Attributable is preventable: Corrected and revised estimates of population attributable fraction of TB related to undernutrition in 30 high TB burden countries

Anthropometric growth trajectories of children presenting with presumptive pulmonary TB

BACKGROUND

This study assessed growth trajectories in children presenting with presumptive pulmonary TB (PTB).

METHODS

This sub-study of the Umoya TB diagnostic study was conducted in South Africa from November 2017 until November 2021. Children (0-13 years) with presumptive PTB were recruited from and followed up for 12 months. Anthropometric measurements of children with TB, symptomatic controls (TB excluded), and healthy controls were taken at baseline and follow-up (2, 8, 16, 24 and 52 weeks). Changes in weight-for-age Z-score (WAZ), height-for-age Z-score (HAZ) and body mass index for age (BAZ) over time were assessed using multivariable mixed-effect linear regression adjusted for confounders.

RESULTS

Of the 372 children included in the analyses (median age: 2 years, IQR 1-4), 153 children had TB, 168 were symptomatic and 51 were healthy controls. Median WAZ was similar between groups; however, more children with TB were underweight than symptomatic and healthy controls. WAZ increased over time for children with TB. Median HAZ of children with TB (-1.34, IQR -2.17 to -0.21) was lower compared to symptomatic (-1.06, IQR -1.90 to -0.10) and healthy controls (-0.74, IQR -1.26 to -0.03; P = 0.0037). There was no significant change over time for HAZ.

CONCLUSION

To improve the long-term outcomes of TB and other illnesses, the overall nutrition of children needs to be improved.

Estimating the epidemiological and economic impact of providing nutritional care for tuberculosis-affected households across India: a modelling study

BACKGROUND

Approximately 20% of global tuberculosis incidence is attributable to undernutrition, increasing to more than a third in India. Targeting nutritional interventions to tuberculosis-affected households is a policy priority, but understanding of epidemiological and economic impacts is limited. We aimed to estimate the population-level epidemiological and economic effect of such an intervention.

METHODS

We used a previously published, age-stratified, compartmental transmission model of tuberculosis in India, and incorporated explicit BMI strata linked to disease progression and treatment outcomes. We used results from a recent trial of an intervention in which nutritional support in the form of food baskets was provided to people initiating tuberculosis treatment and to their household contacts (1200 kcal for patients and 750 kcal for contacts) to inform estimates of the impact and costs of nutritional support. We estimated the numbers of cases of tuberculosis disease and deaths due to tuberculosis disease that could be averted from 2023 to 2035 under the intervention scenario.

FINDINGS

Compared with a baseline with no nutritional intervention, at 50% coverage of adults on tuberculosis treatment and their households (around 23% of households affected by incident tuberculosis in India), providing the nutritional support intervention could prevent 361 200 (95% uncertainty interval 318 000-437 700) tuberculosis deaths and 880 700 (802 700-974 900) disease episodes from 2023 to 2035. This would be equivalent to averting approximately 4·6% (4·2-5·5) tuberculosis deaths and 2·2% (2·1-2·4) tuberculosis episodes. The additional health system cost would be US$1349 million (1221-1492), with an incremental cost-effectiveness ratio of $167 (147-187) per disability-adjusted life-year averted. The median number of households needed to treat to prevent one tuberculosis death was 24·4 and to prevent one tuberculosis case was 10·0.

INTERPRETATION

A nutritional intervention for tuberculosis-affected households could avert a substantial amount of tuberculosis disease and death in India, and would be highly likely to be cost-effective on the basis of the tuberculosis-specific benefits alone.

FUNDING

None.

TRANSLATIONS

For the Bangla and Hindi translations of the abstract see Supplementary Materials section.

Ni-kshay Poshan Yojana: receipt and utilization among persons with TB notified under the National TB Elimination Program in India, 2022

BACKGROUND

Ni-kshay Poshan Yojana (NPY), a direct benefit transfer scheme under the National Tuberculosis Elimination Program (NTEP) in India, provides a monthly benefit of INR500 for nutritional support of persons with TB (PwTB).

OBJECTIVES

To determine the proportion of PwTB receiving atleast one NPY instalment and pattern of utilisation; to ascertain factors associated with NPY non-receipt and association of NPY receipt with TB treatment outcome.

METHODS

In our cross-sectional study, we used multi-stage sampling to select PwTB whose treatment outcome was declared between May 2022 and February 2023. A cluster-adjusted, generalized linear model was used to identify factors associated with the non-receipt of NPY and determine association between NPY receipt and TB treatment outcome.

RESULTS

Among 3201 PwTB, 2888 (92.7%; 95% CI 89.8%, 94.8%) had received at least one NPY instalment, and 1903 (64.2%; 95% CI 58.9%, 69.2%) self-reported receipt of benefit. The median (IQR) time to receipt of first instalment was 105 (60,174) days. Non-receipt was significantly higher among PwTB from states with low TB score (aPR = 2.34; 95%CI 1.51, 3.62), who do not have bank account (aPR = 2.48; 95%CI 1.93, 3.19) and with unknown/missing diabetic status (aPR = 1.69; 95%CI 1.11, 2.55). Unfavorable treatment outcomes were associated with non-receipt of NPY (aPR 4.93; 95%CI 3.61,6.75) after adjusting for potential confounders.

CONCLUSION

Majority of the PwTB received atleast one NPY instalment, but they experience significant delays. Most of the recipients utilised NPY for nutrition. Longitudinal follow-up studies are required to study the impact of NPY on treatment outcomes.

Subnational tuberculosis burden estimation for Pakistan

Global tuberculosis (TB) burden estimates are aggregated at the national level, despite the likelihood of uneven distribution across and within regions in the same country. Subnational estimates are crucial to producing informed policies and informing budget allocation at more granular levels. In collaboration with the National TB Programme (NTP), we applied a simple and transparent tool to estimate the subnational TB burden in Pakistan. We tailored the SUBnational Burden Estimation for TB (SUBsET) tool to account for the district-level hierarchy of Pakistan. Districts were assigned weighted scores based on population size, level of urbanisation, households with one room, and food insecurity levels. Using the 2022 national TB incidence estimate, we first allocated the burden across administrative units based on data from the 2010-11 TB prevalence survey and subsequently refined this distribution to reflect weighted scores specific to each district. The estimated TB incidence was compared with pulmonary TB notifications to calculate the case detection rate (CDR) for each district. Utilising the updated SUBsET model, we assigned weight scores to 150 districts spanning seven provinces/regions in Pakistan. The estimated TB incidence varied significantly, ranging from 110 (95%CI: 80-145) to 462 (95%CI: 337-607) per 100,000 inhabitants per year. The provinces bearing the highest burden was Sindh (292; 95%CI: 213-384), followed by Khyber Pakhtunkhwa (269; 95%CI: 196-354) and Punjab (243; 95%CI: 177-320). The CDR was below 70% in three-quarters of the districts and over-reporting (>100%) was observed in 10 districts, primarily within Punjab, which suggests that individuals with TB may be crossing district lines to access care. The application of the SUBsET tool through active collaboration with the NTP revealed high heterogeneity in subnational TB incidence in Pakistan, urging a more granular and tailored approach to TB prevention and care. This approach ensured transparency and acceptance of the findings for wider in-country dissemination.

Food Insecurity at Tuberculosis Treatment Initiation Is Associated With Clinical Outcomes in Rural Haiti: A Prospective Cohort Study

BACKGROUND

Tuberculosis is a leading cause of death worldwide, and food insecurity is known to negatively influence health outcomes through multiple pathways. Few studies have interrogated the relationship between food insecurity and tuberculosis outcomes, particularly independent of nutrition.

METHODS

We conducted a prospective cohort study of adults initiating first-line treatment for clinically suspected or microbiologically confirmed drug-sensitive tuberculosis at a rural referral center in Haiti. We administered a baseline questionnaire, collected clinical data, and analyzed laboratory samples. We used logistic regression models to estimate the relationship between household food insecurity (Household Hunger Scale) and treatment failure or death. We accounted for exclusion of patients lost to follow-up using inverse probability of censoring weighting and adjusted for measured confounders and nutritional status using inverse probability of treatment weighting.

RESULTS

We enrolled 257 participants (37% female) between May 2020 and March 2023 with a median age (interquartile range) of 35 (25-45) years. Of these, 105 (41%) had no hunger in the household, 104 (40%) had moderate hunger in the household, and 48 (19%) had severe hunger in the household. Eleven participants (4%) died, and 6 (3%) had treatment failure. After adjustment, food insecurity was significantly associated with subsequent treatment failure or death (odds ratio 5.78 [95% confidence interval, 1.20-27.8]; P = .03).

CONCLUSIONS

Household food insecurity at tuberculosis treatment initiation was significantly associated with death or treatment failure after accounting for loss to follow-up, measured confounders, and nutritional status. In addition to the known importance of undernutrition, our findings indicate that food insecurity independently affects tuberculosis treatment outcomes in Haiti.

Undernutrition as a risk factor for tuberculosis disease

BACKGROUND

Tuberculosis (TB) is a leading cause of mortality due to an infectious disease, with an estimated 1.6 million deaths due to TB in 2022. Approximately 25% of the global population has TB infection, giving rise to 10.6 million episodes of TB disease in 2022. Undernutrition is a key risk factor for TB and was linked to an estimated 2.2 million TB episodes in 2022, as outlined in the World Health Organization (WHO) Global Tuberculosis Report.

OBJECTIVES

To determine the prognostic value of undernutrition in the general population of adults, adolescents, and children for predicting tuberculosis disease over any time period.

SEARCH METHODS

We searched the literature databases MEDLINE (via PubMed) and WHO Global Index Medicus, as well as the WHO International Clinical Trials Registry Platform (ICTRP) on 3 May 2023 (date of last search for all databases). We placed no restrictions on the language of publication.

SELECTION CRITERIA

We included retrospective and prospective cohort studies, irrespective of publication status or language. The target population comprised adults, adolescents, and children from diverse settings, encompassing outpatient and inpatient cohorts, with varying comorbidities and risk of exposure to tuberculosis.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methodology and the Quality In Prognosis Studies (QUIPS) tool to assess the risk of bias of the studies. Prognostic factors included undernutrition, defined as wasting, stunting, and underweight, with specific measures such as body mass index (BMI) less than two standard deviations below the median for children and adolescents and low BMI scores (< 18.5) for adults and adolescents. Prognostication occurred at enrolment/baseline. The primary outcome was the incidence of TB disease. The secondary outcome was recurrent TB disease. We performed a random-effects meta-analysis for the adjusted hazard ratios (HR), risk ratios (RR), or odds ratios (OR), employing the restricted maximum likelihood estimation. We rated the certainty of the evidence using the GRADE approach.

MAIN RESULTS

We included 51 cohort studies with over 27 million participants from the six WHO regions. Sixteen large population-based studies were conducted in China, Singapore, South Korea, and the USA, and 25 studies focused on people living with HIV, which were mainly conducted in the African region. Most studies were in adults, four in children, and three in children and adults. Undernutrition as an exposure was usually defined according to standard criteria; however, the diagnosis of TB did not include a confirmatory culture or molecular diagnosis using a WHO-approved rapid diagnostic test in eight studies. The median follow-up time was 3.5 years, and the studies primarily reported an adjusted hazard ratio from a multivariable Cox-proportional hazard model. Hazard ratios (HR) The HR estimates represent the highest certainty of the evidence, explored through sensitivity analyses and excluding studies at high risk of bias. We present 95% confidence intervals (CI) and prediction intervals, which present between-study heterogeneity represented in a measurement of the variability of effect sizes (i.e. the interval within which the effect size of a new study would fall considering the same population of studies included in the meta-analysis). Undernutrition may increase the risk of TB disease (HR 2.23, 95% CI 1.83 to 2.72; prediction interval 0.98 to 5.05; 23 studies; 2,883,266 participants). The certainty of the evidence is low due to a moderate risk of bias across studies and inconsistency. When stratified by follow-up time, the results are more consistent across < 10 years follow-up (HR 2.02, 95% CI 1.74 to 2.34; prediction interval 1.20 to 3.39; 22 studies; 2,869,077 participants). This results in a moderate certainty of evidence due to a moderate risk of bias across studies. However, at 10 or more years of follow-up, we found only one study with a wider CI and higher HR (HR 12.43, 95% CI 5.74 to 26.91; 14,189 participants). The certainty of the evidence is low due to the moderate risk of bias and indirectness. Odds ratio (OR) Undernutrition may increase the odds of TB disease, but the results are uncertain (OR 1.56, 95% CI 1.13 to 2.17; prediction interval 0.61 to 3.99; 8 studies; 173,497 participants). Stratification by follow-up was not possible as all studies had a follow-up of < 10 years. The certainty of the evidence is very low due to the high risk of bias and inconsistency. Contour-enhanced funnel plots were not reported due to the few studies included. Risk ratio (RR) Undernutrition may increase the risk of TB disease (RR 1.96, 95% CI 1.73 to 2.21; prediction interval 1.50 to 2.56; 4 studies; 1,475,867 participants). Stratification by follow-up was not possible as all studies had a follow-up of < 10 years. The certainty of the evidence is low due to the high risk of bias. Contour-enhanced funnel plots were not reported due to the few studies included.

AUTHORS' CONCLUSIONS

Undernutrition probably increases the risk of TB two-fold in the short term (< 10 years) and may also increase the risk in the long term (> 10 years). Policies targeted towards the reduction of the burden of undernutrition are not only needed to alleviate human suffering due to undernutrition and its many adverse consequences, but are also an important part of the critical measures for ending the TB epidemic by 2030. Large population-based cohorts, including those derived from high-quality national registries of exposures (undernutrition) and outcomes (TB disease), are needed to provide high-certainty estimates of this risk across different settings and populations, including low and middle-income countries from different WHO regions. Moreover, studies including children and adolescents and state-of-the-art methods for diagnosing TB would provide more up-to-date information relevant to practice and policy.

FUNDING

World Health Organization (203256442).

REGISTRATION

PROSPERO registration: CRD42023408807 Protocol: https://doi.org/10.1002/14651858.CD015890.

Body Mass Index a Forecast of Sputum Culture Conversion Among Drug-Resistant Tuberculosis Patients

Background Drug-resistant tuberculosis is a major health issue around the world. The time it takes to find a sputum-positive patient is a major risk factor for the spread of tuberculosis, and many things can indicate a longer time to culture conversion. Also, there is strong proof that poor nutrition is linked to infectious diseases. So, this study aimed to look into the link between a person's body mass index (BMI) and the change of a sputum culture within three months in people who have rifampicin-resistant (RR)/multidrug-resistant (MDR)-tuberculosis (TB) kept on a bedaquiline-based regimen. Materials and methods The Department of Respiratory Medicine at King George's Medical University, Lucknow, hosted an observational, analytical, prospective, single-center study from May 2020 to April 2021. The study included 105 people who had been identified with RR/MDR-TB and were on an optimized background regimen that included a bedaquiline-based regimen. The result we were interested in was sputum culture conversion within three months, and we looked at how BMI related to that outcome. Analytical analyses utilized Pearson's chi-square test for categorical variables and the t-test for continuous variables. Differences with a P-value of <0.05 were considered significant. SPSS software (version 18.0, IBM Corp., Armonk, NY, USA) was used for all analyses, with missing data not replaced or credited. Results A total of 105 people who met the inclusion and exclusion criteria were analyzed. The patients had a mean age of 33.34 years and were mostly male 61 (58%). Fifty-eight (58; 55%) patients lived in rural areas. Most patients had fever 77 (73%), cough 72 (69%), and weight loss 66 (63%). Sixty-nine (69; 66%) patients had a history of TB. Fifty-seven patients had a BMI of <18.5 kg/m2, and 48 patients had with BMI of ≥18.5. At the end of the study, 75/105 patients converted their sputum culture. Of the 105 patients, 57 (54%) had a low BMI (less than 18.5 kg/m2). Among the 57 patients with a BMI of <18.5 kg/m2, only 28 (46%) achieved sputum culture conversion after 3 months while 29 (60%) of 48 with BMI ≥18.5 achieved sputum culture conversion after 3 months. Among the patients with a BMI <18.5, 15/57 (26%) tested positive for sputum culture after three months. In patients with a BMI of ≥18.5, only 4/48 (8%) patients tested positive for sputum culture after three months. Conclusion In patients with drug-resistant tuberculosis, low BMI (<18.5 kg/m2) was an independent risk factor for failing to convert sputum cultures within three months.

Food Insecurity and Undernutrition Are Associated With Distinct Immunologic Profiles in People With Tuberculosis and Advanced HIV Starting Antiretroviral Therapy

BACKGROUND

Food insecurity and undernutrition are related but distinct concepts contributing to poor HIV and tuberculosis outcomes. Pathways linking them with immunologic profile, which may relate to clinical outcomes, remain understudied.

METHODS

We analyzed data from a cohort study of 165 antiretroviral therapy (ART)-naïve adults with advanced HIV and newly diagnosed tuberculosis in Botswana from 2009 to 2013. Twenty-nine plasma biomarkers were measured pre-ART and 4 weeks post-ART initiation. We used principal components analysis (PCA) and multivariable linear regression models to assess relationships between immunological profiles and food insecurity (based on the Household Food Insecurity Access Scale), undernutrition (body mass index <18.5 kg/m 2 ), and clinical outcomes.

RESULTS

PCA identified 5 principal components with eigenvalues >1. After adjustment, food insecurity was associated with PC3 pre-ART (0.19 per increased category of severity, 95% CI: 0.02 to 0.36) and post-ART (0.24, 95% CI: 0.07 to 0.41). PC3 was driven by higher levels of IFN-α, IFN-γ, interleukin (IL)-12p40, vascular endothelial growth factor, IL-1α, and IL-8 and decreased concentrations of IL-3. Undernutrition was associated with PC5 post-ART (0.49, 95% CI: 0.16 to 0.82). PC5 was driven by higher levels of IL-8, MIP-1α, IL-6, and IL-10 and decreased concentrations in IP-10 and IFN-α. Post-ART PC3 (4.3 percentage point increased risk per increased score of 1, 95% CI: 0.3 to 8.9) and post-ART PC5 (4.8, 95% CI: 0.6 to 8.9) were associated with death in adjusted models.

DISCUSSION

We identified 2 distinct immunologic profiles associated with food insecurity, undernutrition, and clinical outcomes in patients with advanced HIV and tuberculosis. Different pathophysiologic processes may link food insecurity and undernutrition with poor outcomes in this vulnerable patient population. Future studies should assess the impact of improving food access and intake on immune function and clinical outcomes.

Multidrug-resistant tuberculosis

Tuberculosis (TB) remains the foremost cause of death by an infectious disease globally. Multidrug-resistant or rifampicin-resistant TB (MDR/RR-TB; resistance to rifampicin and isoniazid, or rifampicin alone) is a burgeoning public health challenge in several parts of the world, and especially Eastern Europe, Russia, Asia and sub-Saharan Africa. Pre-extensively drug-resistant TB (pre-XDR-TB) refers to MDR/RR-TB that is also resistant to a fluoroquinolone, and extensively drug-resistant TB (XDR-TB) isolates are additionally resistant to other key drugs such as bedaquiline and/or linezolid. Collectively, these subgroups are referred to as drug-resistant TB (DR-TB). All forms of DR-TB can be as transmissible as rifampicin-susceptible TB; however, it is more difficult to diagnose, is associated with higher mortality and morbidity, and higher rates of post-TB lung damage. The various forms of DR-TB often consume >50% of national TB budgets despite comprising <5-10% of the total TB case-load. The past decade has seen a dramatic change in the DR-TB treatment landscape with the introduction of new diagnostics and therapeutic agents. However, there is limited guidance on understanding and managing various aspects of this complex entity, including the pathogenesis, transmission, diagnosis, management and prevention of MDR-TB and XDR-TB, especially at the primary care physician level.

Ending TB in South-East Asia: flagship priority and response transformation

Over the decades, the global tuberculosis (TB) response has evolved from sanatoria-based treatment to DOTS (Directly Observed Therapy Shortcourse) strategy and the more recent End TB Strategy. The WHO South-East Asia Region, which accounted for 45% of new TB patients and 50% of deaths globally in 2021, is pivotal to the global fight against TB. "Accelerate Efforts to End TB" by 2030 was adopted as a South-East Asia Regional Flagship Priority (RFP) in 2017. This article illustrates intensified and transformed approaches to address the disease burden following the adoption of RFP and new challenges that emerged during the COVID-19 pandemic. TB case notifications improved by 25% and treatment success rates improved by 6% between 2016 and 2019 due to interventions ranging from galvanising political commitments to empowering and engaging communities. Cumulative TB programme budget allocations in 2022 reached US$ 1.4 billion, about two and a half times the budget in 2016. An ambitious Regional Strategic Plan towards ending TB, 2021-2025, identifies priority interventions that will need investments of up to US$ 3 billion a year to fully implement them. Moving forward, countries in the Region need to leverage RFP and take up intensified, people-centred, holistic interventions for prevention, diagnosis, treatment and care of TB with commensurate investments and cross-ministerial and multi-sectoral coordination.

Geospatial Overlap of Undernutrition and Tuberculosis in Ethiopia

Undernutrition is a key driver of the global tuberculosis (TB) epidemic, yet there is limited understanding regarding the spatial overlap of both diseases. This study aimed to determine the geographical co-distribution and socio-climatic factors of undernutrition and TB in Ethiopia. Data on undernutrition were found from the Ethiopian Demographic and Health Survey (EDHS). Data on TB were obtained from the Ethiopia national TB prevalence survey. We applied a geostatistical model using a Bayesian framework to predict the prevalence of undernutrition and TB. Spatial overlap of undernutrition and TB prevalence was detected in the Afar and Somali regions. Population density was associated with the spatial distribution of TB [β: 0.008; 95% CrI: 0.001, 0.014], wasting [β: -0.017; 95% CrI: -0.032, -0.004], underweight [β: -0.02; 95% CrI: -0.031, -0.011], stunting [β: -0.012; 95% CrI: -0.017, -0.006], and adult undernutrition [β: -0.007; 95% CrI: -0.01, -0.005]. Distance to a health facility was associated with the spatial distribution of stunting [β: 0.269; 95% CrI: 0.08, 0.46] and adult undernutrition [β: 0.176; 95% CrI: 0.044, 0.308]. Healthcare access and demographic factors were associated with the spatial distribution of TB and undernutrition. Therefore, geographically targeted service integration may be more effective than nationwide service integration.

Malnutrition leads to increased inflammation and expression of tuberculosis risk signatures in recently exposed household contacts of pulmonary tuberculosis

Background

Most individuals exposed to Mycobacterium tuberculosis (Mtb) develop latent tuberculosis infection (LTBI) and remain at risk for progressing to active tuberculosis disease (TB). Malnutrition is an important risk factor driving progression from LTBI to TB. However, the performance of blood-based TB risk signatures in malnourished individuals with LTBI remains unexplored. The aim of this study was to determine if malnourished and control individuals had differences in gene expression, immune pathways and TB risk signatures.

Methods

We utilized data from 50 tuberculin skin test positive household contacts of persons with TB - 18 malnourished participants (body mass index [BMI] < 18.5 kg/m2) and 32 controls (individuals with BMI ≥ 18.5 kg/m2). Whole blood RNA-sequencing was conducted to identify differentially expressed genes (DEGs). Ingenuity Pathway Analysis was applied to the DEGs to identify top canonical pathways and gene regulators. Gene enrichment methods were then employed to score the performance of published gene signatures associated with progression from LTBI to TB.

Results

Malnourished individuals had increased activation of inflammatory pathways, including pathways involved in neutrophil activation, T-cell activation and proinflammatory IL-1 and IL-6 cytokine signaling. Consistent with known association of inflammatory pathway activation with progression to TB disease, we found significantly increased expression of the RISK4 (area under the curve [AUC] = 0.734) and PREDICT29 (AUC = 0.736) progression signatures in malnourished individuals.

Conclusion

Malnourished individuals display a peripheral immune response profile reflective of increased inflammation and a concomitant increased expression of risk signatures predicting progression to TB. With validation in prospective clinical cohorts, TB risk biomarkers have the potential to identify malnourished LTBI for targeted therapy.