Glycated Hemoglobin Trajectories and Their Association With Treatment Outcomes Among Patients With Pulmonary TB in India: A Prospective Cohort Study

BACKGROUND

Transient hyperglycemia is seen commonly during TB treatment, yet its association with unfavorable treatment outcomes is unclear.

RESEARCH QUESTION

Does an association exist between glycated hemoglobin (HbA1c) trajectories and TB treatment outcomes?

STUDY DESIGN AND METHODS

Adults with pulmonary TB were evaluated prospectively for 18 months after the second HbA1c measurement. HbA1c trajectories during the initial 3 months of treatment were defined as follows: persistent euglycemia, HbA1c < 6.5% at baseline and 3-month follow-up; persistent hyperglycemia, HbA1c ≥ 6.5% at baseline and 3-month follow-up; transient hyperglycemia, HbA1c ≥ 6.5% at baseline and < 6.5% at 3-month follow-up; incident hyperglycemia, HbA1c < 6.5% at baseline and ≥ 6.5% at 3-month follow-up. Multivariable Poisson regression was used to measure the association between HbA1c trajectories and unfavorable treatment outcomes of failure, recurrence, and all-cause mortality.

RESULTS

Of the 587 participants, 443 participants (76%) had persistent euglycemia, 118 participants (20%) had persistent hyperglycemia, and 26 participants (4%) had transient hyperglycemia. One participant had incident hyperglycemia and was excluded. Compared with participants with persistent euglycemia, those with transient hyperglycemia showed a twofold higher risk of experiencing an unfavorable treatment outcome (adjusted incidence rate ratio [aIRR], 2.07; 95% CI, 1.04-4.15) after adjusting for confounders including diabetes treatment, and BMI; we did not find a significant association with persistent hyperglycemia (aIRR, 1.64; 95% CI, 0.71-3.79). Diabetes treatment was associated with a significantly lower risk of unfavorable treatment outcomes (aIRR, 0.38; 95% CI, 0.15-0.95).

INTERPRETATION

Transient hyperglycemia and lack of diabetes treatment was associated with a higher risk of unfavorable treatment outcomes in adults with pulmonary TB.

Health care providers acceptance of default prescribing of TB preventive treatment for people living with HIV in Malawi: a qualitative study

BACKGROUND

Tuberculosis (TB) preventive treatment (TPT) substantially reduces the risk of developing active TB for people living with HIV (PLHIV). We utilized a novel implementation strategy based on choice architecture (CAT) which makes TPT prescribing the default option. Through CAT, health care workers (HCWs) need to "opt-out" when choosing not to prescribe TPT to PLHIV. We assessed the prospective, concurrent, and retrospective acceptability of TPT prescribing among HCWs in Malawi who worked in clinics participating in a cluster randomized trial of the CAT intervention.

METHODS

28 in-depth semi-structured interviews were conducted with HCWs from control (standard prescribing approach) and intervention (CAT approach) clinics. The CAT approach was facilitated in intervention clinics using a default prescribing module built into the point-of-care HIV Electronic Medical Record (EMR) system. An interview guide for the qualitative CAT assessment was developed based on the theoretical framework of acceptability and on the normalization process theory. Thematic analysis was used to code the data, using NVivo 12 software.

RESULTS

We identified eight themes belonging to the three chronological constructs of acceptability. HCWs expressed no tension for changing the standard approach to TPT prescribing (prospective acceptability); however, those exposed to CAT described several advantages, including that it served as a reminder to prescribe TPT and routinized TPT prescribing (concurrent acceptability). Some felt that CAT may reduce HCW´s autonomy and might lead to inappropriate TPT prescribing (retrospective acceptability).

CONCLUSIONS

The default prescribing module for TPT has now been incorporated into the point-of-care EMR system nationally in Malawi. This seems to fit the acceptability of the HCWs. Moving forward, it is important to train HCWs on how the EMR can be leveraged to determine who is eligible for TPT and who is not, while acknowledging the autonomy of HCWs.

Is Tobacco Use Associated With Risk of Recurrence and Mortality Among People With TB?: A Systematic Review and Meta-Analysis

BACKGROUND

Associations between tobacco use and poor TB treatment outcomes are well documented. However, for important outcomes such as TB recurrence or relapse and mortality during treatment, as well as for associations with smokeless tobacco (ST), the evidence is not summarized systematically.

RESEARCH QUESTION

Is tobacco use associated with risk of poor treatment outcomes among people with TB?

STUDY DESIGN AND METHODS

The MEDLINE, Embase, and Cumulative Index of Nursing and Allied Health Literature databases were searched on November 22, 2021. Epidemiologic studies reporting associations between tobacco use and at least one TB treatment outcome were eligible. Independent double-screening, extractions, and quality assessments were undertaken. Random effects meta-analyses were conducted for the two primary review outcomes (TB recurrence or relapse and mortality during treatment), and heterogeneity was explored using subgroups. Other outcomes were synthesized narratively.

RESULTS

Our searches identified 1,249 records, of which 28 were included in the meta-analyses. Based on 15 studies, higher risk of TB recurrence or relapse was found with ever using tobacco vs never using tobacco (risk ratio [RR], 1.78; 95% CI, 1.31-2.43; I2 = 85%), current tobacco use vs no tobacco use (RR, 1.95; 95% CI, 1.59-2.40; I2 = 72%), and former tobacco use vs never using tobacco (RR, 1.84; 95% CI, 1.21-2.80; I2 = 4%); heterogeneity arose from differences in study quality, design, and participant characteristics. Thirty-eight studies were identified for mortality, of which 13 reported mortality during treatment. Ever tobacco use (RR, 1.55; 95% CI, 1.32-1.81; I2 = 0%) and current tobacco use (RR, 1.51; 95% CI, 1.09-2.10; I2 = 87%) significantly increased the likelihood of mortality during treatment among people with TB compared with never using tobacco and not currently using tobacco, respectively; heterogeneity was explained largely by differences in study design. Almost all studies in the meta-analyses scored high or moderate on quality assessments. Narrative synthesis showed that tobacco use was a risk factor for other unfavorable TB treatment outcomes, as previously documented. Evidence on ST was limited, but identified studies suggested an increased risk for poor outcomes with its use compared with not using it.

INTERPRETATION

Tobacco use significantly increases the risk of TB recurrence or relapse and mortality during treatment among people with TB, highlighting the need to address tobacco use to improve TB outcomes.

TRIAL REGISTRY

PROSPERO; No.: CRD42017060821; URL: https://www.crd.york.ac.uk/prospero/.

Reducing HIV-associated post-hospital mortality through home-based care in South Africa: a randomized controlled trial

BACKGROUND

Twenty-three percent of people with HIV (PWH) die within 6-months of hospital discharge. We tested the hypothesis whether a series of structured home visits could reduce mortality.

METHODS

We designed a disease neutral home visit package with up to 6 home visits starting 1-week post-hospitalization and every 2 weeks thereafter. The home visit team used a structured assessment algorithm to evaluate and triage social and medical needs of the participant and provide nutritional support. We compared all-cause mortality 6-months following discharge for the intervention compared to usual care in a pilot randomized trial conducted in South Africa. To inform potential scale-up we also included and separately analyzed a group of people without HIV (PWOH).

RESULTS

We enrolled 125 people with HIV and randomized them 1:1 to the home visit intervention or usual care. Fourteen were late exclusions because of death prior to discharge or delayed discharge leaving 111 for analysis. The median age was 39 years, 31% were men; and 70% had advanced HIV disease. At six months among PWH 4 (7.3%) in the home visit arm and 10 (17.9%) in the usual care arm (p = 0.09) had died. Among the 70 PWOH enrolled overall 6-month mortality was 10.1%. Of those in the home visit arm, 91% received at least one home visit.

CONCLUSIONS

We demonstrated feasibility of delivering post-hospital home visits and demonstrated preliminary efficacy among PWH with a substantial, but not statistically significant, effect size (59% reduction in mortality). COVID-19 related challenges resulted in under-enrollment.

A cross-sectional study of attitudes and behaviors of snuff use and cessation among people with and without HIV in South Africa

Background

Despite a high (48%) prevalence of snuff use among women with HIV in South Africa, little is known of the attitudes and behaviors of use, strategies for cessation, and potential health risks.

Methods

In a cross-sectional study, a questionnaire was administered to adults (≥18 years) with (HIV+) and without HIV (HIV-) who self-reported current snuff use to collect information on demographics, snuff use and cessation attempts, preferred strategies for cessation, other substance use, history of respiratory illness, and mental health.

Results

150 (74 HIV+, 76 HIV-) participants were enrolled; 115 (77%) were daily snuff users, 6 (4%) were current smokers, and 17 (11%) former smokers. Top reasons for current snuff use included improving health (n = 48, 32%), reducing stress (n = 26, 16%), and "being a habit" (n = 38, 25%). Participants believed snuff use to have mostly positive (n = 68, 46%) or no (n = 54, 36%) health impacts, and 57 (38%) participants believed snuff cures headaches. 103 (69%) participants reported a previous quit attempt, and 110 (73%) indicated high interest in quitting snuff. Although 105 (70%) participants indicated that advice from a healthcare provider would aid them in quitting snuff, only 30 (20%) reported ever receiving that advice. A majority of participants (n = 141, 94%) suffer from moderate to high levels of perceived stress, and overall few differences were seen by HIV status.

Conclusions

Education on negative impacts of snuff, advice to quit from healthcare providers, and nicotine replacement therapy should be considered in the development of a snuff cessation program.

Managing Comorbidities, Determinants and Disability at Start and End of TB Treatment under Routine Program Conditions in China

Many patients with tuberculosis (TB) have comorbidities, risk determinants and disability that co-exist at diagnosis, during and after TB treatment. We conducted an observational cohort study in 11 health facilities in China to assess under routine program conditions (i) the burden of these problems at the start and end of TB treatment and (ii) whether referral mechanisms for further care were functional. There were 603 patients registered with drug-susceptible TB who started TB treatment: 84% were symptomatic, 14% had diabetes, 14% had high blood pressure, 19% smoked cigarettes, 10% drank excess alcohol and in 45% the 6 min walking test (6MWT) was abnormal. Five patients were identified with mental health disorders. There were 586 (97%) patients who successfully completed TB treatment six months later. Of these, 18% were still symptomatic, 12% had diabetes (the remainder with diabetes failed to complete treatment), 5% had high blood pressure, 5% smoked cigarettes, 1% drank excess alcohol and 25% had an abnormal 6MWT. Referral mechanisms for the care of comorbidities and determinants worked well except for mental health and pulmonary rehabilitation for disability. There is need for more programmatic-related studies in other countries to build the evidence base for care of TB-related conditions and disability.

Sex Differences in TB Clinical Presentation, Drug Exposure, and Treatment Outcomes in India

BACKGROUND

The role of sex differences in clinical presentation, TB drug pharmacokinetic variables, and treatment outcomes is unclear.

RESEARCH QUESTION

What is the effect of sex on TB disease severity, drug exposure, and treatment outcome?

STUDY DESIGN AND METHODS

This study was a prospective cohort study conducted in India. It assessed TB disease severity; risk of unfavorable treatment outcomes (failure, recurrence, and death) according to sex; and risk factors for unfavorable outcomes stratified according to sex. Effects of sex on the pharmacokinetic variables (maximum concentration and area under the curve) of rifampicin, isoniazid, and pyrazinamide were estimated by using noncompartmental analyses.

RESULTS

Of 1,541 people with microbiologically confirmed TB, 567 (37%) were women. Women had a lower risk of high mycobacterial burden (smear grade ≥ 2 and/or time to detection < 7 days) with an adjusted OR of 0.70 (95% CI, 0.56-0.87). Among the 744 participants who were followed up prospectively, 261 (35%) were women. Women had a lower risk of unfavorable treatment outcomes (adjusted incidence risk ratio, 0.60; 95% CI, 0.43-0.85), mostly because recurrence was lower (adjusted incidence risk ratio, 0.45; 95% CI, 0.23-0.86). Isoniazid (but not rifampicin and pyrazinamide) maximum concentration and area under the curve were significantly higher among women (P < .01) than men. Among women, unfavorable outcomes were more likely among those with cavitary disease, but among men, increased risk of unfavorable outcomes was associated with alcohol use, higher BMI, and lower glycated hemoglobin level.

INTERPRETATION

Women present with lower mycobacterial burden, achieve higher TB drug exposure, and are less likely to have unfavorable treatment outcomes than men. Strategies to improve TB treatment success should take into account sex differences in risk factors for unfavorable outcomes.

Strengthening HIV and HIV co-morbidity care in low- and middle-income countries: insights from behavioural economics to improve healthcare worker behaviour

INTRODUCTION

Despite advances in HIV and HIV co-morbidity service delivery, substantial challenges remain in translating evidence-based interventions into routine practice to bring optimal care and prevention to all populations. While barriers to successful implementation are often multifactorial, healthcare worker behaviour is critical for on-the-ground and in-clinic service delivery. Implementation science offers a systematic approach to understanding service delivery, including approaches to overcoming delivery gaps. Behavioural economics is a field that seeks to understand when and how behaviour deviates from traditional models of decision-making, deviations which are described as biases. Clinical policies and implementation strategies that incorporate an understanding of behavioural economics can add to implementation science approaches and play an important role in bridging the gap between healthcare worker knowledge and service delivery.

DISCUSSION

In HIV care in low- and middle-income countries (LMICs), potential behavioural economic strategies that may be utilized alone or in conjunction with more traditional approaches include using choice architecture to exploit status quo bias and reduce the effects of cognitive load, overcoming the impact of anchoring and availability bias through tailored clinical training and clinical mentoring, reducing the effects of present bias by changing the cost-benefit calculus of interventions with few short-term benefits and leveraging social norms through peer comparison. As with any implementation strategy, understanding the local context and catalysts of behaviour is crucial for success.

CONCLUSIONS

As the focus of HIV care shifts beyond the goal of initiating patients on antiretroviral therapy to a more general retention in high-quality care to support longevity and quality of life, there is an increasing need for innovation to achieve improved care delivery and management. Clinical policies and implementation strategies that incorporate elements of behavioural economic theory, alongside local testing and adaptation, may increase the delivery of evidence-based interventions and improve health outcomes for people living with HIV in LMIC settings.

Number Needed to Screen for Tuberculosis Disease Among Children: A Systematic Review

CONTEXT

Improving detection of pediatric tuberculosis (TB) is critical to reducing morbidity and mortality among children.

OBJECTIVE

We conducted a systematic review to estimate the number of children needed to screen (NNS) to detect a single case of active TB using different active case finding (ACF) screening approaches and across different settings.

DATA SOURCES

We searched 4 databases (PubMed, Embase, Scopus, and the Cochrane Library) for articles published from November 2010 to February 2020.

STUDY SELECTION

We included studies of TB ACF in children using symptom-based screening, clinical indicators, chest x-ray, and Xpert.

DATA EXTRACTION

We indirectly estimated the weighted mean NNS for a given modality, location, and population using the inverse of the weighted prevalence. We assessed risk of bias using a modified AXIS tool.

RESULTS

We screened 27 221 titles and abstracts, of which we included 31 studies of ACF in children < 15 years old. Symptom-based screening was the most common screening modality (weighted mean NNS: 257 [range, 5-undefined], 19 studies). The weighted mean NNS was lower in both inpatient (216 [18-241]) and outpatient (67 [5-undefined]) settings (107 [5-undefined]) compared with community (1117 [28-5146]) and school settings (464 [118-665]). Risk of bias was low.

LIMITATIONS

Heterogeneity in the screening modalities and populations make it difficult to draw conclusions.

CONCLUSIONS

We identified a potential opportunity to increase TB detection by screening children presenting in health care settings. Pediatric TB case finding interventions should incorporate evidence-based interventions and local contextual information in an effort to detect as many children with TB as possible.

Design and implementation of a global site assessment survey among HIV clinics participating in the International epidemiology Databases to Evaluate AIDS (IeDEA) research consortium

INTRODUCTION

Timely descriptions of HIV service characteristics and their evolution over time across diverse settings are important for monitoring the scale-up of evidence-based program strategies, understanding the implementation landscape, and examining service delivery factors that influence HIV care outcomes.

METHODS

The International epidemiology Databases to Evaluate AIDS (IeDEA) consortium undertakes periodic cross-sectional surveys on service availability and care at participating HIV treatment sites to characterize trends and inform the scientific agenda for HIV care and implementation science communities. IeDEA's 2020 general site assessment survey was developed through a consultative, 18-month process that engaged diverse researchers in identifying content from previous surveys that should be retained for longitudinal analyses and in developing expanded and new content to address gaps in the literature. An iterative review process was undertaken to standardize the format of new survey questions and align them with best practices in survey design and measurement and lessons learned through prior IeDEA site assessment surveys.

RESULTS

The survey questionnaire developed through this process included eight content domains covered in prior surveys (patient population, staffing and community linkages, HIV testing and diagnosis, new patient care, treatment monitoring and retention, routine HIV care and screening, pharmacy, record-keeping and patient tracing), along with expanded content related to antiretroviral therapy (differentiated service delivery and roll-out of dolutegravir-based regimens); mental health and substance use disorders; care for pregnant/postpartum women and HIV-exposed infants; tuberculosis preventive therapy; and pediatric/adolescent tuberculosis care; and new content related to Kaposi's sarcoma diagnostics, the impact of COVID-19 on service delivery, and structural barriers to HIV care. The survey was distributed to 238 HIV treatment sites in late 2020, with a 95% response rate.

CONCLUSION

IeDEA's approach for site survey development has broad relevance for HIV research networks and other priority health conditions.

A Cross-Sectional Analysis of the Nicotine Metabolite Ratio and Its Association with Sociodemographic and Smoking Characteristics among People with HIV Who Smoke in South Africa

The nicotine metabolite ratio (NMR) is associated with race/ethnicity but has not been evaluated among smokers in the African region. We conducted a cross-sectional analysis of baseline data from a large randomized, controlled trial for smoking cessation among people with HIV (PWH) in South Africa. Urine samples were analyzed for the NMR and evaluated as a binary variable using a cutoff value of the fourth quartile to determine the fastest metabolizers. The median NMR was 0.31 (IQR: 0.31, 0.32; range: 0.29, 0.57); the cut-point for fast metabolizers was ≥0.3174 ng/mL. A high NMR was not associated with the number of cigarettes per day (OR = 1.10, 95% CI: 0.71, 1.70, p = 0.66) but was associated with 40% lower odds of a quit attempt in the past year (OR = 0.69; 95% CI: 0.44, 1.07, p = 0.09) and alcohol use (OR = 0.59, 95% CI: 0.32, 1.06, p = 0.07). No association was seen with marijuana or HIV clinical characteristics. As we found only minimal variability in the NMR and minimal associations with intensity of smoking, NMR may be of limited clinical value in this population, although it may inform which individuals are less likely to make a quit attempt.

Factors associated with non-completion of TB preventive treatment in Brazil

BACKGROUND: Among Brazilian initiatives to scale up TB preventive therapy (TPT) are the adoption of the 3HP regimen (12 weekly doses of rifapentine and isoniazid [INH]) in 2021 and the implementation in 2018 of the TPT surveillance information system. Since then, 63% of the 76,000 eligible individuals notified completed TPT. Recommended regimens in this period were 6H, 9H (6 or 9 months of INH) and 4R (4 months of rifampicin).OBJECTIVE: To analyse the factors associated with TPT non-completion.METHODS: We analysed the cohort of TPT notifications from 2018 to 2020. Robust variance Poisson regression model was used to verify the association of TPT non-completion with sociodemographic, clinical and epidemiological variables.RESULTS: Of the 39,973 TPT notified in the study period, 8,534 (21.5%) were non-completed, of which 7,858 (92.1%) were lost to follow-up. Age 15-60 years (relative risk [RR] 1.27, 95% confidence interval [95% CI] 1.20-1.35), TPT with isoniazid (RR 1.40, 95% CI 1.19-1.64) and Black/mixed race (RR 1.17, 95% CI 1.09-1.25) were associated with a higher risk of non-completion.CONCLUSION: Individuals in situations of social and financial vulnerability such as being Black/pardo race, younger and on longer TPT regimens were more likely to be associated with TPT incompletion.

Contextualizing and optimizing novel strategies to improve the latent TB continuum of care: Insights from people living with HIV and health care providers in Brazil

Tuberculosis (TB) causes 1 in 3 deaths among people living with HIV (PLHIV). Diagnosing and treating latent tuberculosis infection (LTBI) is critical to reducing TB incidence and mortality. Blood-based screening tests (e.g., QuantiFERON-TB Gold Plus (QFT+)) and shorter-course TB preventive therapy (TPT) regimens such as 3HP (3 months weekly isoniazid-rifapentine) hold significant promise to improve TB outcomes. We qualitatively explored barriers and solutions to optimizing QFT+ and 3HP among PLHIV in three cities in Brazil. We conducted 110 in-depth interviews with PLHIV, health care providers (HCP) and key informants (KI). Content analysis was conducted including the use of case summaries and comparison of themes across populations and contexts. LTBI screening and treatment practices were dependent on HCP's perceptions of whether they were critical to improving TB outcomes. Many HCP lacked a strong understanding of LTBI and perceived the current TPT regimen as complicated. HCP reported that LTBI screening and treatment were constrained by clinic staffing challenges. While PLHIV generally expressed willingness to consider any test or treatment that doctors recommended, they indicated HCP rarely discussed LTBI and TPT. TB testing and treatment requests were constrained by structural factors including financial and food insecurity, difficulties leaving work for appointments, stigma and family responsibilities. QFT+ and 3HP were viewed by all participants as tools that could significantly improve the LTBI cascade by avoiding complexities of TB skin tests and longer LTBI treatment courses. QFT+ and 3HP were perceived to have challenges, including the potential to increase workload on over-burdened health systems if not implemented alongside improved supply chains, staffing, and training, and follow-up initiatives. Multi-level interventions that increase understanding of the importance of LTBI and TPT among HCP, improve patient-provider communication, and streamline clinic-level operations related to QFT+ and 3HP are needed to optimize their impact among PLHIV and reduce TB mortality.

A systematic review and meta-analysis of active case finding for tuberculosis in India

Background

Active case finding (ACF) for tuberculosis (TB) is the cornerstone case-finding strategy in India's national TB policy. However, ACF strategies are highly diverse and pose implementation challenges in routine programming. We reviewed the literature to characterise ACF in India; assess the yield of ACF for different risk groups, screening locations, and screening criteria; and estimate losses to follow-up (LTFU) in screening and diagnosis.

Methods

We searched PubMed, EMBASE, Scopus, and the Cochrane library to identify studies with ACF for TB in India from November 2010 to December 2020. We calculated 1) weighted mean number needed to screen (NNS) stratified by risk group, screening location, and screening strategy; and 2) the proportion of screening and pre-diagnostic LTFU. We assessed risk of bias using the AXIS tool for cross-sectional studies.

Findings

Of 27,416 abstracts screened, we included 45 studies conducted in India. Most studies were from southern and western India and aimed to diagnose pulmonary TB at the primary health level in the public sector after screening. There was considerable heterogeneity in risk groups screened and ACF methodology across studies. Of the 17 risk groups identified, the lowest weighted mean NNS was seen in people with HIV (21, range 3-89, n=5), tribal populations (50, range 40-286, n=3), household contacts of people with TB (50, range 3-undefined, n=12), people with diabetes (65, range 21-undefined, n=3), and rural populations (131, range 23-737, n=5). ACF at facility-based screening (60, range 3-undefined, n=19) had lower weighted mean NNS than at other screening locations. Using the WHO symptom screen (135, 3-undefined, n=20) had lower weighted mean NNS than using criteria of abnormal chest x-ray or any symptom. Median screening and pre-diagnosis loss-to-follow-up was 6% (IQR 4.1%, 11.3%, range 0-32.5%, n=12) and 9.5% (IQR 2.4%, 34.4%, range 0-86.9%, n=27), respectively.

Interpretation

For ACF to be impactful in India, its design must be based on contextual understanding. The narrow evidence base available currently is insufficient for effectively targeting ACF programming in a large and diverse country. Achieving case-finding targets in India requires evidence-based ACF implementation.

Funding

WHO Global TB Programme.

A scoping review of interventions to mitigate common non-communicable diseases among people with TB

BACKGROUND: Recommendations have been made to integrate screening for common non-communicable diseases (NCDs) within TB programs. However, we must ensure screening is tied to evidence-based interventions before scale-up. We aimed to map the existing evidence regarding interventions that address NCDs that most commonly affect people with TB.METHODS: We systematically searched PubMed, Medline, and Embase for studies that evaluated interventions to mitigate respiratory disease, cardiovascular disease, alcohol and substance use disorder, and mental health disorders among people with TB. We excluded studies that only screened for comorbidity but resulted in no further intervention. We also excluded studies focusing on smoking cessation interventions for which evidence-based guidelines are well established.RESULTS: The search identified 20 studies that met our inclusion criteria. The most commonly evaluated intervention was referral for diabetes care (6 studies). Other interventions included pulmonary rehabilitation (5 studies), care programs for alcohol use disorder (4 studies), and psychosocial support or individual counselling (5 studies).CONCLUSION: There is limited robust evidence to support identified interventions in changing individual outcomes, and a significant knowledge gap remains on the long-term durability of the interventions´ clinical benefit, reach, and effectiveness. Implementation research demonstrating feasibility and effectiveness is needed before scaling up.

Tuberculosis (TB) Aftermath: study protocol for a hybrid type I effectiveness-implementation non-inferiority randomized trial in India comparing two active case finding (ACF) strategies among individuals treated for TB and their household contacts

BACKGROUND

Approximately 7% of all reported tuberculosis (TB) cases each year are recurrent, occurring among people who have had TB in the recent or distant past. TB recurrence is particularly common in India, which has the largest TB burden worldwide. Although patients recently treated for TB are at high risk of developing TB again, evidence around effective active case finding (ACF) strategies in this population is scarce. We will conduct a hybrid type I effectiveness-implementation non-inferiority randomized trial to compare the effectiveness, cost-effectiveness, and feasibility of two ACF strategies among individuals who have completed TB treatment and their household contacts (HHCs).

METHODS

We will enroll 1076 adults (≥ 18 years) who have completed TB treatment at a public TB unit (TU) in Pune, India, along with their HHCs (averaging two per patient, n = 2152). Participants will undergo symptom-based ACF by existing healthcare workers (HCWs) at 6-month intervals and will be randomized to either home-based ACF (HACF) or telephonic ACF (TACF). Symptomatic participants will undergo microbiologic testing through the program. Asymptomatic HHCs will be referred for TB preventive treatment (TPT) per national guidelines. The primary outcome is rate per 100 person-years of people diagnosed with new or recurrent TB by study arm, within 12 months following treatment completion. The secondary outcome is proportion of HHCs < 6 years, by study arm, initiated on TPT after ruling out TB disease. Study staff will collect socio-demographic and clinical data to identify risk factors for TB recurrence and will measure post-TB lung impairment. In both arms, an 18-month "mop-up" visit will be conducted to ascertain outcomes. We will use the RE-AIM framework to characterize implementation processes and explore acceptability through in-depth interviews with index patients, HHCs and HCWs (n = 100). Cost-effectiveness will be assessed by calculating the incremental cost per TB case detected within 12 months and projected for disability-adjusted life years averted based on modeled estimates of morbidity, mortality, and time with infectious TB.

DISCUSSION

This novel trial will guide India's scale-up of post-treatment ACF and provide an evidence base for designing strategies to detect recurrent and new TB in other high burden settings.

TRIAL REGISTRATION

NCT04333485 , registered April 3, 2020. CTRI/2020/05/025059 [Clinical Trials Registry of India], registered May 6 2020.

Number needed to screen for TB in clinical, structural or occupational risk groups

BACKGROUND: Screening for active TB using active case-finding (ACF) may reduce TB incidence, prevalence, and mortality; however, yield of ACF interventions varies substantially across populations. We systematically reviewed studies reporting on ACF to calculate the number needed to screen (NNS) for groups at high risk for TB.METHODS: We conducted a literature search for studies reporting ACF for adults published between November 2010 and February 2020. We determined active TB prevalence detected through various screening strategies and calculated crude NNS for - TB confirmed using culture or Xpert^® MTB/RIF, and weighted mean NNS stratified by screening strategy, risk group, and country-level TB incidence.RESULTS: We screened 27,223 abstracts; 90 studies were included (41 in low/moderate and 49 in medium/high TB incidence settings). High-risk groups included inpatients, outpatients, people living with diabetes (PLWD), migrants, prison inmates, persons experiencing homelessness (PEH), healthcare workers, and miners. Screening strategies included symptom-based screening, chest X-ray and Xpert testing. NNS varied widely across and within incidence settings based on risk groups and screening methods. Screening tools with higher sensitivity (e.g., Xpert, CXR) were associated with lower NNS estimates.CONCLUSIONS: NNS for ACF strategies varies substantially between adult risk groups. Specific interventions should be tailored based on local epidemiology and costs.

Concomitant pulmonary disease is common among patients with extrapulmonary TB

BACKGROUND :

Microbiologic screening of extrapulmonary TB (EPTB) patients could inform recommendations for aerosol precautions and close contact prophylaxis. However, this is currently not routinely recommended in India. Therefore, we estimated the proportion of Indian patients with EPTB with microbiologic evidence of pulmonary TB (PTB).

METHODS :

We characterized baseline clinical, radiological and sputum microbiologic data of 885 adult and pediatric TB patients in Chennai and Pune, India, between March 2014 and November 2018.

RESULTS :

Of 277 patients with EPTB, enhanced screening led to the identification of 124 (45%) with concomitant PTB, including 53 (19%) who reported a cough >2 weeks; 158 (63%) had an abnormal CXR and 51 (19%) had a positive sputum for TB. Of 70 participants with a normal CXR and without any cough, 14 (20%) had a positive sputum for TB. Overall, the incremental yield of enhanced screening of patients with EPTB to identify concomitant PTB disease was 14% (95% CI 12–16).

CONCLUSIONS :

A high proportion of patients classified as EPTB in India have concomitant PTB. Our results support the need for improved symptom and CXR screening, and recommends routine sputum TB microbiology screening of all Indian patients with EPTB.

Whole Genome Sequencing Assessing Impact of Diabetes Mellitus on Tuberculosis Mutations and Type of Recurrence in India

BACKGROUND

Evidence describing the impact of diabetes mellitus (DM) on the recurrence and mutation rate of Mycobacterium tuberculosis (Mtb) is limited.

METHODS

This study was nested in 3 cohort studies of tuberculosis (TB) patients with and without DM in India. Paired Mtb isolates recovered at baseline and treatment failure/recurrence underwent whole genome sequencing. We compared acquisition of single-nucleotide polymorphisms (SNPs), TB drug resistance mutations, and type of recurrence (endogenous reactivation [<8 SNPs] or exogenous reinfection [≥8 SNPs]) by DM status.

RESULTS

Of 1633 enrolled in the 3 parent cohorts, 236 (14.5%) had microbiologically confirmed TB treatment failure/recurrence; 76 Mtb isolate pairs were available for sequencing (22 in TB-DM and 54 in TB-only). The SNP acquisition rate was overall was 0.43 (95% confidence interval [CI], .25-.64) per 1 person-year (PY); 0.77 (95% CI, .40-1.35) per 1 PY, and 0.44 (95% CI, .19-.86) per 1 PY at treatment failure and recurrence, respectively. Significant difference in SNP rates by DM status was seen at recurrence (0.21 [95% CI, .04-.61]) per 1 PY for TB-only vs 1.28 (95% CI, .41-2.98) per 1 PY for TB-DM; P = .02). No significant difference in SNP rates by DM status was observed at treatment failure. Acquired TB drug resistance was seen in 4 of 18 (22%) in TB-DM vs 4 of 45 (9%) in TB-only (P = .21). Thirteen (17%) participants had exogenous reinfection; the reinfection rate at recurrence was 25% (3/12) for TB-DM vs 17% (4/24) in TB-only (P = .66).

CONCLUSIONS

Considerable intrahost Mtb mutation rates were present at recurrence among patients with DM in India. One-fourth of patients with DM had exogenous reinfection at recurrence.

Host lipidome and tuberculosis treatment failure

INTRODUCTION

Host lipids play important roles in tuberculosis (TB) pathogenesis. Whether host lipids at TB treatment initiation (baseline) affect subsequent treatment outcomes has not been well characterised. We used unbiased lipidomics to study the prospective association of host lipids with TB treatment failure.

METHODS

A case-control study (n=192), nested within a prospective cohort study, was used to investigate the association of baseline plasma lipids with TB treatment failure among adults with pulmonary TB. Cases (n=46) were defined as TB treatment failure, while controls (n=146) were those without failure. Complex lipids and inflammatory lipid mediators were measured using liquid chromatography mass spectrometry techniques. Adjusted least-square regression was used to assess differences in groups. In addition, machine learning identified lipids with highest area under the curve (AUC) to classify cases and controls.

RESULTS

Baseline levels of 32 lipids differed between controls and those with treatment failure after false discovery rate adjustment. Treatment failure was associated with lower baseline levels of cholesteryl esters and oxylipin, and higher baseline levels of ceramides and triglycerides compared to controls. Two cholesteryl ester lipids combined in a unique classifier model provided an AUC of 0.79 (95% CI 0.65-0.93) in the test dataset for prediction of TB treatment failure.

CONCLUSIONS

We identified lipids, some with known roles in TB pathogenesis, associated with TB treatment failure. In addition, a lipid signature with prognostic accuracy for TB treatment failure was identified. These lipids could be potential targets for risk-stratification, adjunct therapy and treatment monitoring.

Household contact tracing with intensified tuberculosis and HIV screening in South Africa: a cluster randomised trial

Background

Household contact tracing for tuberculosis (TB) may facilitate diagnosis and access to TB preventive treatment (TPT). We investigated whether household contact tracing and intensive TB/human immunodeficiency virus (HIV) screening would improve TB-free survival.

Methods

Household contacts of index TB patients in 2 South African provinces were randomized to home tracing and intensive HIV/TB screening or standard of care (SOC; clinic referral letters). The primary outcome was incident TB or death at 15 months. Secondary outcomes included tuberculin skin test (TST) positivity in children ≤14 years and undiagnosed HIV.

Results

From December 2016 through March 2019, 1032 index patients (4459 contacts) and 1030 (4129 contacts) were randomized to the intervention and SOC arms. Of intervention arm contacts, 3.2% (69 of 2166) had prevalent microbiologically confirmed TB. At 15 months, the cumulative incidence of TB or death did not differ between the intensive screening (93 of 3230, 2.9%) and SOC (80 of 2600, 3.1%) arms (hazard ratio, 0.90; 95% confidence interval [CI], .66–1.24). TST positivity was higher in the intensive screening arm (38 of 845, 4.5%) compared with the SOC arm (15 of 800, 1.9%; odds ratio, 2.25; 95% CI, 1.07–4.72). Undiagnosed HIV was similar between arms (41 of 3185, 1.3% vs 32 of 2543, 1.3%; odds ratio, 1.02; 95% CI, .64–1.64).

Conclusions

Household contact tracing with intensive screening and referral did not reduce incident TB or death. Providing referral letters to household contacts of index patients is an alternative strategy to home visits.

Clinical Trials Registration

ISRCTN16006202.

Do community-based active case-finding interventions have indirect impacts on wider TB case detection and determinants of subsequent TB testing behaviour? A systematic review

Community-based active case-finding (ACF) may have important impacts on routine TB case-detection and subsequent patient-initiated diagnosis pathways, contributing "indirectly" to infectious diseases prevention and care. We investigated the impact of ACF beyond directly diagnosed patients for TB, using routine case-notification rate (CNR) ratios as a measure of indirect effect. We systematically searched for publications 01-Jan-1980 to 13-Apr-2020 reporting on community-based ACF interventions compared to a comparison group, together with review of linked manuscripts reporting knowledge, attitudes, and practices (KAP) outcomes or qualitative data on TB testing behaviour. We calculated CNR ratios of routine case-notifications (i.e. excluding cases identified directly through ACF) and compared proxy behavioural outcomes for both ACF and comparator communities. Full text manuscripts from 988 of 23,883 abstracts were screened for inclusion; 36 were eligible. Of these, 12 reported routine notification rates separately from ACF intervention-attributed rates, and one reported any proxy behavioural outcomes. Two further studies were identified from screening 1121 abstracts for linked KAP/qualitative manuscripts. 8/12 case-notification studies were considered at critical or serious risk of bias. 8/11 non-randomised studies reported bacteriologically-confirmed CNR ratios between 0.47 (95% CI:0.41-0.53) and 0.96 (95% CI:0.94-0.97), with 7/11 reporting all-form CNR ratios between 0.96 (95% CI:0.88-1.05) and 1.09 (95% CI:1.02-1.16). One high-quality randomised-controlled trial reported a ratio of 1.14 (95% CI 0.91-1.43). KAP/qualitative manuscripts provided insufficient evidence to establish the impact of ACF on subsequent TB testing behaviour. ACF interventions with routine CNR ratios >1 suggest an indirect effect on wider TB case-detection, potentially due to impact on subsequent TB testing behaviour through follow-up after a negative ACF test or increased TB knowledge. However, data on this type of impact are rarely collected. Evaluation of routine case-notification, testing and proxy behavioural outcomes in intervention and comparator communities should be included as standard methodology in future ACF campaign study designs.

Brief Report: Yield of Repeat Tuberculin Skin Testing for People Living With HIV in Brazil

OBJECTIVES

In Brazil, annual tuberculin skin tests (TSTs) are recommended for people living with HIV (PLWH) with CD4 >350, with tuberculosis preventive therapy provided on test conversion. We aimed to determine the yield of repeat TSTs for PLWH.

DESIGN

Secondary analysis of the stepped-wedge, cluster-randomized THRio trial for isoniazid preventive therapy (IPT) to prevent tuberculosis (TB).

METHODS

We analyzed data from newly registered PLWH with negative baseline TST results. We calculated the number of TST conversions after 1 and/or 2 years among patients eligible for follow-up TSTs, the proportion of converters initiating IPT, and incidence of TB/death.

RESULTS

Among 1770 PLWH with a negative baseline TST, 679 (38%) were female and median age was 36 years (IQR 29-43). Eighty-six (5%) developed TB or died within 1 year. Among 1684 eligible for a follow-up 1-year TST, 582 (35%) were tested and 53 (9%) were positive. Forty-nine converters (92%) started IPT. Of 529 patients with a negative 1-year TST, 7 (1%) developed TB or died over the following year. Of 522 patients eligible for a 2-year TST, 158 (30%) were tested and 13 (8%) were positive. Ten converters (77%) started IPT. Of 1102 patients who did not receive a 1-year TST, 33 (3%) developed TB or died. Of the 1069 patients eligible for a 2-year TST, 259 (24%) were tested and 34 (13%) were positive. Thirty converters (88%) started IPT.

CONCLUSIONS

In this cohort of PLWH in Brazil, TST conversion was high among those retested, but only 48% received a follow-up TST within 2 years.

Tuberculosis Pathways to Care and Transmission of Multidrug-Resistance in India

Rationale

India is experiencing a regional increase in cases of multidrug-resistant tuberculosis (MDR-TB).

Objectives

Given the complexity of MDR-TB diagnosis and care, we sought to address key knowledge gaps in MDR risk factors, care delays, and drivers of delay to help guide disease control.

Methods

From January 2018 to September 2019, we conducted interviews with adults registered with the National TB Elimination Program for MDR (n = 128) and non–MDR-TB (n = 269) treatment to quantitatively and qualitatively study care pathways. We collected treatment records and GeneXpert-TB/RIF diagnostic reports.

Measurements and Main Results

MDR-TB was associated with young age and crowded residence. GeneXpert rifampicin resistance diversity was measured at 72.5% Probe E. Median time from symptom onset to diagnosis of MDR was 90 days versus 60 days for non-MDR, Wilcoxon P < 0.01. Delay decreased by a median of 30 days among non-MDR patients with wider access to GeneXpert, Wilcoxon P = 0.02. Pathways to care were complex, with a median (interquartile range) of 4 (3–5) and 3 (2–4) encounters for MDR and non-MDR, respectively. Of patients with MDR-TB, 68% had their first encounter in the private sector, and this was associated with a larger number of subsequent healthcare encounters and catastrophic expenditure.

Conclusions

The association of MDR with young age, crowding, and low genotypic diversity raises concerns of ongoing MDR transmission fueled by long delays in care. Delays are decreasing with GeneXpert use, suggesting the need for routine use in presumptive TB. Qualitatively, we identify the need to improve patient retention in the National TB Elimination Program and highlight patients’ trust relationship with private providers.

A systematic review of the number needed to screen for active TB among people living with HIV

BACKGROUND: Systematic screening for active TB is recommended for all people living with HIV (PLWH); however, case detection remains poor globally. We investigated the yield of active case finding (ACF) by calculating the number needed to screen (NNS) to detect a case of active TB among PLWH.METHODS: We identified studies reporting ACF for TB among PLWH published from November 2010 to February 2020. We calculated crude NNS for Xpert- or culture-confirmed TB and weighted mean NNS stratified by screening approach, population/risk group, and country TB burden.RESULTS: Of the 27,221 abstracts screened, we identified 58 studies eligible for inclusion, including 5 in low/moderate TB incidence settings and 53 in medium/high incidence settings. Populations screened for TB included inpatients, outpatients not receiving antiretroviral therapy (ART), outpatients receiving ART, those with CD4 < 200 cells/µL, children aged ≤15 years, pregnant PLWH, and PLWH in prisons. Screening tools included symptom-based screening, chest X-ray, C-reactive protein levels, and Xpert. The weighted mean NNS varied across groups but was consistently low, ranging from 4 among inpatients in moderate/high TB burden settings to 137 among pregnant PLWH in moderate/high TB burden settings.CONCLUSIONS: ACF is a high yield intervention among PLWH. Approaches to screening should be tailored to local epidemiological and health-system contexts, and sensitive screening tools such as Xpert should be implemented where feasible.

Community-based active case-finding interventions for tuberculosis: a systematic review

BACKGROUND

Community-based active case-finding interventions might identify and treat more people with tuberculosis disease than standard case detection. We aimed to assess whether active case-finding interventions can affect tuberculosis epidemiology in the wider community.

METHODS

We did a systematic review by searching PubMed, Embase, Scopus, and Cochrane Library for studies that compared tuberculosis case notification rates, tuberculosis disease prevalence, or tuberculosis infection prevalence or incidence in children, between populations exposed and unexposed to active case-finding interventions. We included studies published in English between Jan 1, 1980, and April 13, 2020. Studies of active case-finding in the general population, in populations perceived to be at high risk for tuberculosis, and in closed settings were included, whereas studies of tuberculosis screening at health-care facilities, among household contacts, or among children only, and studies that screened fewer than 1000 people were excluded. To estimate effectiveness, we extracted or calculated case notification rates, prevalence of tuberculosis disease, and incidence or prevalence of tuberculosis infection in children, and compared ratios of these outcomes between groups that were exposed or not exposed to active case-finding interventions.

RESULTS

27 883 abstracts were screened and 988 articles underwent full text review. 28 studies contributed data for analysis of tuberculosis case notifications, nine for prevalence of tuberculosis disease, and two for incidence or prevalence of tuberculosis infection in children. In one cluster-randomised trial in South Africa and Zambia, an active case-finding intervention based on community mobilisation and sputum drop-off did not affect tuberculosis prevalence, whereas, in a cluster-randomised trial in Vietnam, an active case-finding intervention based on sputum tuberculosis tests for everyone reduced tuberculosis prevalence in the community. We found inconsistent, low-quality evidence that active case-finding might increase the number of cases of tuberculosis notified in populations with structural risk factors for tuberculosis.

INTERPRETATION

Community-based active case-finding for tuberculosis might be effective in changing tuberculosis epidemiology and thereby improving population health if delivered with high coverage and intensity. If possible, active case-finding projects should incorporate a well designed, robust evaluation to contribute to the evidence base and help elucidate which delivery methods and diagnostic strategies are most effective.

FUNDING

WHO Global TB Programme.

Diabetes Mellitus and Tuberculosis Treatment Outcomes in Pune, India

Background

Diabetes mellitus (DM) increases the risk of tuberculosis (TB) disease. Knowledge of the impact of DM on TB treatment outcomes is primarily based on retrospective studies.

Methods

We conducted a prospective cohort study of new pulmonary TB patients with and without DM (TB-DM and TB only) in India. The association of DM with a composite unfavorable TB treatment outcome (failure, recurrence, mortality) over 18 months was determined, and the effect of DM on all-cause mortality and early mortality (death during TB treatment) was assessed.

Results

Of 799 participants, 574 (72%) had TB only and 225 (28%) had TB-DM. The proportion of patients with DM who experienced the composite outcome was 20%, as compared with 21% for TB-only participants (adjusted hazard ratio [aHR], 1.13; 95% CI, 0.75–1.70). Mortality was higher in participants with DM (10% vs 7%), and early mortality was substantially higher among patients with DM (aHR, 4.36; 95% CI, 1.62–11.76).

Conclusions

DM was associated with early mortality in this prospective cohort study, but overall unfavorable outcomes were similar to participants without DM. Interventions to reduce mortality during TB treatment among people with TB-DM are needed.

Unhealthy alcohol use independently associated with unfavorable TB treatment outcomes among Indian men

BACKGROUND: Approximately 10% of incident TB cases worldwide are attributable to alcohol. However, evidence associating alcohol with unfavorable TB treatment outcomes is weak.METHODS: We prospectively evaluated men (≥18 years) with pulmonary TB in India for up to 24 months to investigate the association between alcohol use and treatment outcomes. Unhealthy alcohol use was defined as a score of ≥4 on the Alcohol Use Disorders Identification Test-Concise (AUDIT-C) scale at entry. Unfavorable TB treatment outcomes included failure, recurrence, and all-cause mortality, analyzed as composite and independent endpoints.RESULTS: Among 751 men, we identified unhealthy alcohol use in 302 (40%). Median age was 39 years (IQR 28-50); 415 (55%) were underweight (defined as a body mass index [BMI] <18.5 kg/m²); and 198 (26%) experienced an unfavorable outcome. Unhealthy alcohol use was an independent risk factor for the composite unfavorable outcome (adjusted incidence rate ratio [aIRR] 1.47, 95% CI 1.05-2.06; P = 0.03) and death (aIRR 1.90, 95% CI 1.08-3.34; P = 0.03), specifically. We found significant interaction between AUDIT-C and BMI; underweight men with unhealthy alcohol use had increased risk of unfavorable outcomes (aIRR 2.22, 95% CI 1.44-3.44; P < 0.001) compared to men with BMI ≥18.5 kg/m² and AUDIT-C <4.CONCLUSION: Unhealthy alcohol use was independently associated with unfavorable TB treatment outcomes, highlighting the need for integrating effective alcohol interventions into TB care.

Isoniazid preventive therapy plus antiretroviral therapy for the prevention of tuberculosis: a systematic review and meta-analysis of individual participant data

BACKGROUND

Isoniazid preventive therapy prevents active tuberculosis in people with HIV, but previous studies have found no evidence of benefit in people with HIV who had a negative tuberculin skin test, and a non-significant effect on mortality. We aimed to estimate the effect of isoniazid preventive therapy given with antiretroviral therapy (ART) for the prevention of tuberculosis and death among people with HIV across population subgroups.

METHODS

We searched PubMed, Embase, the Cochrane database, and conference abstracts from database inception to Jan 15, 2019, to identify potentially eligible randomised trials. Eligible studies were trials that enrolled HIV-positive adults (age ≥15 years) taking ART who were randomly assigned to either daily isoniazid preventive therapy plus ART or ART alone and followed up longitudinally for outcomes of incident tuberculosis and mortality. We approached all authors of included trials and requested individual participant data: coprimary outcomes were relative risk of incident tuberculosis and all-cause mortality. We did a single-stage meta-analysis of individual participant data using stratified Cox-proportional hazards models. We did prespecified subgroup analyses by sex, CD4 cell count, and evidence of immune sensitisation to tuberculosis (indicated by tuberculin skin test or interferon-γ release assays [IGRAs]). We also assessed the relative risk of liver injury in an additional prespecified analysis. This study is registered with PROSPERO, CRD42019121400.

FINDINGS

Of 838 records, we included three trials with data for 2611 participants and 8584·8 person-years of follow-up for the outcome of incident tuberculosis, and a subset of 2362 participants with 8631·6 person-years of follow-up for the coprimary outcome of all-cause mortality. Risk for tuberculosis was lower in participants given isoniazid preventive therapy and ART than participants given ART alone (hazard ratio [HR] 0·68, 95% CI 0·49-0·95, p=0·02). Risk of all-cause mortality was lower in participants given isoniazid preventive therapy and ART than participants given ART alone, but this difference was non-significant (HR 0·69, 95% CI 0·43-1·10, p=0·12). Participants with baseline CD4 counts of less than 500 cells per μL had increased risk of tuberculosis, but there was no significant difference in the benefit of isoniazid preventive therapy with ART by sex, baseline CD4 count, or results of tuberculin skin test or IGRAs. 65 (2·5%) of 2611 participants had raised alanine aminotransferase, but data were insufficient to calculate an HR.

INTERPRETATION

Isoniazid preventive therapy with ART prevents tuberculosis across demographic and HIV-specific and tuberculosis-specific subgroups, which supports efforts to further increase use of isoniazid preventive therapy with ART broadly among people living with HIV.

FUNDING

National Institutes of Health and National Institute of Allergy and Infectious Diseases.

Secure Delivery of HIV-Related and Tuberculosis Laboratory Results to Patient Cell Phones: A Pilot Comparative Study

South Africa processes 5.1 million HIV CD4, viral load (VL), and tuberculosis (TB) tests annually. This pilot non-randomized trial in South Africa explored an intervention ("MatlaMobile") to deliver laboratory results via mobile phone. Adults completing CD4, VL, and/or TB laboratory tests were enrolled-either receiving results by returning to clinic (control, n = 174) or mobile phone (intervention, n = 226). Study staff instructed control participants to return within 6 days (standard-of-care). MatlaMobile instructed intervention participants with clinically actionable results requiring intervention or treatment change (i.e., < 200 CD4 cells per milliliter, ≥ 400 viral copies per milliliter, or TB positive) to return immediately. A greater proportion of intervention participants than controls saw their results within 7 days of enrollment (73% vs. 8.6%, p < 0.001). Among participants instructed to return, more intervention participants (20%, n = 14/70) returned than controls (8.6%, n = 15/174, p = 0.02). MatlaMobile demonstrated that patients can quickly receive and respond appropriately to digital delivery of health information.

The Impact of Hypertension and Use of Calcium Channel Blockers on Tuberculosis Treatment Outcomes

BACKGROUND

Hypertension induces systemic inflammation, but its impact on the outcome of infectious diseases like tuberculosis (TB) is unknown. Calcium channel blockers (CCB) improve TB treatment outcomes in pre-clinical models, but their effect in patients with TB remain unclear.

METHODS

This retrospective cohort study, including all patients > 18 years receiving treatment for culture-confirmed, drug-sensitive TB from 2000 to 2016 at the National Taiwan University Hospital, assessed the association of hypertension and CCB use with all-cause and infection-related mortality during the first 9 months of TB treatment, as well as sputum-smear microscopy and sputum-culture positivity at 2 and 6 months.

RESULTS

1052 of the 2894 patients (36.4%) had hypertension. Multivariable analysis revealed that hypertension was associated with increased mortality due to all causes (HR 1.57, 95% confidence interval[CI], 1.23-1.99) and infections (HR 1.87, 95%CI, 1.34-2.6), but there was no statistical difference in microbiological outcomes when stratified based on hypertensive group. Dihydropyridine-CCB (DHP-CCB) use was associated with reduced all-cause mortality (HR 0.67, 95%CI: 0.45-0.98) only by univariate Cox regression. There was no association between DHP-CCB use and infection-related mortality (HR 0.78, 95%CI: 0.46-1.34) or microbiological outcomes in univariate or multivariate regression analyses.

CONCLUSIONS

Patients with hypertension have increased all-cause mortality and infection-related mortality during the 9 months following TB treatment initiation. DHP-CCB use may lower all-cause mortality in TB patients with hypertension. The presence of hypertension or the use of CCB did not result in a significant change in microbiological outcomes.

Choice architecture-based prescribing tool for TB preventive therapy: a pilot study in South Africa

Background

All people with HIV who screen negative for active tuberculosis (TB) should receive isoniazid preventive therapy (IPT). IPT implementation remains substantially below the 90% WHO target. This study sought to further understanding of IPT prescription by piloting a simplified prescribing approach.

Setting

Primary care clinics in Matlosana, South Africa.

Design

This was a mixed-methods implementation study.

Methods

Nine providers were recruited and underwent training on 2018 WHO guidelines. A simplified prescribing tool containing antiretroviral therapy (ART) and IPT prescriptions was introduced into the workflow for 2 weeks. Prescription data were collected from file review. Interviews were conducted with prescribers.

Results

During the study period, 41 patients were evaluated for ART initiation; 34 (83%) files used the simplified prescribing tool. Thirty-seven (90%) patients were eligible for same-day ART and IPT initiation, of whom 36 (97%) received IPT prescription. Qualitative interviews identified the following barriers to IPT prescription: cognitive burden, extensive documentation, limited management support, paucity of training, stock-outs, and patient-related factors. Provider acceptability of the tool was favorable, with unanimous recommendation to colleagues on the basis of streamlining documentation and reminding to prescribe.

Conclusions

This simplified prescribing device for IPT was feasible to implement. Streamlining documentation and reminding providers to prescribe can reduce work-flow barriers to IPT provision.

Delays and barriers to early treatment initiation for childhood tuberculosis in India

BACKGROUND: India accounts for 27% of global childhood tuberculosis (TB) burden. Understanding barriers to early diagnosis and treatment in children may improve care and outcomes.METHODS: A cross-sectional study was performed among 89 children initiated on anti-TB treatment from a public hospital in Pune during 2016, using a structured questionnaire and hospital records. Health care providers (HCPs) were defined as medical personnel consulted about the child's TB symptoms. Time-to-treatment initiation (TTI) was defined as the number of days between onset of TB symptoms and anti-TB treatment initiation. Based on Revised National TB Control Programme recommendations, delayed TTI was defined as >28 days.RESULTS: Sixty-seven (75%) of 89 enrolled children had significant TTI delays (median 51 days, interquartile range [IQR] 27-86). Sixty-six (74%) children visited 1-8 HCPs in the private sector before approaching the public sector. The median HCP delay was 28 days (IQR 10-75). Bacille Calmette-Guérin vaccination (aOR 10.96, P = 0.04) and loss of appetite (aOR 4.44, P = 0.04) were associated with delayed TTI.CONCLUSION: The majority of the children had TTI delays due to delays by HCPs in the private sector. Strengthening HCP competency in TB symptom screening and encouraging early referrals are crucial for rapid scaling up of early treatment initiation in childhood TB.

COach2Quit: A Pilot Randomized Controlled Trial of a Personal Carbon Monoxide Monitor for Smoking Cessation

INTRODUCTION

Mobile phone-based messaging support and biomarker feedback independently show evidence of increasing an individual's likelihood of quitting smoking. However, the combination of these two strategies to facilitate smoking cessation has not been adequately explored.

METHODS

We conducted a randomized controlled trial in Baltimore, Maryland, to assess the efficacy of COach2Quit, a smartphone application that provides exhaled carbon monoxide readings with message support. The primary outcome was self-reported and biochemically verified smoking cessation at 30-day follow-up. Secondary outcomes were reduction in smoking, motivation to quit, and engagement and satisfaction with COach2Quit. An intention-to-treat analysis was conducted.

RESULTS

Adult smokers were randomized 1:1 to receive brief advice and COach2Quit (intervention, n = 50) or brief advice only (control, n = 52). Thirteen participants were lost to follow-up. At 30-day follow-up, one participant in each arm quit smoking. Median change in carbon monoxide levels (in parts per million (ppm)) (intervention: -3.0 [interquartile range (IQR) -12.0, 2.0]; control: -2.5 [IQR -9.0, 2.0]) and median change in number of cigarettes smoked per day (intervention: -5.5 [IQR -14.0, -1.0]; control: -6.0 [IQR -10.0, -2.0]) was similar between study arms. There was no significant difference in mean percent change in the Reasons for Quitting scale score (intervention: 6.3 [95% confidence interval = -2.2% to 14.8%]; control: -3.6 [95% confidence interval = -9.2% to 2.1%]). A majority (n = 32, 91%) of participants liked having COach2Quit to help them quit smoking.

CONCLUSIONS

There were no significant differences in smoking cessation, smoking reduction, and motivation to quit between study arms. However, high satisfaction with the COach2Quit application indicates its feasibility and acceptability as a smoking cessation tool.

IMPLICATIONS

Smoking is the leading preventable cause of morbidity and mortality in the United States. Although counseling and pharmacotherapy are efficacious for smoking cessation, they are not easily accessible or desirable to all smokers, highlighting the need for identifying other interventions. There is evidence for the efficacy of mobile phone-based messaging support for smoking cessation. However, there is limited research on the efficacy of biomarker feedback, much less interventions that combine these two approaches. This research contributes to filling this gap and identifying novel interventions to facilitate smoking cessation.

Prevalence and Correlates of Snuff Use, and its Association With Tuberculosis, Among Women Living With HIV in South Africa

INTRODUCTION

A higher proportion of people living with HIV (PLWH) smoke compared to the general population, but little information exists about the prevalence and correlates of smokeless tobacco use among PLWH. In South Africa, dry powdered tobacco is inhaled nasally as snuff.

METHODS

A cross-sectional survey among PLWH attending three HIV clinics was conducted. Snuff use was assessed via self-report and urine cotinine.

RESULTS

Given the low (3%) prevalence of snuff use among men, analysis was restricted to n = 606 nonsmoking women living with HIV. Half (n = 298, 49%) were snuff users, the majority of whom (n = 244, 84%) had a positive urine cotinine test. In adjusted analysis, snuff use was negatively associated with higher education (relative risk [RR] 0.55; 95% confidence interval [CI]: 0.39, 0.77) and mobile phone ownership (RR 0.83; 95% CI: 0.71, 0.98), and positively associated with ever having tuberculosis (TB) (RR 1.22; 95% CI: 1.03, 1.45). In adjusted analysis, with current TB as the outcome, snuff use was marginally statistically significantly associated with a twofold increase in odds of a current TB diagnosis (odds ratio [OR] 1.99; 95% CI: 0.98, 4.15).

DISCUSSION

A high proportion of nonsmoking South African women living with HIV use snuff, which was a risk factor for TB. Additional research is needed to understand the relationship between snuff, TB, and other potential health risks.

IMPLICATIONS

PLWH have a higher prevalence of smoking than their seronegative peers, but there is a paucity of research on smokeless tobacco use in this population, especially in low-resource settings. TB is the leading cause of death among PLWH, and with improvements to HIV treatment and care, PLWH are at greater risk of tobacco-related diseases. We report an extremely high prevalence of snuff use among women living with HIV in South Africa. Further, in this population snuff use is positively associated with ever having a TB diagnosis, as well as currently having TB.

Mobile phone access and comfort: implications for HIV and tuberculosis care in India and South Africa

SETTING: India and South Africa shoulder the greatest burden of tuberculosis (TB) and human immunodeficiency virus (HIV) infection respectively, but care retention is suboptimal.OBJECTIVE: We conducted a study in Pune, India, and Matlosana, South Africa, 1) to identify the factors associated with mobile phone access and comfort of use, 2) to assess access patterns.DESIGN: A cross-sectional study assessed mobile phone access, and comfort; a longitudinal study assessed access patterns.RESULTS: We enrolled 261 participants: 136 in India and 125 in South Africa. Between 1 week and 6 months, participant contact decreased from 90% (n = 122) to 57% (n = 75) in India and from 93% (n = 116) to 70% (n = 88) in South Africa. In the latter, a reason for a clinic visit for HIV management was associated with 63% lower odds of contact than other priorities (e.g., diabetes mellitus, maternal health, TB). In India, 57% (n = 78) reported discomfort with texting; discomfort was higher in the unemployed (adjusted OR [aOR] 4.97, 95%CI 1.12-22.09) and those aged ≥35 years (aOR 1.10, 95%CI 1.04-1.16) participants, but lower in those with higher education (aOR 0.04, 95% CI 0.01-1.14). In South Africa, 91% (n = 114) reported comfort with texting.CONCLUSION: Mobile phone contact was poor at 6 months. While mHealth could transform TB-HIV care, alternative approaches may be needed for certain subpopulations.

Promoting Tuberculosis Preventive Therapy for People Living with HIV in South Africa: Interventions Hindered by Complicated Clinical Guidelines and Imbalanced Patient-Provider Dynamics

Isoniazid preventive therapy (IPT) reduces the risk of active tuberculosis among people living with HIV, but implementation of IPT in South Africa and elsewhere remains slow. The objective of this study was to examine both nurse perceptions of clinical mentorship and patient perceptions of in-queue health education for promoting IPT uptake in Potchefstroom, South Africa. We measured adoption, fidelity, acceptability, and sustainability of the interventions using both quantitative and qualitative methods. Adoption, fidelity, and acceptability of the interventions were moderately high. However, nurses believed they could not sustain their increased prescriptions of IPT, and though many patients intended to ask nurses about IPT, few did. Most patients attributed their behavior to an imbalance of patient-provider power. National IPT guidelines should be unambiguous and easily implemented after minimal training on patient eligibility and appropriate medication durations, nurse-patient dynamics should empower the patient, and district-level support and monitoring should be implemented.

Priorities among HIV-positive individuals for tuberculosis preventive therapies

BACKGROUND: There has been slow uptake of isoniazid preventive therapy (IPT) among people living with HIV (PLWH).METHODS: We surveyed adults recently diagnosed with HIV in 14 South African primary health clinics. Based on the literature and qualitative interviews, sixteen potential barriers and facilitators related to preventive therapy among PLWH were selected. Best-worst scaling (BWS) was used to quantify the relative importance of the attributes. BWS scores were calculated based on the frequency of participants' selecting each attribute as the best or worst among six options (across multiple choice sets) and rescaled from 0 (always selected as worst) to 100 (always selected as best) and compared by currently receiving IPT or not.RESULTS: Among 342 patients surveyed, 33% (n = 114) were currently taking IPT. Having the same standard of life as someone without HIV was most highly prioritized (BWS score = 67.3, SE = 0.6), followed by trust in healthcare providers (score, 66.3 ± 0.6). Poor standard of care in public clinics (score, 30.6 ± 0.6) and side effects of medications (score, 33.7 ± 0.6) were least prioritized. BWS scores differed by IPT status for few attributes, but overall ranking was similar (spearman's rho = 0.9).CONCLUSION: Perceived benefits of preventive therapy were high among PLWH. IPT prescription by healthcare providers should be encouraged to enhance IPT uptake among PLWH.

Prevalence and risk factors for latent tuberculosis infection among household contacts of index cases in two South African provinces: Analysis of baseline data from a cluster-randomised trial

INTRODUCTION

Household contacts of patients with active pulmonary tuberculosis (TB) often have latent TB infection, and are at risk of progression to disease. We set out to investigate whether index TB case HIV status was linked to a higher probability of latent TB infection among household contacts.

MATERIALS AND METHODS

Data were collected prospectively from participants in the intervention arm of a household cluster-randomised trial in two South Africa provinces (Mangaung, Free State, and Capricorn, Limpopo). In intervention group households, TB contacts underwent HIV testing and tuberculin skin testing (TST). TST induration was estimated at two cut-offs (≥5mm, ≥10mm). Multilevel Bayesian regression models estimated posterior distributions of the percentage of household contacts with TST induration ≥5mm and ≥10mm by age group, and compared the odds of latent TB infection by key risk factors including HIV status index case age and study province.

RESULTS

A total of 2,985 household contacts of 924 index cases were assessed, with most 2,725 (91.3%) undergoing TST. HIV prevalence in household contacts was 14% and 10% in Mangaung and Capricorn respectively. Overall, 16.8% (458/2,725) had TST induration of ≥5mm and 13.1% (359/2,725) ≥10mm. In Mangaung, children aged 0-4 years had a high TST positivity prevalence compared to their peers in Capricorn (22.0% vs. 7.6%, and 20.5% vs. 2.3%, using TST thresholds of ≥5mm and ≥10mm respectively). Compared to contacts from Capricorn, household contacts living in Mangaung were more likely to have TST induration ≥5mm (odds ratio [OR]: 3.08, 95% credibility interval [CI]: 2.13-4.58) and ≥10mm (OR: 4.52, 95% CI: 3.03-6.97). There was a 90% and 92% posterior probability that the odds of TST induration ≥5mm (OR: 0.79, 95% CI: 0.56-1.14) and ≥10mm (OR: 0.77, 95% CI: 0.53-1.10) respectively were lower in household contacts of HIV-positive compared to HIV-negative index cases.

CONCLUSIONS

High TST induration positivity, especially among young children and people living in Mangaung indicates considerable TB transmission despite high antiretroviral therapy coverage. Household contact of HIV-positive index TB cases were less likely to have evidence of latent TB infection than contacts of HIV-negative index cases.

Diabetes mellitus and tuberculosis in Korean adults: impact on tuberculosis incidence, recurrence and mortality

<sec id="st1"> <title>SETTING</title> The prevalence of diabetes mellitus (DM) worldwide is increasing markedly, and many countries with rising rates also have a high incidence rate of tuberculosis (TB). </sec> <sec id="st2"> <title>OBJECTIVE</title> To investigate the relationships of fasting serum glucose (FSG) and DM with TB incidence, recurrence and mortality risk in a prospective cohort study in South Korea. </sec> <sec id="st3"> <title>DESIGN</title> Our study comprised 1 267 564 Koreans who received health insurance from the National Health Insurance System, had an initial medical evaluation between 1997 and 2000 and were prospectively followed biennially. </sec> <sec id="st4"> <title>RESULTS</title> Participants with DM had a higher risk for incident TB (hazard ratio [HR] 1.81, 95%CI 1.71-1.91 in males, HR 1.33; 95%CI 1.20-1.47 in females) than those without DM. There was a strong positive trend for TB risk with rising FSG among males. The risk for recurrent TB among those with previous TB was significantly higher in males (HR 1.58, 95%CI 1.43-1.75) and in females with DM (HR 1.38, 95%CI 1.08-1.76). The increased risk of death from TB during follow-up was also significant in men (HR 1.91, 95%CI 1.87-1.95) and in women (HR 1.71, 95%CI 1.65-1.77). </sec> <sec id="st5"> <title>CONCLUSIONS</title> A diagnosis of DM is a risk factor for TB, TB recurrence and death from TB. Screening for TB should be considered among people living with DM in Korea, particularly those with severe DM. </sec>.

Respiratory health status is associated with treatment outcomes in pulmonary tuberculosis

<sec id="st1"> <title>BACKGROUND</title> The association between respiratory impairment and tuberculosis (TB) treatment outcomes is not clear. </sec> <sec id="st2"> <title>METHODS</title> We prospectively evaluated respiratory health status, measured using the Saint George's Respiratory Questionnaire (SGRQ), in a cohort of new adult pulmonary TB cases during and up to 18 months following treatment in India. Associations between total SGRQ scores and poor treatment outcomes of failure, recurrence and all-cause death were measured using multivariable Poisson regression. </sec> <sec id="st3"> <title>RESULTS</title> We enrolled 455 participants contributing 619 person-years at risk; 39 failed treatment, 23 had recurrence and 16 died. The median age was 38 years (interquartile range 26-49); 147 (32%) ever smoked. SGRQ scores at treatment initiation were predictive of death during treatment (14% higher risk per 4-point increase in baseline SGRQ scores, 95%CI 2-28, P = 0.01). Improvement in SGRQ scores during treatment was associated with a lower risk of failure (1% lower risk for every per cent improvement during treatment, 95%CI 1-2, P = 0.05). Clinically relevant worsening in SGRQ scores following successful treatment was associated with a higher risk of recurrence (15% higher risk per 4-point increase scores, 95%CI 4-27, P = 0.004). </sec> <sec id="st4"> <title>CONCLUSION</title> Impaired respiratory health status was associated with poor TB treatment outcomes. The SGRQ may be used to monitor treatment response and predict the risk of death in pulmonary TB. </sec>.

CD4+ cell count stratification to guide tuberculosis preventive therapy for people living with HIV

OBJECTIVES

In 2018, Brazilian guidelines changed to recommend tuberculosis (TB) preventive therapy for all people with HIV and a CD4 cell count 350 cells/μl or less, but only for those with a positive tuberculin skin test (TST) if CD4 cell count is than 350 cells/μl. We determined the potential effectiveness of CD4-based guidelines for TB testing and preventive therapy.

DESIGN

Secondary analysis of the stepped-wedge, cluster-randomized THRio trial for isoniazid preventive therapy (IPT).

METHODS

We analyzed data from 4114 newly registered patients with HIV in 29 clinics followed until TB diagnosis, death, or administrative censoring. We compared incidence rates of TB and TB/death between CD4, TST, IPT, and antiretroviral therapy categories.

RESULTS

Initial CD4 cell count was 350 cells/μl or less in 2138 (52%) and more than 350 cells/μl in 1976 (48%) patients. TST was performed for 2922 (71%), of whom 657 (16%) were TST-positive [278 (13%) CD4 ≤ 350 vs. 379 (19%) CD4 > 350]. A total of 619 (15%) received IPT and 2806 (68%) received antiretroviral therapy. For patients with CD4 cell count 350 cells/μl or less who did not receive IPT, the incidence rate of TB was 1.79/100 person-years (pys) and TB/death was 3.89/100 pys. For patients with CD4 cell count more than 350 who did not receive IPT, the incidence rates of TB and TB/death were 0.57/100 and 1.49/100 pys for TST-negatives, and 1.05/100 and 1.64/100 pys for TST-unknowns.

CONCLUSION

TB incidence was high among all patients who did not receive IPT, including those with CD4 cell count more than 350 cells/μl and negative or unknown TST results. TB preventive therapy should be provided to all people living with HIV in medium burden settings, regardless of CD4 cell count and TST status.

Seventy Years of Tuberculosis Prevention: Efficacy, Effectiveness, Toxicity, Durability, and Duration

Tuberculosis (TB) has been a leading infectious cause of death worldwide for much of human history, with 1.6 million deaths estimated in 2017. The Department of Epidemiology at the Johns Hopkins Bloomberg School of Public Health has played an important role in understanding and responding to TB, and it has made particularly substantial contributions to prevention of TB with chemoprophylaxis. TB preventive therapy is highly efficacious in the prevention of TB disease, yet it remains underutilized by TB programs worldwide despite strong evidence to support its use in high-risk groups, such as people living with HIV and household contacts, including those under 5 years of age. We review the evidence for TB preventive therapy and discuss the future of TB prevention.

Cost-effectiveness of QuantiFERON-TB Gold In-Tube versus tuberculin skin test for diagnosis and treatment of Latent Tuberculosis Infection in primary health care workers in Brazil

Objectives

The goal of this study was to perform a cost-effectiveness analysis from the public health system perspective, comparing five strategies for Latent Tuberculosis Infection (LTBI) diagnosis in primary health care workers in Brazil.

Design

Analytical model for decision making, characterized by cost-effectiveness analysis.

Setting

Primary Care Level, considering primary health care workers in Brazil.

Participants

An analytical model for decision making, characterized by a tree of probabilities of events, was developed considering a hypothetical cohort of 10,000 primary health care workers, using the software TreeAge Pro^™ 2013 to simulate the clinical and economic impacts of new diagnostic technology (QuantiFERON^®-TB Gold in-Tube) versus the traditional tuberculin skin test.

Methods

This model simulated five diagnostic strategies for LTBI in primary health care workers (HCW) in Brazil: tuberculin skin testing using ≥5 mm cut-off, tuberculin skin testing ≥10 mm cut-off, QuantiFERON^®-TB Gold in-Tube, tuberculin skin testing using ≥5 mm cut-off confirmed by QuantiFERON^®-TB Gold In-Tube if TST positive, tuberculin skin testing using ≥10 mm cut-off confirmed by QuantiFERON^®-TB Gold In-Tube if TST positive.

Primary and secondary outcome measures

The outcome measures are the number of individuals correctly classified by the test and the number of Tuberculosis cases avoided.

Results

The most cost-effective strategy was the tuberculin skin test considering ≥10mm cut-off. The isolated use of the QuantiFERON^®-TB Gold In-Tube revealed the strategy of lower efficiency with incremental cost-effectiveness ratio (ICER) of US$ 146.05 for each HCW correctly classified by the test.

Conclusions

The tuberculin skin test using ≥10 mm cut-off was the most cost-effective strategy in the diagnosis of Latent Tuberculosis Infection in primary health care works in Brazil.

Lipid mediators of inflammation and Resolution in individuals with tuberculosis and tuberculosis-Diabetes

Individuals with concurrent tuberculosis (TB) and Type 2 diabetes (DM) have a higher risk of adverse outcomes. To better understand potential immunological differences, we utilized a comprehensive panel to characterize pro-inflammatory and pro-resolving (i.e., mediators involved in the resolution of inflammation) lipid mediators in individuals with TB and TB-DM. A nested cross-sectional study of 40 individuals (20 newly diagnosed DM and 20 without DM) was conducted within a cohort of individuals with active drug-susceptible treatment-naïve pulmonary TB. Lipid mediators were quantified in serum samples through lipid mediator profiling. We conducted correlation-based analysis of these mediators. Overall, the arachidonic acid-derived leukotriene and prostaglandin families were the most abundant pro-inflammatory lipid mediators, while lipoxins and maresins families were the most abundant pro-resolving lipid mediators in individuals with TB and TB-DM. Individuals with TB-DM had increased correlations and connectivity with both pro-inflammatory and pro-resolving lipid mediators compared to those with TB alone. We identified the most abundant lipid mediator metabolomes in circulation among individuals with TB and TB-DM; in addition, our data shows a substantial number of significant correlations between both pro-inflammatory and pro-resolving lipid mediators in individuals with TB-DM, delineating a molecular balance that potentially defines this comorbidity.

Transmission of Mycobacterium tuberculosis From Patients Who Are Nucleic Acid Amplification Test Negative

Background

Among adults with signs and symptoms of pulmonary tuberculosis (TB), recognition of transmissible TB has implications for airborne infection isolation and public health activities. Sputum smear-negative TB patients account for around one-fifth of tuberculosis transmission. The tuberculosis transmission risk of TB patients with negative results on nucleic acid amplification test (NAAT) of respiratory specimens has not been established. We sought to estimate the tuberculosis transmission risk of NAAT-negative TB patients.

Methods

We retrospectively reviewed Maryland TB program data collected from 2004 to 2009, during which time NAAT using the Mycobacterium Tuberculosis Direct Test (MTD) was performed routinely. Patients with sputum Mycobacterium tuberculosis (M.tb) isolates having matching genotypes were assigned to clusters. Transmission sequence was approximated by collection order of individuals' first culture-positive specimens. Minimum transmission risks of NAAT (MTD)-negative TB patients and of smear-negative TB patients were estimated based on individuals' positions within clusters.

Results

Among 809 patients with culture-confirmed TB, M.tb genotypes were available for 782 (96.7%). For NAA-negative TB patients, the minimum transmission risk estimate was 5.1% (95% CI 0-11.4). For smear-negative TB patients, the minimum transmission risk estimate was 11.2% (95% CI 7.2-15.3).

Conclusions

Minimum transmission risk of NAAT-negative TB patients was lower than that of smear-negative TB patients. However, transmission risk of NAA-negative TB patients appears to not be negligible.