targeted interventions.

METHODS

We collected clinical and socio-demographic data from a cohort of tuberculosis patients in Lima, Peru. We used whole-genome sequencing data to assess the genetic distance between all possible pairs of patients; we considered pairs to be the result of a direct transmission event if they differed by three or fewer SNPs and we assumed that the first diagnosed patient in a pair was the transmitter and the second to be the recipient. We used logistic regression to examine the association between host factors and the likelihood of direct tuberculosis transmission.

MAIN RESULTS

Analyzing data from 2,518 tuberculosis index patients, we identified 1,447 direct transmission pairs. Regardless of recipient attributes, individuals less than 34 years old, males, and those with a history of incarceration had a higher likelihood of being transmitters in direct transmission pairs. Direct transmission was more likely when both patients were drinkers or smokers.

CONCLUSIONS

This study identifies men, young adults, former prisoners, alcohol consumers, and smokers as priority groups for targeted interventions. Innovative strategies are needed to extend tuberculosis screening to social groups like young adults and prisoners with limited access to routine preventive care. This article is open access and distributed under the terms of the Creative Commons Attribution Non-Commercial No Derivatives License 4.0 (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Spatially-targeted tuberculosis screening has limited impact beyond household contact tracing in Lima, Peru: A model-based analysis

Mathematical models have suggested that spatially-targeted screening interventions for tuberculosis may efficiently accelerate disease control, but empirical data supporting these findings are limited. Previous models demonstrating substantial impacts of these interventions have typically simulated large-scale screening efforts and have not attempted to capture the spatial distribution of tuberculosis in households and communities at a high resolution. Here, we calibrate an individual-based model to the locations of case notifications in one district of Lima, Peru. We estimate the incremental efficiency and impact of a spatially-targeted interventions used in combination with household contact tracing (HHCT). Our analysis reveals that HHCT is relatively efficient with a median of 40 (Interquartile Range: 31.7 to 49.9) household contacts required to be screened to detect a single case of active tuberculosis. However, HHCT has limited population impact, producing a median incidence reduction of only 3.7% (Interquartile Range: 5.8% to 1.9%) over 5 years. In comparison, spatially targeted screening (which we modeled as active case finding within high tuberculosis prevalence areas 100 m2 grid cell) is far less efficient, requiring evaluation of ≈12 times the number of individuals as HHCT to find a single individual with active tuberculosis. Furthermore, the addition of the spatially targeted screening effort produced only modest additional reductions in tuberculosis incidence over the 5 year period (≈1.3%) in tuberculosis incidence. In summary, we found that HHCT is an efficient approach for tuberculosis case finding, but has limited population impact. Other screening approaches which target areas of high tuberculosis prevalence are less efficient, and may have limited impact unless very large numbers of individuals can be screened.

Scale-Up of Rifapentine and Isoniazid for Tuberculosis Prevention Among Household Contacts in 2 Urban Centers: An Effectiveness Assessment

BACKGROUND

Scaling up a shorter preventive regimen such as weekly isoniazid and rifapentine (3HP) for 3 months is a priority for tuberculosis (TB) preventive treatment (TPT). However, there are limited data on 3HP acceptability and completion from high-burden-TB countries.

METHODS

We scaled up 3HP from 2018 to 2021 in 2 cities in Pakistan. Eligible participants were household contacts of persons diagnosed with TB disease. Participants were prescribed 3HP after ruling out TB disease. Treatment was self-administered. We analyzed the proportion who completed 3HP.

RESULTS

In Karachi, we verbally screened 22 054 household contacts of all ages. Of these, 83% were clinically evaluated and 3% were diagnosed with TB. Of household contacts without TB disease, 59% initiated the 3HP regimen, of which 69% completed treatment. In Peshawar, we verbally screened 6389 household contacts of all ages. We evaluated 95% of household contacts, of whom 2% were diagnosed with TB disease. Among those without TB disease, 65% initiated 3HP, of which 93% completed. Factors associated with higher 3HP completion included residence in Peshawar (risk ratio [RR], 1.35 [95% confidence interval {CI}: 1.32-1.37]), index patient being a male (RR, 1.03 [95% CI: 1.01-1.05]), and index patient with extrapulmonary TB compared to bacteriologically positive pulmonary TB (RR, 1.10 [95% CI: 1.06-1.14]). The age of the index patient was inversely associated with completion.

CONCLUSIONS

We observed a high level of acceptance and completion of 3HP in programs implemented in 2 cities in Pakistan, with differences observed across the cities. These findings suggest that 3HP can be effectively scaled up in urban settings to improve the reach and impact of TPT.

Sensitivity of Various Case Detection Algorithms for Community-based Tuberculosis Screening

Using data from 388 people diagnosed with tuberculosis through a community-based screening program in Lima, Peru, we estimated that cough screening followed by sputum smear microscopy would have detected only 23% of cases found using an algorithm of radiographic screening followed by rapid nucleic acid amplification testing and clinical evaluation.

Development of a Clinical Prediction Score Including Monocyte-to-Lymphocyte Ratio to Inform Tuberculosis Treatment Among Children With HIV: A Multicountry Study

Background

Clinical pediatric tuberculosis (TB) diagnosis may lead to overdiagnosis particularly among children with human immunodeficiency virus (CHIV). We assessed the performance of monocyte-lymphocyte ratio (MLR) as a diagnostic biomarker and constructed a clinical prediction score to improve specificity of TB diagnosis in CHIV with limited access to microbiologic testing.

Methods

We pooled data from cohorts of children aged ≤13 years from Vietnam, Cameroon, and South Africa to validate the use of MLR ≥0.378, previously found as a TB diagnostic marker among CHIV. Using multivariable logistic regression, we created an internally validated prediction score for diagnosis of TB disease in CHIV.

Results

The combined cohort had 601 children (median age, 1.9 [interquartile range, 0.9-5.3] years); 300 (50%) children were male, and 283 (47%) had HIV. Elevated MLR ≥0.378 had sensitivity of 36% (95% confidence interval [CI], 23%-51%) and specificity of 79% (95% CI, 71%-86%) among CHIV in the validation cohort. A model using MLR ≥0.28, age ≥4 years, tuberculin skin testing ≥5 mm, TB contact history, fever >2 weeks, and chest radiograph suggestive of TB predicted active TB disease in CHIV with an area under the receiver operating characteristic curve of 0.85. A prediction score of ≥5 points had a sensitivity of 94% and specificity of 48% to identify confirmed TB, and a sensitivity of 82% and specificity of 48% to identify confirmed and unconfirmed TB groups combined.

Conclusions

Our score has comparable sensitivity and specificity to algorithms including microbiological testing and should enable clinicians to rapidly initiate TB treatment among CHIV when microbiological testing is unavailable.

Social Determinants of Adherence to Treatment for Tuberculosis Infection and Disease Among Children, Adolescents, and Young Adults: A Narrative Review

Global efforts to eliminate tuberculosis (TB) must address the unique barriers that children (ages 0 through 9 years) and adolescents/young adults (AYA; ages 10 through 24 years) face in adhering to treatment for TB infection and disease. We conducted a narrative review to summarize current knowledge on the social determinants of treatment adherence among these age groups to guide efforts and policy to address their unique needs. Our findings revealed that research on TB treatment adherence among children and AYA is still in its nascent stage. The current literature revealed structural/community-, health system-, household-, and individual-level factors that influence treatment adherence and varied with developmental stage. There is a need to develop multilevel interventions to address the unique challenges that children and AYA face in adhering to TB treatment.

The Contribution of Chest Radiography to the Clinical Management of Children Exposed to Tuberculosis

Rationale: Although World Health Organization guidelines emphasize contact investigation for tuberculosis (TB)-exposed children, data that support chest radiography as a useful tool are lacking. Objectives: We evaluated the diagnostic and prognostic information of chest radiography in children exposed to TB and measured the efficacy of isoniazid preventive therapy (IPT) in those with relevant radiographic abnormalities. Methods: Between September 2009 and August 2012, we enrolled 4,468 TB-exposed children who were screened by tuberculin skin testing, symptom assessment, and chest radiography. Those negative for TB disease were followed for 1 year for the occurrence of new TB diagnoses. We assessed the protective efficacy of IPT in children with and without abnormal chest radiographs. Measurements and Main Results: Compared with asymptomatic children with normal chest films, asymptomatic children with abnormal radiographs were 25.1-fold more likely to have coprevalent TB (95% confidence interval [CI], 1.02-613.76) and 26.7-fold more likely to be diagnosed with incident TB disease during follow-up (95% CI, 10.44-68.30). Among the 29 symptom-negative and CXR-abnormal child contacts, 20% (3/15) of the isoniazid recipients developed incident TB, compared with 57% (8/14) of those who did not receive IPT (82% IPT efficacy). Conclusions: Our results strongly support the use of chest radiography as a routine screening tool for the evaluation of child TB contacts, which is readily available. Radiographic abnormalities not usually considered suggestive of TB may indicate incipient or subclinical disease, although TB preventive treatment is adequate in most cases.

Age-specific Clinical Presentation and Risk Factors for Extrapulmonary Tuberculosis Disease in Children

BACKGROUND

Clinical presentation for extrapulmonary tuberculosis (EPTB) in children can be variable and nonspecific, leading to delayed diagnosis, disease and death. We describe the age-specific clinical presentation and identify risk factors for EPTB among children in Pakistan.

METHODS

In 2015-2016 in 4 facilities in Sindh, Pakistan, children were diagnosed with TB either through bacteriologic confirmation or clinical-radiologic criteria. EPTB comprised any form of TB disease that did not involve the lungs. Among children with TB disease, we report demographics, clinical characteristics and symptoms, family medical history and diagnostic test results for children with and without EPTB. We conduct age-specific regression analyses to identify factors associated with an EPTB diagnosis among children age 0-4, 5-9 and 10-14 years.

RESULTS

A total of 1163 children were diagnosed with TB disease, of which 157 (13.5%) had EPTB. Of those, 46 (29.3%) were 0-4, 53 (33.8%) were 5-9 and 58 (36.9%) were 10-14 years old. Of children with EPTB, the most frequently reported sites were lymph node (113, 72.4%) and abdominal (31, 19.9%). Weight loss was associated with an increased risk of EPTB in the 0-4-year-old (adjusted odds ratio: 2.80, 95% confidence interval: 1.05-7.47) and 10-14-year-old (adjusted odds ratio: 2.79, 95% confidence interval: 1.28-6.07) groups, and the presence of cough was associated with a decreased risk of EPTB.

CONCLUSIONS

This study provides new knowledge about age-specific clinical presentation and risk factors of EPTB in children in Pakistan. Our results can help to optimize clinical algorithms designed to achieve a timely diagnosis in children with EPTB along with improved treatment outcomes.

Treatment Outcomes Among Pregnant Patients With Multidrug-Resistant Tuberculosis: A Systematic Review and Meta-analysis

IMPORTANCE

The management of multidrug-resistant tuberculosis (MDR-TB) during pregnancy is challenging, yet no systematic synthesis of evidence has accurately measured treatment outcomes.

OBJECTIVE

To systematically synthesize treatment outcomes and adverse events among pregnant patients with MDR-TB.

DATA SOURCES

PubMed, Scopus, Web of Science, and ProQuest were searched from the inception of each database through August 31, 2021.

STUDY SELECTION

Studies containing cohorts of pregnant patients with a defined treatment outcome were eligible.

DATA EXTRACTION AND SYNTHESIS

Independent reviewers screened studies and assessed the risk of bias. The study followed the Preferring Reporting Items for Systematic Review and Meta-analyses reporting guideline. Meta-analysis was performed using random-effects models. The sources of heterogeneity were explored through metaregression.

MAIN OUTCOMES AND MEASURES

The primary outcome was the proportion of patients with each treatment outcome (including treatment success, death, loss to follow-up, and treatment failure), and the secondary outcomes included the proportion of patients experiencing adverse events during pregnancy.

RESULTS

In this systematic review and meta-analysis, 10 studies containing 275 pregnant patients with available data on treatment outcomes were included. The pooled estimate was 72.5% (95% CI, 63.3%-81.0%) for treatment success, 6.8% (95% CI, 2.6%-12.4%) for death, 18.4% (95% CI, 13.1%-24.2%) for loss to follow-up, and 0.6% (95% CI, 0.0%-2.9%) for treatment failure. Treatment success was significantly higher in studies in which the proportion of patients taking linezolid was greater than the median (20.1%) compared with studies in which this proportion was lower than the median (odds ratio, 1.22; 95% CI, 1.05-1.42). More than half of the pregnant patients (54.7%; 95% CI, 43.5%-65.4%) experienced at least 1 type of adverse event, most commonly liver function impairment (30.4%; 95% CI, 17.7%-45.7%), kidney function impairment (14.9%; 95% CI, 6.2%-28.3%), hypokalemia (11.9%; 95% CI, 3.9%-25.6%), hearing loss (11.8%; 95% CI, 5.5%-21.3%), gastrointestinal disorders (11.8%; 95% CI, 5.2%-21.8%), psychiatric disorders (9.1%; 95% CI, 2.5%-21.6%), or anemia (8.9%; 95% CI, 3.6%-17.4%). The pooled proportion of favorable pregnancy outcomes was 73.2% (95% CI, 49.4%-92.1%). The most common types of adverse pregnancy outcomes were preterm birth (9.5%; 95% CI, 0.0%-29.0%), pregnancy loss (6.0%; 95% CI, 1.3%-12.9%), low birth weight (3.9%; 95% CI, 0.0%-18.7%), and stillbirth (1.9%; 95% CI, 0.1%-5.1%). Most of the studies had low-quality (3 studies) or medium-quality (4 studies) scores.

CONCLUSIONS AND RELEVANCE

In this systematic review and meta-analysis, high treatment success and favorable pregnancy outcomes were reported among pregnant patients with MDR-TB. Further research is needed to design shorter, more effective, and safer treatment regimens for pregnant patients with MDR-TB.

Pediatric Tuberculosis Research and Development: Progress, Priorities and Funding Opportunities

In this article, we highlight technological pediatric TB research advances across the TB care cascade; discuss recently completed or ongoing work in adults and corresponding significant research gaps for children; and offer recommendations and opportunities to increase investments and accelerate pediatric TB R&D.

A role for community-level socioeconomic indicators in targeting tuberculosis screening interventions

Tuberculosis screening programs commonly target areas with high case notification rates. However, this may exacerbate disparities by excluding areas that already face barriers to accessing diagnostic services. We compared historic case notification rates, demographic, and socioeconomic indicators as predictors of neighborhood-level tuberculosis screening yield during a mobile screening program in 74 neighborhoods in Lima, Peru. We used logistic regression and Classification and Regression Tree (CART) analysis to identify predictors of screening yield. During February 7, 2019-February 6, 2020, the program screened 29,619 people and diagnosed 147 tuberculosis cases. Historic case notification rate was not associated with screening yield in any analysis. In regression analysis, screening yield decreased as the percent of vehicle ownership increased (odds ratio [OR]: 0.76 per 10% increase in vehicle ownership; 95% confidence interval [CI]: 0.58-0.99). CART analysis identified the percent of blender ownership (≤ 83.1% vs > 83.1%; OR: 1.7; 95% CI: 1.2-2.6) and the percent of TB patients with a prior tuberculosis episode (> 10.6% vs ≤ 10.6%; OR: 3.6; 95% CI: 1.0-12.7) as optimal predictors of screening yield. Overall, socioeconomic indicators were better predictors of tuberculosis screening yield than historic case notification rates. Considering community-level socioeconomic characteristics could help identify high-yield locations for screening interventions.

Prediction Tool to Identify Children at Highest Risk of Tuberculosis Disease Progression Among Those Exposed at Home

BACKGROUND

There is a dearth of research to understand which children, among those who are exposed at home to tuberculosis (TB), are at the highest risk of TB disease, to tailor care. We sought to identify predictors of TB progression in children.

METHODS

We conducted a prospective cohort study of children living with adults with pulmonary TB in Lima, Peru (2009-2012). We applied classification and regression tree analysis to examine potential predictors of incident TB disease during 12 months in 3 age groups (0-4, 5-9, and 10-14 years). We calculated the relative risk (RR) for top predictors in each age group.

RESULTS

Among 4545 children 0-14 years old, 156 (3.4%) were diagnosed with TB within 1 year of household exposure to TB (3.4%, 2.3%, and 4.7% in children 0-4, 5-9, and 10-14 years old, respectively). The most important predictor of TB was having a positive tuberculin skin test (TST) result, with RRs of 6.6 (95% CI, 4.0-10.7), 6.6 (95% CI, 3.2-13.6), and 5.2 (95% CI, 3.0-9.0) in the age groups 0-4, 5-9, and 10-14 years, respectively. In young children with a positive TST, not using isoniazid preventive treatment further increased risk of disease (RR, 12.2 [95% CI, 3.8-39.2]).

CONCLUSIONS

We present a tool that identifies child household contacts at high risk of TB disease progression based on data collected during contact tracing. In addition to the use of TB preventive therapy for all children exposed at home to TB, those children at highest risk of progressing to TB disease may benefit from more frequent follow-up.

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.

Concordance of Drug-resistance Profiles Between Persons With Drug-resistant Tuberculosis and Their Household Contacts: A Systematic Review and Meta-analysis

BACKGROUND

Household contacts of patients with drug-resistant tuberculosis (TB) are at high risk for being infected with Mycobacterium tuberculosis and for developing TB disease. To guide regimen composition for the empirical treatment of TB infection and disease in these household contacts, we estimated drug-resistance profile concordance between index patients with drug-resistant TB and their household contacts.

METHODS

We performed a systematic review and meta-analysis of studies published through 24 July 2018 that reported resistance profiles of drug-resistant TB index cases and secondary cases within their households. Using a random-effects meta-analysis, we estimated resistance profile concordance, defined as the percentage of secondary cases whose M. tuberculosis strains were resistant to the same drugs as strains from their index cases. We also estimated isoniazid/rifampin concordance, defined as whether index and secondary cases had identical susceptibilities for isoniazid and rifampin only.

RESULTS

We identified 33 eligible studies that evaluated resistance profile concordance between 484 secondary cases and their household index cases. Pooled resistance profile concordance was 54.3% (95% confidence interval [CI], 40.7-67.6%; I2 = 85%). Pooled isoniazid/rifampin concordance was 82.6% (95% CI, 72.3-90.9%; I2 = 73%). Concordance estimates were similar in a subanalysis of 16 studies from high-TB-burden countries. There were insufficient data to perform a subanalysis among pediatric secondary cases.

CONCLUSIONS

Household contacts of patients with drug-resistant TB should receive treatment for TB infection and disease that assumes that they, too, are infected with a drug-resistant M. tuberculosis strain. Whenever possible, drug susceptibility testing should be performed for secondary cases to optimize regimen composition.

Identifying barriers and facilitators to implementation of community-based tuberculosis active case finding with mobile X-ray units in Lima, Peru: a RE-AIM evaluation

OBJECTIVES

Identify barriers and facilitators to integrating community tuberculosis screening with mobile X-ray units into a health system.

METHODS

Reach, effectiveness, adoption, implementation and maintenance evaluation.

SETTING

3-district region of Lima, Peru.

PARTICIPANTS

63 899 people attended the mobile units from 7 February 2019 to 6 February 2020.

INTERVENTIONS

Participants were screened by chest radiography, which was scored for abnormality by computer-aided detection. People with abnormal X-rays were evaluated clinically and by GeneXpert MTB/RIF (Xpert) sputum testing. People diagnosed with tuberculosis at the mobile unit were accompanied to health facilities for treatment initiation.

PRIMARY AND SECONDARY OUTCOME MEASURES

Reach was defined as the percentage of the population of the three-district region that attended the mobile units. Effectiveness was defined as the change in tuberculosis case notifications over a historical baseline. Key implementation fidelity indicators were the percentages of people who had chest radiography performed, were evaluated clinically, had sputum samples collected, had valid Xpert results and initiated treatment.

RESULTS

The intervention reached 6% of the target population and was associated with an 11% (95% CI 6 to 16) increase in quarterly case notifications, adjusting for the increasing trend in notifications over the previous 3 years. Implementation indicators for screening, sputum collection and Xpert testing procedures all exceeded 85%. Only 82% of people diagnosed with tuberculosis at the mobile units received treatment; people with negative or trace Xpert results were less likely to receive treatment. Suboptimal treatment initiation was driven by health facility doctors' lack of familiarity with Xpert and lack of confidence in diagnoses made at the mobile unit.

CONCLUSION

Mobile X-ray units were a feasible and effective strategy to extend tuberculosis diagnostic services into communities and improve early case detection. Effective deployment however requires advance coordination among stakeholders and targeted provider training to ensure that people diagnosed with tuberculosis by new modalities receive prompt treatment.

Effectiveness of Preventive Therapy for Persons Exposed at Home to Drug-Resistant Tuberculosis, Karachi, Pakistan

Fluoroquinolone-based preventive therapy reduced risk for tuberculosis disease by 65%.

In Karachi, Pakistan, a South Asian megacity with a high prevalence of tuberculosis (TB) and low HIV prevalence, we assessed the effectiveness of fluoroquinolone-based preventive therapy for drug-resistant (DR) TB exposure. During February 2016–March 2017, high-risk household contacts of DR TB patients began a 6-month course of preventive therapy with a fluoroquinolone-based, 2-drug regimen. We assessed effectiveness in this cohort by comparing the rate and risk for TB disease over 2 years to the rates and risks reported in the literature. Of 172 participants, TB occurred in 2 persons over 336 person-years of observation. TB disease incidence rate observed in the cohort was 6.0/1,000 person-years. The incidence rate ratio ranged from 0.29 (95% CI 0.04–1.3) to 0.50 (95% CI 0.06–2.8), with a pooled estimate of 0.35 (95% CI 0.14–0.87). Overall, fluoroquinolone-based preventive therapy for DR TB exposure reduced risk for TB disease by 65%.

Smoking cessation in tuberculosis patients and the risk of tuberculosis infection in child household contacts

BACKGROUND

While previous studies have shown that cigarette smoking increases the infectiousness of tuberculosis patients, the impact of smoking cessation on tuberculosis transmissibility has not been evaluated.

DESIGN/METHODS

Between 2009 and 2012, we enrolled 4,500 tuberculosis patients and followed 14,044 household contacts in Lima, Peru. Tuberculosis patients were classified into four categories: never smoked, quit in the distant past (stopped smoking >2 months prior to time of diagnosis), recently quit (stopped smoking ≤2 months prior to time of diagnosis), and active smokers. We used a modified Poisson generalized estimating equation to assess the risk of tuberculosis infection of child contacts at enrollment and by six months of follow-up.

RESULTS

In total, 1,371 (76.8%) child contacts were exposed to patients who had never smoked, 211 (11.8%) were exposed to distant quitters, 155 (8.7%) were exposed to recent quitters, and 49 (2.7%) were exposed to active smokers. Compared to child contacts of index patients who had never smoked, child contacts of recent quitters had a similar risk of tuberculosis infection at enrollment (adjusted risk ratio [aRR], 0.81, 95% CI, 0.50-1.32) and by six months of follow-up (aRR, 0.76, 95% CI, 0.51-1.13); child contacts of recent quitters had a significantly reduced risk of tuberculosis infection compared to contacts of active smokers (enrollment aRR, 0.45, 95% CI, 0.24-0.87; 6-month follow-up aRR, 0.48, 95% CI, 0.29-0.79).

CONCLUSIONS

Our results show that the adverse effects of smoking on the transmissibility of tuberculosis are significantly reduced shortly after quitting smoking, reinforcing the importance of smoking cessation interventions in tuberculosis control.

Risk Factors for Adverse Events in Household Contacts Prescribed Preventive Treatment for Drug-resistant Tuberculosis Exposure

BACKGROUND

Completion of tuberculosis (TB) preventive treatment is important to optimize efficacy; treatment-related adverse events (AEs) sometimes result in discontinuation. This study describes the occurrence of AEs and their risk factors during a 6-month, 2-drug, fluoroquinolone-based preventive treatment for household contacts of patients with drug-resistant TB in Karachi, Pakistan.

METHODS

The primary outcome was development of any clinical AE during preventive treatment. Adverse events were categorized using the AE grading tables of the National Institutes of Health. Time-to-event analysis with Kaplan-Meier curves and Cox proportional hazards models accounting for recurrence were used to analyze associated risk factors.

RESULTS

Of the 172 household contacts on preventive treatment, 36 (21%) developed 64 AEs during 813 months of treatment. The incidence of AEs over 6 months of treatment was 7.9 per 100 person-months; 16 per 100 person-months with a fluoroquinolone and ethionamide, and 4.4 per 100 person-months with a fluoroquinolone and ethambutol. There were 53 (83%) grade 1 and 11 grade 2 AEs, with no grade 3 or 4 AEs. In multivariable analysis, the risk of AEs was higher in contacts prescribed ethionamide as compared to ethambutol adjusting for age, sex, and body mass index (adjusted hazard ratio, 2.1 [95% confidence interval {CI}, 1.2-3.6]). Overall, there was no notable difference in treatment completion among the contacts who experienced an AE and those who did not (crude odds ratio, 1.1 [95% CI, .52-2.5]).

CONCLUSIONS

A fluoroquinolone-based preventive treatment regimen for drug-resistant TB exposure is well tolerated. Regimens with ethionamide are more likely to result in AEs.

Safety and feasibility of 1 month of daily rifapentine plus isoniazid to prevent tuberculosis in children and adolescents: a prospective cohort study

BACKGROUND

Shorter regimens for tuberculosis prevention can improve completion rates and protection against developing active tuberculosis disease after tuberculosis exposure. We aimed to assess the safety and feasibility of 1 month of daily isoniazid and rifapentine (1HP) in children and adolescents in a low-resource setting in south Asia with low prevalence of HIV.

METHODS

This prospective cohort study was done in eight tuberculosis facilities in Karachi, Pakistan. Eligible participants were aged 2-19 years and were household contacts of patients with drug-susceptible tuberculosis infection. After clinical, radiological, and laboratory evaluation to rule out tuberculosis disease, participants were prescribed 1HP as a preventive regimen. Isoniazid was administered as 100 mg or 300 mg oral tablets and rifapentine was administered as 150 mg oral tablets. Dosing was according to participant bodyweight. The primary endpoints were the cumulative probability of a household contact completing all stages of the preventive care cascade, assessed in all eligible participants, and the proportion of household contacts completing 1HP, assessed among all those who initiated the regimen. Safety was assessed in all household contacts who initiated the 1HP regimen.

FINDINGS

Between Dec 21, 2019, and March 20, 2020, 1395 household contacts of 253 patients with tuberculosis were identified, including 678 household contacts who were eligible to participate. 628 (93%) completed evaluation, of whom ten (2%) had active tuberculosis disease. Of the 618 individuals eligible for tuberculosis prevention, 408 (66%) initiated 1HP, 385 (94%) of whom completed the regimen. The median duration of 1HP was 31 days (IQR 30-32) in those who completed the regimen. The cumulative probability of completing all steps of the tuberculosis prevention cascade was 58%. A girl aged 11 years developed tuberculosis disease within 6 months of completing 1HP. A boy aged 14 years developed a burning sensation during 1HP therapy and discontinued the regimen. No other adverse events were observed.

INTERPRETATION

1HP can be safely and feasibly implemented as tuberculosis prevention in children and adolescents in programmatic settings.

FUNDING

The Global Fund to Fight AIDS, Tuberculosis and Malaria.

Mycobacterium tuberculosis Beijing Lineage and Risk for Tuberculosis in Child Household Contacts, Peru

Few studies have prospectively compared the relative transmissibility and propensity to cause disease of Mycobacterium tuberculosis Beijing strains with other human-adapted strains of the M. tuberculosis complex. We assessed the effect of Beijing strains on the risk for M. tuberculosis infection and disease progression in 9,151 household contacts of 2,223 culture-positive pulmonary tuberculosis (TB) patients in Lima, Peru. Child contacts exposed to Beijing strains were more likely than child contacts exposed to non-Beijing strains to be infected at baseline, by 12 months of follow-up, and during follow-up. We noted an increased but nonsignificant tendency for child contacts to develop TB. Beijing strains were not associated with TB in adult contacts. These findings suggest that Beijing strains are more transmissible in children than are non-Beijing strains.

Closing delivery gaps in the treatment of tuberculosis infection: Lessons from implementation research in Peru

Background

Targeted testing and treatment of TB infection to prevent disease is a pillar of TB elimination. Despite recent global commitments to greatly expand access to preventive treatment for TB infection, there remains a lack of research on how best to expand preventive treatment programs in settings with high TB burdens.

Methods

We conducted implementation research in Lima, Peru, around a multifaceted intervention to deliver TB preventive treatment to close contacts of all ages, health care workers, and people in congregate settings. Key interventions included use of the interferon gamma release assay (IGRA), specialist support for generalist physicians at primary-level health facilities, and treatment support by community health workers. We applied a convergent mixed methods approach to evaluate feasibility and acceptability based on a care cascade framework.

Findings

During April 2019-January 2020, we enrolled 1,002 household contacts, 148 non-household contacts, 107 residents and staff of congregate settings, and 357 health care workers. Cumulative completion of the TB preventive care cascade was 34% for contacts <5 years old, 28% for contacts 5–19 years old, 18% for contacts ≥20 years old, 0% for people in congregate settings, and 4% of health care workers. IGRA testing was acceptable to adults exposed to TB. Preventive treatment was acceptable to contacts, but less acceptable to physicians, who frequently had doubts about prescribing preventive treatment for adults. Community-based treatment support was both acceptable and feasible, and periodic home-visits or calls were identified as facilitators of adherence.

Conclusions

We attempted to close the gap in TB preventive treatment in Peru by expanding preventive services to adult contacts and other risk groups. While suboptimal, care cascade completion for adult contacts was consistent with what has been observed in high-income settings. The major losses in the care cascade occurred in completing evaluations and having doctors prescribe preventive treatment.

Predictors of unsuccessful tuberculosis treatment outcomes in children from a prospective cohort study in Pakistan

Background

Every year, about 239 000 children die from tuberculosis (TB), despite availability of highly effective regimens. Few studies have evaluated predictors for poor treatment outcomes in children treated for TB.

Methods

We assessed predictors of unsuccessful TB treatment outcomes in a prospective cohort of children diagnosed by an intensified TB patient-finding intervention at four facilities in Pakistan between 2014 and 2016. A case of TB disease was determined through either bacteriologic confirmation of disease or a clinical diagnosis. To estimate characteristics predictive of experiencing an unsuccessful treatment outcome, we used a multi-level model with a modified Poisson approach, accounting for clustering at the facility level. We report estimated relative risks (RR) and 95% confidence intervals (CI).

Results

During the study period, 1404 children less than 15 years old were initiated on treatment for drug-susceptible TB. In total, 709 (50.5%) were 0-4, 406 (28.9%) were 5-9 years, and 289 (20.6%) were 10-14 years old; 614 (43.7%) were female; and of the 1377 children assessed for malnourishment, 1161 (84.3%) were malnourished. A total of 1322 (94.2%) children experienced a successful treatment outcome, 14 (1.0%) children transferred out to a different facility, and 68 (4.8%) children experienced an unsuccessful treatment outcome: 14 (1.0%) died, 20 (1.4%) failed treatment, and 34 (2.4%) were lost to follow-up. After adjustment for age group, sex, and malnutrition status, we identified increased risk of unsuccessful treatment outcome in children presenting with fever (RR = 2.56, 95% CI = 1.02-6.44; P = 0.05) or an abdominal examination suggestive of TB disease (RR = 2.34, 95% CI = 1.20-4.58; P = 0.01), and a decreased risk in children who initiated treatment at a rural facility (RR = 0.05, 95% CI = 0.00-0.74; P = 0.03).

Conclusions

More than 94% of children experienced successful treatment outcomes. We identified individual-, facility-, and clinical-factors predictive of experiencing unsuccessful treatment outcomes. Children with fevers and abdominal findings suggestive of TB disease should be tested for TB and followed closely throughout treatment to ensure necessary support for successful completion of treatment.

Toward patient-centered tuberculosis preventive treatment: preferences for regimens and formulations in Lima, Peru

BACKGROUND

To ensure patient-centered tuberculosis preventive treatment, it is important to consider factors that make it easier for patients to complete treatment. However, there is little published literature about patient preferences for different preventive treatment regimen options, particularly from countries with high tuberculosis burdens.

METHODS

We conducted a qualitative research study using a framework analysis approach to understand tuberculosis preventive treatment preferences among household contacts. We conducted three focus group discussions with 16 members of families affected by tuberculosis in Lima, Peru. Participants were asked to vote for preferred preventive treatment regimens and discuss the reasons behind their choices. Coding followed a deductive approach based on prior research, with data-driven codes added.

RESULTS

In total, 7 (44%) participants voted for 3 months isoniazid and rifapentine, 4 (25%) chose 3 months isoniazid and rifampicin, 3 (19%) chose 4 months rifampicin, and 2 (13%) chose 6 months isoniazid. Preferences for shorter regimens over 6 months of isoniazid were driven by concerns over "getting tired" or "getting bored" of taking medications, the difficulty of remembering to take medications, side effects, and interference with daily life. For some, weekly dosing was perceived as being easier to remember and less disruptive, leading to a preference for 3 months isoniazid and rifapentine, which is dosed weekly. However, among caregivers, having a child-friendly formulation was more important than regimen duration. Caregivers reported difficulty in administering pills to children, and preferred treatments available as syrup or dispersible formulations.

CONCLUSIONS

There is demand for shorter regimens and child-friendly formulations for tuberculosis preventive treatment in high-burden settings. Individual preferences differ, suggesting that patient-centered care would best be supported by having multiple shorter regimens available.

Tuberculosis Preventive Therapy for Individuals Exposed to Drug-resistant Tuberculosis: Feasibility and Safety of a Community-based Delivery of Fluoroquinolone-containing Preventive Regimen

BACKGROUND

Observational studies have demonstrated the effectiveness of a fluoroquinolone-based regimen to treat individuals presumed to be infected with drug-resistant tuberculosis (DR-TB). We sought to assess the feasibility of this approach in an urban setting in South Asia.

METHODS

From February 2016 until March 2017, all household contacts of DR-TB patients enrolled at the Indus Hospital were screened for TB symptoms at home. Children aged 0-17 years, symptomatic adults, and those with an immunocompromising condition (human immunodeficiency virus, diabetes, or malnutrition) were evaluated for TB disease. Contacts diagnosed with TB disease were started on treatment. Contacts without TB disease aged <5 years, contacts aged between 5 and 17 years with either a positive tuberculin skin test or an immunocompromising condition, or contacts aged ≥18 years with an immunocompromising condition were offered 6 months of treatment with a fluoroquinolone.

RESULTS

One hundred households with 800 contacts were enrolled: 353 (44.1%) individuals aged ≤17 years with a median age of 19 years (interquartile range, 10-32); 423 (52.9%) were males. In total, 737 (92.1%) individuals were screened, of which 8 were already on treatment for TB (1.1%); another 3 (0.4%) contacts were diagnosed with TB disease and started on treatment. Of 215 eligible for infection treatment, 172 (80.0%) contacts initiated and 121 (70.3%) completed treatment. No TB disease or significant adverse events were observed during 12 months of follow-up.

CONCLUSIONS

Fluoroquinolone-based treatment for contacts with presumed DR-TB infection is feasible and well tolerated in a high TB burden setting.

Two Clinical Prediction Tools to Improve Tuberculosis Contact Investigation

BACKGROUND

Efficient contact investigation strategies are needed for the early diagnosis of tuberculosis (TB) disease and treatment of latent TB infections.

METHODS

Between September 2009 and August 2012, we conducted a prospective cohort study in Lima, Peru, in which we enrolled and followed 14 044 household contacts of adults with pulmonary TB. We used information from a subset of this cohort to derive 2 clinical prediction tools that identify contacts of TB patients at elevated risk of progressing to active disease by training multivariable models that predict (1) coprevalent TB among all household contacts and (2) 1-year incident TB among adult contacts. We validated the models in a geographically distinct subcohort and compared the relative utilities of clinical decisions based on these tools to existing strategies.

RESULTS

In our cohort, 296 (2.1%) household contacts had coprevalent TB and 145 (1.9%) adult contacts developed incident TB within 1 year of index patient diagnosis. We predicted coprevalent disease using information that could be readily obtained at the time an index patient was diagnosed and predicted 1-year incident TB by including additional contact-specific characteristics. The area under the receiver operating characteristic curves for coprevalent TB and incident TB were 0.86 (95% confidence interval [CI], .83-.89]) and 0.72 (95% CI, .67-.77), respectively. These clinical tools give 5%-10% higher relative utilities than existing methods.

CONCLUSIONS

We present 2 tools that identify household contacts at high risk for TB disease based on reportable information from patient and contacts alone. The performance of these tools is comparable to biomarkers that are both more costly and less feasible than this approach.

Isoniazid Preventive Therapy in Contacts of Multidrug-Resistant Tuberculosis

Rationale: The World Health Organization recommends the use of isoniazid (INH) alone or in combination with rifapentine to treat latent tuberculosis infections. The recent rise of drug-resistant tuberculosis has complicated the choice of treatment regimen for latent tuberculosis infection.Objectives: To evaluate the effects of INH preventive therapy on the contacts of patients with multidrug-resistant tuberculosis.Methods: In a prospective cohort study conducted between September 2009 and August 2012, we identified 4,500 index patients with tuberculosis and 14,044 tuberculosis-exposed household contacts who we followed for 1 year for the occurrence of incident tuberculosis disease. Although Peruvian national guidelines specify that INH preventive therapy should be provided to contacts aged 19 years old or younger, only half this group received INH preventive therapy.Measurements and Main Results: Among 4,216 contacts under 19 years of age, 2,106 contacts (50%) initiated INH preventive therapy at enrollment. The protective effect of INH was more extreme in contacts exposed to drug-sensitive tuberculosis (adjusted hazard ratio, 0.30; 95% confidence interval, 0.18-0.48) and to multidrug-resistant tuberculosis (adjusted hazard ratio, 0.19; 95% confidence interval, 0.05-0.66) compared with those exposed to mono-INH-resistant tuberculosis (adjusted hazard ratio, 0.80; 95% confidence interval, 0.23-2.80). In the second independent study, tuberculosis occurred in none of the 76 household contacts who received INH preventive therapy compared with 3% (8 of 273) of those who did not.Conclusions: Household contacts who received INH preventive therapy had a lower incidence of tuberculosis disease even when they had been exposed to an index patient with multidrug-resistant tuberculosis. INH may have a role in the management of latent multidrug-resistant tuberculosis infection.

Tuberculosis clinical presentation and treatment outcomes in pregnancy: a prospective cohort study

BACKGROUND

There is limited research to guide TB treatment specifically in pregnant women and few studies have described the presentation of TB in pregnant women. We aimed to understand TB presentation and treatment outcomes in pregnant women in a low HIV burden setting. We describe a cohort of women of childbearing age treated for TB disease in Lima, Peru, and compare clinical presentation and treatment outcomes among pregnant and non-pregnant women between 2009 and 2012, including 36 pregnant women.

METHODS

This is a prospective cohort study. Subjects were recruited from across 106 public health centers in Lima, Peru. Baseline demographic, medical history, and drug-susceptibility test results were collected. We used descriptive statistics to describe demographic and clinical characteristics of the women using Pearson chi-squared, Fisher's exact tests, or Kruskal-Wallis.

RESULTS

Among 4500 individuals with pulmonary TB disease, 1334 women were included in analysis with 36 (2.69%) pregnant women. Pregnant women had similar demographics, past medical histories, and clinical presentation to non-pregnant women, except being more likely to be married (p = 0.01) and have cardiac disease (p = 0.04) and less likely to have weight loss (p = 0.05). Twenty (71.4%) pregnant women had pan-susceptible TB compared with 616 (63.1%) non-pregnant women; four (14.3%) pregnant women had mono-resistant TB compared with 154 (15.8%) non-pregnant women; and four (14.3%) pregnant women had multi-drug-resistant TB compared with 140 (14.3%) of non-pregnant women (p = 0.53). Twenty-eight (96.6%) pregnant women had a successful outcome (cure, completed treatment, treatment ended early by clinical team) while one (3.4%) had an unsuccessful outcome (treatment failed) and 1074 (97.3%) non-pregnant women had a successful outcome while 30 (2.7%) had an unsuccessful outcome (p = 0.56).

CONCLUSION

In this cohort with low HIV co-infection, we found high TB treatment success rates in both pregnant and non-pregnant women, irrespective of drug-susceptibility profiles. If treated appropriately, pregnant women with TB disease can have successful outcomes.

Children as sentinels of tuberculosis transmission: disease mapping of programmatic data

BACKGROUND

Identifying hotspots of tuberculosis transmission can inform spatially targeted active case-finding interventions. While national tuberculosis programs maintain notification registers which represent a potential source of data to investigate transmission patterns, high local tuberculosis incidence may not provide a reliable signal for transmission because the population distribution of covariates affecting susceptibility and disease progression may confound the relationship between tuberculosis incidence and transmission. Child cases of tuberculosis and other endemic infectious disease have been observed to provide a signal of their transmission intensity. We assessed whether local overrepresentation of child cases in tuberculosis notification data corresponds to areas where recent transmission events are concentrated.

METHODS

We visualized spatial clustering of children < 5 years old notified to Peru's National Tuberculosis Program from two districts of Lima, Peru, from 2005 to 2007 using a log-Gaussian Cox process to model the intensity of the point-referenced child cases. To identify where clustering of child cases was more extreme than expected by chance alone, we mapped all cases from the notification data onto a grid and used a hierarchical Bayesian spatial model to identify grid cells where the proportion of cases among children < 5 years old is greater than expected. Modeling the proportion of child cases allowed us to use the spatial distribution of adult cases to control for unobserved factors that may explain the spatial variability in the distribution of child cases. We compare where young children are overrepresented in case notification data to areas identified as transmission hotspots using molecular epidemiological methods during a prospective study of tuberculosis transmission conducted from 2009 to 2012 in the same setting.

RESULTS

Areas in which childhood tuberculosis cases are overrepresented align with areas of spatial concentration of transmission revealed by molecular epidemiologic methods.

CONCLUSIONS

Age-disaggregated notification data can be used to identify hotspots of tuberculosis transmission and suggest local force of infection, providing an easily accessible source of data to target active case-finding intervention.

Using Changes in Weight-for-Age z Score to Predict Effectiveness of Childhood Tuberculosis Therapy

BACKGROUND

International guidelines recommend monitoring weight as an indicator of therapeutic response in childhood tuberculosis (TB) disease. This recommendation is based on observations in adults. In the current study, we evaluated the association between weight change and treatment outcome, the accuracy of using weight change to predict regimen efficacy, and whether successfully treated children achieve catch-up weight gain.

METHODS

We enrolled children treated for drug-susceptible TB disease (group 1) and multidrug-resistant TB disease (group 2) in Peru. We calculated the change in weight-for-age z score (ΔWAZ) between baseline and the end of treatment months 2-5 for group 1, and between baseline and months 2-8 for group 2. We used logistic regression and generalized estimating equation models to evaluate the relationship between ΔWAZ and outcome. We plotted receiver operating characteristic curves to determine the accuracy of ΔWAZ for predicting treatment failure or death.

RESULTS

Groups 1 and 2 included 100 and 94 children, respectively. In logistic regression, lower ΔWAZ in months 3-5 and month 7 was associated with treatment failure or death in groups 1 and 2, respectively. In generalized estimating equation models, children in both groups who experienced treatment failure or death had lower ΔWAZ than successfully treated children. The ΔWAZ predicted treatment failure or death with 60%-90% sensitivity and 60%-86% specificity in months 2-5 for group 1 and months 7-8 for group 2. All successfully treated children-except group 2 participants with unknown microbiologic confirmation status-achieved catch-up weight gain.

CONCLUSIONS

Weight change early in therapy can predict the outcome of childhood TB treatment.

Transmissibility and potential for disease progression of drug resistant Mycobacterium tuberculosis: prospective cohort study

OBJECTIVE

To measure the association between phenotypic drug resistance and the risk of tuberculosis infection and disease among household contacts of patients with pulmonary tuberculosis.

SETTING

106 district health centers in Lima, Peru between September 2009 and September 2012.

DESIGN

Prospective cohort study.

PARTICIPANTS

10 160 household contacts of 3339 index patients with tuberculosis were classified on the basis of the drug resistance profile of the patient: 6189 were exposed to drug susceptible strains of Mycobacterium tuberculosis, 1659 to strains resistant to isoniazid or rifampicin, and 1541 to strains that were multidrug resistant (resistant to isoniazid and rifampicin).

MAIN OUTCOME MEASURES

Tuberculosis infection (positive tuberculin skin test) and the incidence of active disease (diagnosed by positive sputum smear or chest radiograph) after 12 months of follow-up.

RESULTS

Household contacts exposed to patients with multidrug resistant tuberculosis had an 8% (95% confidence interval 4% to 13%) higher risk of infection by the end of follow-up compared with household contacts of patients with drug sensitive tuberculosis. The relative hazard of incident tuberculosis disease did not differ among household contacts exposed to multidrug resistant tuberculosis and those exposed to drug sensitive tuberculosis (adjusted hazard ratio 1.28, 95% confidence interval 0.9 to 1.83).

CONCLUSION

Household contacts of patients with multidrug resistant tuberculosis were at higher risk of tuberculosis infection than contacts exposed to drug sensitive tuberculosis. The risk of developing tuberculosis disease did not differ among contacts in both groups. The evidence invites guideline producers to take action by targeting drug resistant and drug sensitive tuberculosis, such as early detection and effective treatment of infection and disease.

TRIAL REGISTRATION

ClinicalTrials.gov NCT00676754.

Vitamin D status and risk of incident tuberculosis disease: A nested case-control study, systematic review, and individual-participant data meta-analysis

BACKGROUND

Few studies have evaluated the association between preexisting vitamin D deficiency and incident tuberculosis (TB). We assessed the impact of baseline vitamins D levels on TB disease risk.

METHODS AND FINDINGS

We assessed the association between baseline vitamin D and incident TB in a prospective cohort of 6,751 HIV-negative household contacts of TB patients enrolled between September 1, 2009, and August 29, 2012, in Lima, Peru. We screened for TB disease at 2, 6, and 12 months after enrollment. We defined cases as household contacts who developed TB disease at least 15 days after enrollment of the index patient. For each case, we randomly selected four controls from among contacts who did not develop TB disease, matching on gender and year of age. We also conducted a one-stage individual-participant data (IPD) meta-analysis searching PubMed and Embase to identify prospective studies of vitamin D and TB disease until June 8, 2019. We included studies that assessed vitamin D before TB diagnosis. In the primary analysis, we defined vitamin D deficiency as 25-(OH)D < 50 nmol/L, insufficiency as 50-75 nmol/L, and sufficiency as >75nmol/L. We estimated the association between baseline vitamin D status and incident TB using conditional logistic regression in the Lima cohort and generalized linear mixed models in the meta-analysis. We further defined severe vitamin D deficiency as 25-(OH)D < 25 nmol/L and performed stratified analyses by HIV status in the IPD meta-analysis. In the Lima cohort, we analyzed 180 cases and 709 matched controls. The adjusted odds ratio (aOR) for TB risk among participants with baseline vitamin D deficiency compared to sufficient vitamin D was 1.63 (95% CI 0.75-3.52; p = 0.22). We included seven published studies in the meta-analysis and analyzed 3,544 participants. In the pooled analysis, the aOR was 1.48 (95% CI 1.04-2.10; p = 0.03). The aOR for severe vitamin D deficiency was 2.05 (95% CI 0.87-4.87; p trend for decreasing 25-(OH)D levels from sufficient vitamin D to severe deficiency = 0.02). Among 1,576 HIV-positive patients, vitamin D deficiency conferred a 2-fold (aOR 2.18, 95% CI 1.22-3.90; p = 0.01) increased risk of TB, and the aOR for severe vitamin D deficiency compared to sufficient vitamin D was 4.28 (95% CI 0.85-21.45; p = 0.08). Our Lima cohort study is limited by the short duration of follow-up, and the IPD meta-analysis is limited by the number of possible confounding covariates available across all studies.

CONCLUSION

Our findings suggest vitamin D predicts TB disease risk in a dose-dependent manner and that the risk of TB disease is highest among HIV-positive individuals with severe vitamin D deficiency. Randomized control trials are needed to evaluate the possible role of vitamin D supplementation on reducing TB disease risk.

Tuberculosis household accompaniment to improve the contact management cascade: A prospective cohort study

Background

Appropriate management of people exposed in the home to tuberculosis is essential to prevent morbidity. These household contacts, particularly children, should receive preventive therapy to prevent them from falling ill. However, few people receive preventive therapy worldwide. We sought to determine whether a community-based accompaniment intervention could improve tuberculosis contact management.

Methods

We conducted a prospective cohort study of household contacts of tuberculosis patients who initiated treatment during September 2015-June 2016 in Lima, Peru. Enrolled households received an intervention comprising home visits, transport vouchers, assistance coordinating evaluation procedures, and adherence support during preventive therapy. To evaluate the impact of the intervention, we conducted retrospective chart reviews of all patients initiating treatment during 6-month baseline and intervention periods.

Results

We enrolled 314 household contacts of 109 index patients. Of these, 283 (90%) completed evaluation, and 4 (1%) were diagnosed with tuberculosis. Preventive therapy was prescribed for 35/38 (92%) contacts 0–19 years old who were eligible under Peruvian guidelines. Preventive therapy was also prescribed for 6/26 (23%) contacts with unknown eligibility due to lack of a tuberculin skin test (TST), and 20/69 (29%) who were ineligible either because of a negative TST result or exposure to a drug-resistant or extrapulmonary case. Of the 61 contacts who were prescribed preventive therapy, 57 (93%) initiated treatment, and 51 (91%) completed treatment. The proportion of contacts who completed evaluation increased from 42% during the baseline period to 71% during the evaluation period (risk ratio [RR] = 1.73, 95% confidence interval [95% CI]: 1.41–2.13). The proportion of contacts who initiated preventive therapy increased from 15% to 40% (RR = 2.45, 95% CI: 1.42–4.22).

Conclusion

Accompaniment of TB patient households greatly improved the evaluation of household contacts for TB and increased the use of preventive therapy.

Potential effect of household contact management on childhood tuberculosis: a mathematical modelling study

BACKGROUND

Tuberculosis is recognised as a major cause of morbidity and mortality in children, with most cases in children going undiagnosed and resulting in poor outcomes. Household contact management, which aims to identify children with active tuberculosis and to provide preventive therapy for those with HIV or those younger than 5 years, has long been recommended but has very poor coverage globally. New guidelines include widespread provision of preventive therapy to children with a positive tuberculin skin test (TST) who are older than 5 years.

METHODS

In this mathematical modelling study, we provide the first global and national estimates of the impact of moving from zero to full coverage of household contact management (with and without preventive therapy for TST-positive children older than 5 years). We assembled data on tuberculosis notifications, household structure, household contact co-prevalence of tuberculosis disease and infection, the efficacy of preventive therapy, and the natural history of childhood tuberculosis. We used a model to estimate households visited, children screened, and treatment courses given for active and latent tuberculosis. We calculated the numbers of tuberculosis cases, deaths, and life-years lost because of tuberculosis for each intervention scenario and country.

FINDINGS

We estimated that full implementation of household contact management would prevent 159 500 (75% uncertainty interval [UI] 147 000-170 900) cases of tuberculosis and 108 400 (75% UI 98 800-116 700) deaths in children younger than 15 years (representing the loss of 7 305 000 [75% UI 6 663 000-7 874 000] life-years). We estimated that preventing one child death from tuberculosis would require visiting 48 households, screening 77 children, giving 48 preventive therapy courses, and giving two tuberculosis treatments versus no household contact management.

INTERPRETATION

Household contact management could substantially reduce childhood disease and death caused by tuberculosis globally. Funding and research to optimise its implementation should be prioritised.

FUNDING

UK Medical Research Council, US National Institutes of Health, Fulbright Commission, Janssen Global Public Health.

Polyclonal Pulmonary Tuberculosis Infections and Risk for Multidrug Resistance, Lima, Peru

Because within-host Mycobacterium tuberculosis diversity complicates diagnosis and treatment of tuberculosis (TB), we measured diversity prevalence and associated factors among 3,098 pulmonary TB patients in Lima, Peru. The 161 patients with polyclonal infection were more likely than the 115 with clonal or the 2,822 with simple infections to have multidrug-resistant TB.

Prevalence of pyrazinamide resistance and Wayne assay performance analysis in a tuberculosis cohort in Lima, Peru

BACKGROUND

Multidrug-resistant tuberculosis (MDR-TB) regimens often contain pyrazinamide (PZA) even if susceptibility to the drug has not been confirmed. This gap is due to the limited availability and reliability of PZA susceptibility testing.

OBJECTIVES

To estimate the prevalence of PZA resistance using the Wayne assay among TB patients in Lima, Peru, to describe characteristics associated with PZA resistance and to compare the performance of Wayne with that of BACTEC™ MGIT™ 960.

METHODS

PZA susceptibility using the Wayne assay was tested in patients diagnosed with culture-positive pulmonary TB from September 2009 to August 2012. Factors associated with PZA resistance were evaluated. We compared the performance of the Wayne assay to that of MGIT 960 in a convenience sample.

RESULTS

The prevalence of PZA resistance was 6.6% (95%CI 5.8-7.5) among 3277 patients, and 47.7% (95%CI 42.7-52.6) among a subset of 405 MDR-TB patients. In multivariable analysis, MDR-TB (OR 86.0, 95%CI 54.0-136.9) and Latin American-Mediterranean lineage (OR 3.40, 95%CI 2.33-4.96) were associated with PZA resistance. The Wayne assay was in agreement with MGIT 960 in 83.9% of samples (κ 0.66, 95%CI 0.56-0.76).

CONCLUSION

PZA resistance was detected using the Wayne assay in nearly half of MDR-TB patients in Lima. This test can inform the selection and composition of regimens, especially those dependent on additional resistance.

A rapid review of treatment literacy materials for tuberculosis patients

OBJECTIVE

To assess available treatment literacy materials for patients undergoing treatment for tuberculosis (TB).

DESIGN

We conducted a rapid review by searching the US Centers for Disease Control's Find TB Resources website and the websites of health departments and TB-focused organizations. We included English-language documents intended to educate TB patients about anti-tuberculosis treatment. We evaluated the format, readability, and content of documents, and audience. We defined 12 essential content elements based on those previously identified as facilitating human immunodeficiency virus treatment literacy.

RESULTS

Of the 205 documents obtained, 45 were included in our review. The median reading grade level was 7 (IQR 5-8). The median number of essential content elements present was 6 (IQR 4-8), with the most comprehensive document containing 11 of the 12 elements. Only two documents were written for children with TB or their care givers, and two for patients with drug-resistant TB. Many documents contained paternalistic and non-patient-centered language.

CONCLUSION

We found few examples of comprehensive, patient-centered documents. Work is needed to achieve consensus as to the essential elements of TB treatment literacy and to create additional materials for children, patients with drug-resistant TB, and those with lower literacy levels.

Barriers to the treatment of childhood tuberculous infection and tuberculosis disease: a qualitative study

SETTING

In 2012, Peru's National TB Program (NTP) reported approximately 2400 incident cases of tuberculosis (TB) disease in children aged <15 years. Peru's TB burden is concentrated in the Lima metropolitan area, particularly in poor districts such as El Agustino and La Victoria, where this study was conducted.

OBJECTIVE

To identify barriers to the treatment of childhood tuberculous infection and TB disease in Lima from the perspective of front-line providers and patients' families.

DESIGN

We conducted 10 semi-structured focus groups with 53 purposefully sampled primary care providers, community health workers, and parents/guardians of pediatric TB patients. We also completed nine in-depth interviews with National TB Program administrators and pulmonologists specializing in TB. Two authors performed inductive thematic analysis and identified emerging themes.

RESULTS

Four main treatment barriers emerged from the data: 1) dosing errors, 2) time- and labor-intensive preparation and administration of medications, 3) provider concern that isoniazid preventive therapy (IPT) generates isoniazid resistance, and 4) poor adherence to IPT.

CONCLUSION

Our findings highlight the urgent need for child-friendly formulations, provider and parent/guardian education about IPT, and strategies to promote adherence to IPT, including support and supervision by health workers and/or regimens with fewer doses.

Vitamin E Status Is Inversely Associated with Risk of Incident Tuberculosis Disease among Household Contacts

Background

Few studies have previously assessed how pre-existing vitamin E status is associated with risk of tuberculosis (TB) disease progression.

Objective

We evaluated the association between baseline plasma concentrations of 3 vitamin E isomers (α-tocopherol, γ-tocopherol, and δ-tocopherol) and TB disease risk.

Methods

We conducted a case-control study nested within a longitudinal cohort of household contacts (HHCs) of pulmonary TB cases in Lima, Peru. We defined cases as HHCs who developed active TB disease ≥15 d after the diagnosis of the index patient, and we matched each case to 4 control cases who did not develop active TB based on age by year and gender. We used univariate and multivariate conditional logistic regression to calculate ORs for incident TB disease by plasma concentrations of α-tocopherol, γ-tocopherol, and δ-tocopherol.

Results

Among 6751 HIV-negative HHCs who provided baseline blood samples, 180 developed secondary TB during follow-up. After controlling for possible confounders, we found that baseline α-tocopherol deficiency conferred increased risk of incident TB disease (adjusted OR: 1.59; 95% CI: 1.02, 2.50; P = 0.04). Household contacts in the lowest tertile of δ-tocopherol were also at increased risk of progression to TB disease compared to those in the highest tertile (tertile 1 compared with tertile 3, adjusted OR: 2.29; 95% CI: 1.29, 4.09; P-trend = 0.005). We found no association between baseline concentration of γ-tocopherol and incident TB disease.

Conclusions

Vitamin E deficiency was associated with an increased risk of progression to TB disease among HHCs of index TB cases. Assessment of vitamin E status among individuals at high risk for TB disease may play a role in TB control efforts.

Impact of Vitamin A and Carotenoids on the Risk of Tuberculosis Progression

BACKGROUND

Low and deficient levels of vitamin A are common in low- and middle-income countries where tuberculosis burden is high. We assessed the impact of baseline levels of vitamin A and carotenoids on tuberculosis disease risk.

METHODS

We conducted a case-control study nested within a longitudinal cohort of household contacts (HHCs) of pulmonary tuberculosis case patients in Lima, Peru. We defined case patients as human immunodeficiency virus (HIV)-negative HHCs with blood samples in whom tuberculosis disease developed ≥15 days after enrollment of the index patient. For each case patient, we randomly selected 4 controls from among contacts in whom tuberculosis disease did not develop, matching for sex and year of age. We used conditional logistic regression to estimate odds ratios for incident tuberculosis disease by vitamin A and carotenoids levels, controlling for other nutritional and socioeconomic factors.

RESULTS

Among 6751 HIV-negative HHCs with baseline blood samples, 192 had secondary tuberculosis disease during follow-up. We analyzed 180 case patients with viable samples and 709 matched controls. After controlling for possible confounders, we found that baseline vitamin A deficiency was associated with a 10-fold increase in risk of tuberculosis disease among HHCs (adjusted odds ratio, 10.53; 95% confidence interval, 3.73-29.70; P < .001). This association was dose dependent, with stepwise increases in tuberculosis disease risk with each decreasing quartile of vitamin A level.

CONCLUSIONS

Vitamin A deficiency strongly predicted the risk of incident tuberculosis disease among HHCs of patients with tuberculosis. Vitamin A supplementation among individuals at high risk of tuberculosis may provide an effective means of preventing tuberculosis disease.

Addressing tuberculosis patients' medical and socio-economic needs: a comprehensive programmatic approach

OBJECTIVE

For a cohort of patients with tuberculosis in Carabayllo, Peru, we describe the prevalence of medical comorbidities and socio-economic needs, the efforts required by a comprehensive support programme ('TB Cero') to address them and the success of this programme in linking patients to care.

METHODS

Patients diagnosed with tuberculosis in Carabayllo underwent evaluations for HIV, diabetes, mental health and unmet basic needs. For patients initiating treatment during 14 September, 2015-15 May, 2016, we abstracted data from evaluation forms and a support request system. We calculated the prevalence of medical comorbidities and the need for socio-economic support at the time of tuberculosis diagnosis, as well as the proportion of patients successfully linked to care or support.

RESULTS

Of 192 patients, 83 (43%) had at least one medical comorbidity other than tuberculosis. These included eight (4%) patients with HIV, 12 (6%) with diabetes and 62 (32%) deemed at risk for a mental health condition. Of patients who required follow-up for a comorbidity, 100% initiated antiretroviral therapy, 71% attended endocrinology consultations and 66% attended psychology consultations. Of 126 (65%) patients who completed the socio-economic evaluation, 58 (46%) reported already receiving food baskets from the municipality, and 79 (63%) were given additional support, most commonly food vouchers and assistance in accessing health care.

CONCLUSION

Carabayllo tuberculosis patients face many challenges in addition to tuberculosis. A collaborative, comprehensive treatment support programme can achieve high rates of linkage to care for these needs.

Presumptive treatment of multidrug-resistant tuberculosis in household contacts

SETTING

Multidrug-resistant tuberculosis (MDR-TB) is a growing global health threat that often requires presumptive treatment in the absence of drug susceptibility testing (DST) results.

OBJECTIVE

To compare two approaches to the treatment of MDR-TB contacts with no DST results who develop TB disease.

DESIGN

We conducted a retrospective cohort study of adults treated for TB disease who were contacts of patients living with MDR-TB. Subjects had been treated according to one of two presumptive treatment strategies: 1) regimens containing exclusively first-line drugs, and 2) regimens that included both first- and second-line drugs that were adjusted if and when DST results became available. The primary endpoint was a composite of death and treatment failure.

RESULTS

Household contacts of MDR-TB patients who developed TB disease and were treated with first-line regimens were significantly more likely to experience unfavorable end-of-treatment outcomes than those treated with presumptive MDR-TB regimens (RR 2.88, 95%CI 1.24-6.68).

CONCLUSION

Household contacts of MDR-TB patients who develop TB disease but have no DST results should receive regimens containing second-line drugs selected based on the infecting strain of the index patient. Regimens containing only first-line anti-tuberculosis drugs significantly increase the risk of unfavorable outcomes.

Mortality in children diagnosed with tuberculosis: a systematic review and meta-analysis

BACKGROUND

Case fatality ratios in children with tuberculosis are poorly understood-particularly those among children with HIV and children not receiving tuberculosis treatment. We did a systematic review of published work to identify studies of population-representative samples of paediatric (ie, <15 years) tuberculosis cases.

METHODS

We searched PubMed and Embase for reports published in English, French, Portuguese, or Spanish before Aug 12, 2016, that included terms related to tuberculosis, children, mortality, and population representativeness. We also reviewed our own files and reference lists of articles identified by this search. We screened titles and abstracts for inclusion, excluding studies in which outcomes were unknown for 10% or more of the children and publications detailing non-representative samples. We used random-effects meta-analysis to produce pooled estimates of case fatality ratios from the included studies, which we divided into three eras: the pre-treatment era (ie, studies before 1946), the middle era (1946-80), and the recent era (after 1980). We stratified our analyses by whether or not children received tuberculosis treatment, age (0-4 years, 5-14 years), and HIV status.

FINDINGS

We identified 31 papers comprising 35 datasets representing 82 436 children with tuberculosis disease, of whom 9274 died. Among children with tuberculosis included in studies in the pre-treatment era, the pooled case fatality ratio was 21·9% (95% CI 18·1-26·4) overall. The pooled case fatality ratio was significantly higher in children aged 0-4 years (43·6%, 95% CI 36·8-50·6) than in those aged 5-14 years (14·9%, 11·5-19·1). In studies in the recent era, when most children had tuberculosis treatment, the pooled case fatality ratio was 0·9% (95% CI 0·5-1·6). US surveillance data suggest that the case fatality ratio is substantially higher in children with HIV receiving treatment for tuberculosis (especially without antiretroviral therapy) than in those without HIV.

INTERPRETATION

Without adequate treatment, children with tuberculosis, especially those younger than 5 years, are at high risk of death. Children with HIV have an increased mortality risk, even when receiving tuberculosis treatment.

FUNDING

US National Institutes of Health, Janssen Global Public Health.

Nutritional Status and Tuberculosis Risk in Adult and Pediatric Household Contacts

BACKGROUND

Studies show obesity decreases risk of tuberculosis (TB) disease. There is limited evidence on whether high body mass index also protects against TB infection; how very high body mass indices influence TB risk; or whether nutritional status predicts this risk in children. We assessed the impact of body mass index on incident TB infection and disease among adults and children.

METHODS AND FINDINGS

We conducted a prospective cohort study among household contacts of pulmonary TB cases in Lima, Peru. We determined body mass index at baseline and followed participants for one year for TB infection and disease. We used Cox proportional regression analyses to estimate hazard ratios for incident TB infection and disease. We enrolled 14,044 household contacts, and among 6853 negative for TB infection and disease at baseline, 1787 (26.1%) became infected. A total of 406 contacts developed secondary TB disease during follow-up. Body mass index did not predict risk of TB infection but overweight household contacts had significantly decreased risk of TB disease (HR 0.48; 95% CI 0.37-0.64; p <0.001) compared to those with normal weight. Among adults, body mass index ≥ 35 kg/m2 continued to predict a lower risk of TB disease (HR 0.30; 95% CI 0.12-0.74; p 0.009). We found no association between high body mass index and TB infection or disease among children under 12 years of age.

CONCLUSIONS

High body mass index protects adults against TB disease even at levels ≥ 35 kg/m2. This protective effect does not extend to TB infection and is not seen in children.

Multidrug-resistant tuberculosis treatment failure detection depends on monitoring interval and microbiological method

Debate persists about monitoring method (culture or smear) and interval (monthly or less frequently) during treatment for multidrug-resistant tuberculosis (MDR-TB). We analysed existing data and estimated the effect of monitoring strategies on timing of failure detection.

We identified studies reporting microbiological response to MDR-TB treatment and solicited individual patient data from authors. Frailty survival models were used to estimate pooled relative risk of failure detection in the last 12 months of treatment; hazard of failure using monthly culture was the reference.

Data were obtained for 5410 patients across 12 observational studies. During the last 12 months of treatment, failure detection occurred in a median of 3 months by monthly culture; failure detection was delayed by 2, 7, and 9 months relying on bimonthly culture, monthly smear and bimonthly smear, respectively. Risk (95% CI) of failure detection delay resulting from monthly smear relative to culture is 0.38 (0.34–0.42) for all patients and 0.33 (0.25–0.42) for HIV-co-infected patients.

Failure detection is delayed by reducing the sensitivity and frequency of the monitoring method. Monthly monitoring of sputum cultures from patients receiving MDR-TB treatment is recommended. Expanded laboratory capacity is needed for high-quality culture, and for smear microscopy and rapid molecular tests.

Monthly culture monitoring is crucial to earlier detection of treatment failure in MDR-TB patientshttp://ow.ly/w2MI301mK8M