Informing decision-making for universal access to quality tuberculosis diagnosis in India: an economic-epidemiological model

A Generalizable Decision-Making Framework for Selecting Onsite versus Send-out Clinical Laboratory Testing

BACKGROUND

Laboratory networks provide services through onsite testing or through specimen transport to higher-tier laboratories. This decision is based on the interplay of testing characteristics, treatment characteristics, and epidemiological characteristics.

OBJECTIVES

Our objective was to develop a generalizable model using the threshold approach to medical decision making to inform test placement decisions.

METHODS

We developed a decision model to compare the incremental utility of onsite versus send-out testing for clinical purposes. We then performed Monte Carlo simulations to identify the settings under which each strategy would be preferred. Tuberculosis was modeled as an exemplar.

RESULTS

The most important determinants of the decision to test onsite versus send-out were the clinical utility lost due to send-out testing delays and the accuracy decrement with onsite testing. When the sensitivity decrements of onsite testing were minimal, onsite testing tended to be preferred when send-out delays reduced clinical utility by >20%. By contrast, when onsite testing incurred large reductions in sensitivity, onsite testing tended to be preferred when utility lost due to delays was >50%. The relative cost of onsite versus send-out testing affected these thresholds, particularly when testing costs were >10% of treatment costs.

CONCLUSIONS

Decision makers can select onsite versus send-out testing in an evidence-based fashion using estimates of the percentage of clinical utility lost due to send-out delays and the relative accuracy of onsite versus send-out testing. This model is designed to be generalizable to a wide variety of use cases.

HIGHLIGHTS

The design of laboratory networks, including the decision to place diagnostic instruments at the point-of-care or at higher tiers as accessed through specimen transport, can be informed using the threshold approach to medical decision making.The most important determinants of the decision to test onsite versus send-out were the clinical utility lost due to send-out testing delays and the accuracy decrement with onsite testing.The threshold approach to medical decision making can be used to compare point-of-care testing accuracy decrements with the lost utility of treatment due to send-out testing delays.The relative cost of onsite versus send-out testing affected these thresholds, particularly when testing costs were >10% of treatment costs.

Newer TB diagnostics: An update

In recent years, nucleic-acid amplification tests (NAATs), which are highly specific and sensitive, have helped to transform the TB diagnostic landscape. According to the WHO 2021 Guidelines on Diagnostics, the NAATs used in TB diagnosis at the point of care (POC) include Xpert MTB/RIF a cartridge-based test manufactured by Cepheid, and Truenat a chip-based test manufactured by Molbio. Other POC tests that are expected to be implemented in near future include Xpert Omni and Xpert MTB/XDR. The use of line probe assay is involved at the level of reference labs for the detection of MTB and its resistance to first-line (Isoniazid and Rifampicin) and second-line (fluoroquinolones and second-line injectables) drugs. When the currently available NAATs detect mutations for drug resistance at a particular region of MTB sequence, the Whole genome sequencing (WGS) platform demonstrates the exceptional potential for reliable and comprehensive resistance prediction for MTB isolates, by multiple gene regions or whole genome sequence analysis allowing for accurate clinical decisions.

Multicomponent strategy with decentralised molecular testing for tuberculosis in Uganda: a cost and cost-effectiveness analysis

BACKGROUND

Decentralised molecular testing for tuberculosis could reduce missed diagnoses and losses to follow-up in high-burden settings. The aim of this study was to evaluate the cost and cost-effectiveness of the Xpert Performance Evaluation for Linkage to Tuberculosis Care (XPEL-TB) study strategy, a multicomponent strategy including decentralised molecular testing for tuberculosis, in Uganda.

METHODS

We conducted a costing and cost-effectiveness analysis nested in a pragmatic cluster-randomised trial of onsite (decentralised) versus hub-and-spoke (centralised) testing for tuberculosis with Xpert MTB/RIF Ultra (Xpert) in 20 community health centres in Uganda. We collected empirical data on the cost of the XPEL-TB strategy (decentralised Xpert testing, workflow redesign, and performance feedback) and routine tuberculosis testing (onsite smear microscopy with specimen transport for centralised Xpert testing) from the health system perspective. Time-and-motion studies were performed to estimate activity-based service costs. Cost-effectiveness was assessed as the incremental cost (2019 US$) per tuberculosis diagnosis and per 14-day treatment initiation.

FINDINGS

The XPEL-TB study ran from Oct 22, 2018, to March 1, 2020. Effectiveness and cost-effectiveness outcomes were assessed from Dec 1, 2018, to Nov 30, 2019 and included 4867 women and 3139 men. On a per-test basis, the cost of decentralised ($20·46, range $17·85-25·72) and centralised ($18·20, range $16·58-24·25) Xpert testing was similar. However, decentralised testing resulted in more patients receiving appropriate Xpert testing, so the per-patient cost of decentralised testing was higher: $20·28 (range $17·68-25·48) versus $9·59 (range $7·62-14·34). The XPEL-TB strategy was estimated to cost $1332 (95% uncertainty range $763-5558) per incremental tuberculosis diagnosis and $687 ($501-1207) per incremental patient initiating tuberculosis treatment within 14 days. Cost-effectiveness was reduced in sites performing fewer than 150-250 tests annually.

INTERPRETATION

The XPEL-TB strategy facilitated higher rates of Xpert testing for tuberculosis at a similar per-test cost and modest incremental cost per tuberculosis diagnosis and treatment initiation. Decentralised Xpert testing, with appropriate implementation supports, should be scaled up to clinics with sufficient testing volume to support a single-module device.

FUNDING

The National Heart, Lung, and Blood Institute.

Comprehensive league table of cost-utility ratios: A systematic review of cost-effectiveness evidence for health policy decisions in India

Background and objectives

Although a relatively recent concept for developing countries, the developed world has been using League Tables as a policy guiding tool for a comprehensive assessment of health expenditures; country-specific "League tables" can be a very useful tool for national healthcare planning and budgeting. Presented herewith is a comprehensive league table of cost per Quality Adjusted Life Years (QALY) or Disability Adjusted Life Years (DALY) ratios derived from Health Technology Assessment (HTA) or economic evaluation studies reported from India through a systematic review.

Methods

Economic evaluations and HTAs published from January 2003 to October 2019 were searched from various databases. We only included the studies reporting common outcomes (QALY/DALY) and methodology to increase the generalizability of league table findings. To opt for a uniform criterion, a reference case approach developed by Health Technology Assessment in India (HTAIn) was used for the reporting of the incremental cost-effectiveness ratio. However, as, most of the articles expressed the outcome as DALY, both (QALY and DALY) were used as outcome indicators for this review.

Results

After the initial screening of 9,823 articles, 79 articles meeting the inclusion criteria were selected for the League table preparation. The spectrum of intervention was dominated by innovations for infectious diseases (33%), closely followed by maternal and child health (29%), and non-communicable diseases (20%). The remaining 18% of the interventions were on other groups of health issues, such as injuries, snake bites, and epilepsy. Most of the interventions (70%) reported DALY as an outcome indicator, and the rest (30%) reported QALY. Outcome and cost were discounted at the rate of 3 by 73% of the studies, at 5 by 4% of the studies, whereas 23% of the studies did not discount it. Budget impact and sensitivity analysis were reported by 18 and 73% of the studies, respectively.

Interpretation and conclusions

The present review offers a reasonably coherent league table that reflects ICER values of a range of health conditions in India. It presents an update for decision-makers for making decisions about resource allocation.

New developments in tuberculosis diagnosis and treatment

Tuberculosis (TB) is a major cause of morbidity and mortality worldwide. It is estimated that 25% of the world's population are infected with Mycobacterium tuberculosis, with a 5–10% lifetime risk of progression into TB disease. Early recognition of TB disease and prompt detection of drug resistance are essential to halting its global burden. Culture, direct microscopy, biomolecular tests and whole genome sequencing are approved methods of diagnosis; however, their widespread use is often curtailed owing to costs, local resources, time constraints and operator efficiency. Methods of optimising these diagnostics, in addition to developing novel techniques, are under review. The selection of an appropriate drug regimen is dependent on the susceptibility pattern of the isolate detected. At present, there are 16 new drugs under evaluation for TB treatment in phase I or II clinical trials, with an additional 22 drugs in preclinical stages. Alongside the development of these new drugs, most of which are oral medications, new shorter regimes are under evaluation. The aim of these shorter regimens is to encourage patient adherence, and prevent relapse or the evolution of further drug resistance. Screening for TB infection, especially in vulnerable populations, provides an opportunity for intervention prior to progression towards infectious TB disease. New regimens are currently under evaluation to assess the efficacy of shorter durations of treatment in this population. In addition, there is extensive research into the use of post-exposure vaccinations in this cohort. Worldwide collaboration and sharing of expertise are essential to our ultimate aim of global eradication of TB disease.

Early detection of drug resistance is essential to our goal of global eradication of TB. Tolerable drugs and shorter regimens promote patient adherence. Treating TB infection in vulnerable groups will prevent further global spread of TB disease.https://bit.ly/3oUW0SN

Economic Analyses of Respiratory Tract Infection Diagnostics: A Systematic Review

BACKGROUND

Diagnostic testing for respiratory tract infections is a tool to manage the current COVID-19 pandemic, as well as the rising incidence of antimicrobial resistance. At the same time, new European regulations for market entry of in vitro diagnostics, in the form of the in vitro diagnostic regulation, may lead to more clinical evidence supporting health-economic analyses.

OBJECTIVE

The objective of this systematic review was to review the methods used in economic evaluations of applied diagnostic techniques, for all patients seeking care for infectious diseases of the respiratory tract (such as pneumonia, pulmonary tuberculosis, influenza, sinusitis, pharyngitis, sore throats and general respiratory tract infections).

METHODS

Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, articles from three large databases of scientific literature were included (Scopus, Web of Science and PubMed) for the period January 2000 to May 2020.

RESULTS

A total of 70 economic analyses are included, most of which use decision tree modelling for diagnostic testing for respiratory tract infections in the community-care setting. Many studies do not incorporate a generally comparable clinical outcome in their cost-effectiveness analysis: fewer than half the studies (33/70) used generalisable outcomes such as quality-adjusted life-years. Other papers consider outcomes related to the accuracy of the test or outcomes related to the prescribed treatment. The time horizons of the studies generally are limited.

CONCLUSIONS

The methods to economically assess diagnostic tests for respiratory tract infections vary and would benefit from clear recommendations from policy makers on the assessed time horizon and outcomes used.

Diagnostic accuracy of the FluoroType MTB and MTBDR VER 2.0 assays for the centralized high-throughput detection of Mycobacterium tuberculosis complex DNA and isoniazid and rifampicin resistance

OBJECTIVES

To evaluate the accuracy of two new molecular diagnostic tests for the detection of drug-resistant tuberculosis, the FluoroType MTB and MTBDR VER 2.0 assays, in combination with manual and automated DNA extraction methods.

METHODS

Sputa from 360 Xpert Ultra Mycobacterium tuberculosis complex (MTBC)-positive patients and 250 Xpert Ultra MTBC-negative patients were tested. GenoType MTBDRplus served as reference for MTBC and drug resistance detection. Sanger sequencing was used to resolve discrepancies.

RESULTS

FluoroType MTB VER 2.0 showed similar MTBC sensitivity compared with FluoroType MTBDR VER 2.0 (manual DNA extraction: 91.6% (294/321) versus 89.8% (291/324); p 0.4); automated DNA extraction: 92.1% (305/331) versus 87.7% (291/332); p 0.05)). FluoroType MTBDR VER2.0 showed comparable diagnostic accuracy to FluoroType MTBDR VER1.0 as previously reported for the detection of MTBC and rifampicin and isoniazid resistance.

CONCLUSIONS

The FluoroType MTB and MTBDR VER 2.0 assays together with an automated DNA extraction and PCR set-up platform may improve laboratory operational efficiency for the diagnosis of MTBC and resistance to rifampicin and isoniazid and show promise for the implementation in a centralized molecular drug susceptibility testing model.

Unlocking the health system barriers to maximise the uptake and utilisation of molecular diagnostics in low-income and middle-income country setting

BACKGROUND

Early access to diagnosis is crucial for effective management of any disease including tuberculosis (TB). We investigated the barriers and opportunities to maximise uptake and utilisation of molecular diagnostics in routine healthcare settings.

METHODS

Using the implementation of WHO approved TB diagnostics, Xpert Mycobacterium tuberculosis/rifampicin (MTB/RIF) and Line Probe Assay (LPA) as a benchmark, we evaluated the barriers and how they could be unlocked to maximise uptake and utilisation of molecular diagnostics.

RESULTS

Health officers representing 190 districts/counties participated in the survey across Kenya, Tanzania and Uganda. The survey findings were corroborated by 145 healthcare facility (HCF) audits and 11 policy-maker engagement workshops. Xpert MTB/RIF coverage was 66%, falling behind microscopy and clinical diagnosis by 33% and 1%, respectively. Stratified by HCF type, Xpert MTB/RIF implementation was 56%, 96% and 95% at district, regional and national referral hospital levels. LPA coverage was 4%, 3% below culture across the three countries. Out of 111 HCFs with Xpert MTB/RIF, 37 (33%) used it to full capacity, performing ≥8 tests per day of which 51% of these were level five (zonal consultant and national referral) HCFs. Likewise, 75% of LPA was available at level five HCFs. Underutilisation of Xpert MTB/RIF and LPA was mainly attributed to inadequate-utilities, 26% and human resource, 22%. Underfinancing was the main reason underlying failure to acquire molecular diagnostics. Second to underfinancing was lack of awareness with 33% healthcare administrators and 49% practitioners were unaware of LPA as TB diagnostic. Creation of a national health tax and decentralising its management was proposed by policy-makers as a booster of domestic financing needed to increase access to diagnostics.

CONCLUSION

Our findings suggest higher uptake and utilisation of molecular diagnostics at tertiary level HCFs contrary to the WHO recommendation. Country-led solutions are crucial for unlocking barriers to increase access to diagnostics.

Geospatial evaluation of trade-offs between equity in physical access to healthcare and health systems efficiency

Introduction

Decisions regarding the geographical placement of healthcare services require consideration of trade-offs between equity and efficiency, but few empirical assessments are available. We applied a novel geospatial framework to study these trade-offs in four African countries.

Methods

Geolocation data on population density (a surrogate for efficiency), health centres and cancer referral centres in Kenya, Malawi, Tanzania and Rwanda were obtained from online databases. Travel time to the closest facility (a surrogate for equity) was estimated with 1 km resolution using the Access Mod 5 least cost distance algorithm. We studied associations between district-level average population density and travel time to closest facility for each country using Pearson’s correlation, and spatial autocorrelation using the Global Moran’s I statistic. Geographical clusters of districts with inefficient resource allocation were identified using the bivariate local indicator of spatial autocorrelation.

Results

Population density was inversely associated with travel time for all countries and levels of the health system (Pearson’s correlation range, health centres: −0.89 to −0.71; cancer referral centres: −0.92 to −0.43), favouring efficiency. For health centres, negative spatial autocorrelation (geographical clustering of dissimilar values of population density and travel time) was weaker in Rwanda (−0.310) and Tanzania (−0.292), countries with explicit policies supporting equitable access to rural healthcare, relative to Kenya (−0.579) and Malawi (−0.543). Stronger spatial autocorrelation was observed for cancer referral centres (Rwanda: −0.341; Tanzania: −0.259; Kenya: −0.595; Malawi: −0.666). Significant geographical clusters of sparsely populated districts with long travel times to care were identified across countries.

Conclusion

Negative spatial correlations suggested that the geographical distribution of health services favoured efficiency over equity, but spatial autocorrelation measures revealed more equitable geographical distribution of facilities in certain countries. These findings suggest that even when prioritising efficiency, thoughtful decisions regarding geographical allocation could increase equitable physical access to services.

Validation of Differentially Expressed Immune Biomarkers in Latent and Active Tuberculosis by Real-Time PCR

Tuberculosis (TB) remains a major global threat and diagnosis of active TB ((ATB) both extra-pulmonary (EPTB), pulmonary (PTB)) and latent TB (LTBI) infection remains challenging, particularly in high-burden countries which still rely heavily on conventional methods. Although molecular diagnostic methods are available, e.g., Cepheid GeneXpert, they are not universally available in all high TB burden countries. There is intense focus on immune biomarkers for use in TB diagnosis, which could provide alternative low-cost, rapid diagnostic solutions. In our previous gene expression studies, we identified peripheral blood leukocyte (PBL) mRNA biomarkers in a non-human primate TB aerosol-challenge model. Here, we describe a study to further validate select mRNA biomarkers from this prior study in new cohorts of patients and controls, as a prerequisite for further development. Whole blood mRNA was purified from ATB patients recruited in the UK and India, LTBI and two groups of controls from the UK (i) a low TB incidence region (CNTRLA) and (ii) individuals variably-domiciled in the UK and Asia ((CNTRLB), the latter TB high incidence regions). Seventy-two mRNA biomarker gene targets were analyzed by qPCR using the Roche Lightcycler 480 qPCR platform and data analyzed using GeneSpring™ 14.9 bioinformatics software. Differential expression of fifty-three biomarkers was confirmed between MTB infected, LTBI groups and controls, seventeen of which were significant using analysis of variance (ANOVA): CALCOCO2, CD52, GBP1, GBP2, GBP5, HLA-B, IFIT3, IFITM3, IRF1, LOC400759 (GBP1P1), NCF1C, PF4V1, SAMD9L, S100A11, TAF10, TAPBP, and TRIM25. These were analyzed using receiver operating characteristic (ROC) curve analysis. Single biomarkers and biomarker combinations were further assessed using simple arithmetic algorithms. Minimal combination biomarker panels were delineated for primary diagnosis of ATB (both PTB and EPTB), LTBI and identifying LTBI individuals at high risk of progression which showed good performance characteristics. These were assessed for suitability for progression against the standards for new TB diagnostic tests delineated in the published World Health Organization (WHO) technology product profiles (TPPs).

Determining the value of TB active case-finding: current evidence and methodological considerations

Active case-finding (ACF) is an important component of the End TB Strategy. However, ACF is resource-intensive, and the economics of ACF are not well-understood. Data on the costs of ACF are limited, with little consistency in the units and methods used to estimate and report costs. Mathematical models to forecast the long-term effects of ACF require empirical measurements of the yield, timing and costs of case detection. Pragmatic trials offer an opportunity to assess the cost-effectiveness of ACF interventions within a 'real-world´ context. However, such analyses generally require early introduction of economic evaluations to enable prospective data collection on resource requirements. Closing the global case-detection gap will require substantial additional resources, including continued investment in innovative technologies. Research is essential to the optimal implementation, cost-effectiveness, and affordability of ACF in high-burden settings. To assess the value of ACF, we must prioritize the collection of high-quality data regarding costs and effectiveness, and link those data to analytical models that are adapted to local settings.

Trade-offs between cost and accuracy in active case finding for tuberculosis: A dynamic modelling analysis

BACKGROUND

Active case finding (ACF) may be valuable in tuberculosis (TB) control, but questions remain about its optimum implementation in different settings. For example, smear microscopy misses up to half of TB cases, yet is cheap and detects the most infectious TB cases. What, then, is the incremental value of using more sensitive and specific, yet more costly, tests such as Xpert MTB/RIF in ACF in a high-burden setting?

METHODS AND FINDINGS

We constructed a dynamic transmission model of TB, calibrated to be consistent with an urban slum population in India. We applied this model to compare the potential cost and impact of 2 hypothetical approaches following initial symptom screening: (i) 'moderate accuracy' testing employing a microscopy-like test (i.e., lower cost but also lower accuracy) for bacteriological confirmation and (ii) 'high accuracy' testing employing an Xpert-like test (higher cost but also higher accuracy, while also detecting rifampicin resistance). Results suggest that ACF using a moderate-accuracy test could in fact cost more overall than using a high-accuracy test. Under an illustrative budget of US$20 million in a slum population of 2 million, high-accuracy testing would avert 1.14 (95% credible interval 0.75-1.99, with p = 0.28) cases relative to each case averted by moderate-accuracy testing. Test specificity is a key driver: High-accuracy testing would be significantly more impactful at the 5% significance level, as long as the high-accuracy test has specificity at least 3 percentage points greater than the moderate-accuracy test. Additional factors promoting the impact of high-accuracy testing are that (i) its ability to detect rifampicin resistance can lead to long-term cost savings in second-line treatment and (ii) its higher sensitivity contributes to the overall cases averted by ACF. Amongst the limitations of this study, our cost model has a narrow focus on the commodity costs of testing and treatment; our estimates should not be taken as indicative of the overall cost of ACF. There remains uncertainty about the true specificity of tests such as smear and Xpert-like tests in ACF, relating to the accuracy of the reference standard under such conditions.

CONCLUSIONS

Our results suggest that cheaper diagnostics do not necessarily translate to less costly ACF, as any savings from the test cost can be strongly outweighed by factors including false-positive TB treatment, reduced sensitivity, and foregone savings in second-line treatment. In resource-limited settings, it is therefore important to take all of these factors into account when designing cost-effective strategies for ACF.

ERS International Congress, Madrid, 2019: highlights from the Respiratory Infections Assembly

The European Respiratory Society (ERS) International Congress organised in Madrid, Spain, in 2019 welcomed >22 000 participants from 134 countries. For each ERS assembly, an impressive number of abstracts were submitted. The topics covered by Assembly 10 (Respiratory Infections and Tuberculosis) were included this year in the top five research areas with the most submitted abstracts, with a total of 424 abstracts accepted for presentation. As it would be difficult for any delegate to stay up to date with all the scientific advances in the field, we wanted to highlight three of the Congress sessions that included presentations on respiratory infections and tuberculosis that we deemed as important and we hope the readers will consider this material of great interest.

The cost-effectiveness of a bedaquiline-containing short-course regimen for the treatment of multidrug-resistant tuberculosis in South Africa

Background: Bedaquiline-containing regimens have demonstrated improved outcomes over injectable-containing regimens in the long-term treatment of multidrug-resistant tuberculosis (MDR-TB). Recently, the World Health Organization (WHO) recommended replacing injectables in the standard short-course regimen (SCR) with a bedaquiline-containing regimen. The South African national TB program similarly recommends a bedaquiline-containing regimen. Here, we investigated the cost-effectiveness of a bedaquiline-containing SCR versus an injectable-containing SCR for the treatment of MDR-TB in South Africa.Methods: A Markov model was adapted to simulate the incidence of active patients with MDR-TB. Patients could transition through eight health states: active MDR-TB, culture conversion, cure, follow-up loss, secondary MDR-TB, extensively DR-TB, end-of-life care, and death. A 5% discount was assumed on costs and outcomes. Health outcomes were expressed as disability-adjusted life years (DALYs).Results: Over a 10-year time horizon, a bedaquiline-containing SCR dominated an injectable-containing SCR, with an incremental saving of US $982 per DALY averted. A bedaquiline-containing SCR was associated with lower total costs versus an injectable-containing SCR (US $597 versus $657 million), of which US $3.2 versus $21.9 million was attributed to adverse event management.Conclusions: Replacing an injectable-containing SCR with a bedaquiline-containing SCR is cost-effective, offering a cost-saving alternative with improved patient outcomes for MDR-TB.

National TB program shortages as potential factor for poor-quality TB care cascade: Healthcare workers' perspective from Beira, Mozambique

Background

Mozambique is one of the countries with the deadly implementation gaps in the tuberculosis (TB) care and services delivery. In-hospital delays in TB diagnosis and treatment, transmission and mortality still persist, in part, due to poor-quality of TB care cascade.

Objective

We aimed to assess, from the healthcare workers’ (HCW) perspective, factors associated with poor-quality TB care cascade and explore local sustainable suggestions to improve in-hospital TB management.

Methods

In-depth interviews and focus group discussions were conducted with different categories of HCW. Audio-recording and written notes were taken, and content analysis was performed through atlas.ti7.

Results

Bottlenecks within hospital TB care cascade, lack of TB staff and task shifting, centralized and limited time of TB laboratory services, and fear of healthcare workers getting infected by TB were mentioned to be the main factors associated with implementation gaps. Interviewees believe that task shifting from nurses to hospital auxiliary workers, and from higher and well-trained to lower HCW are accepted and feasible. The expansion and use of molecular TB diagnostic tools are seen by the interviewees as a proper way to fight effectively against both sensitive and MDR TB. Ensuring provision of N95 respiratory masks is believed to be an essential requirement for effective engagement of the HCW on high-quality in-hospital TB care. For monitoring and evaluation, TB quality improvement teams in each health facility are considered to be an added value.

Conclusion

Shortage of resources within the national TB control programme is one of the potential factors for poor-quality of the TB care cascade. Task shifting of TB care and services delivery, decentralization of the molecular TB diagnostic tools, and regular provision of N95 respiratory masks should contribute not just to reduce the impact of resource scarceness, but also to ensure proper TB diagnosis and treatment to both sensitive and MDR TB.

Chest Radiography and Xpert MTB/RIF® Testing in Persons with Presumptive Pulmonary TB: Gaps and Challenges from a District in Karnataka, India

Background

In India, as per the latest diagnostic algorithm, all persons with presumptive pulmonary TB (PPTB) are required to undergo sputum smear examination and chest radiography (CXR) upfront. Those with sputum smear positive, sputum smear negative, but CXR lesions suggestive of TB or those with strong clinical suspicion of TB are expected to undergo Xpert MTB/RIF® assay test (also known as CB-NAAT (cartridge-based nucleic acid amplification test)).

Objective

To assess what proportion of PPTB who are undergoing sputum smear examination at microscopy centers of public health facilities have undergone CXR and CB-NAAT. To explore the barriers for uptake of CXR and CB-NAAT from the public health care provider's perspective.

Methods

We conducted a sequential explanatory mixed-methods study in Chikkaballapur district of Karnataka State, South India. The quantitative component involved a review of records of PPTB who had undergone sputum smear examination in a representative sample of seven microscopy centers. The qualitative component involved key informant interviews with four medical officers and group interviews with 9 paramedical staff.

Results

In February and March 2019, about 732 PPTB had undergone smear examination. Of these, 301 (41%) had undergone CXR and 49 (7%) had undergone CB-NAAT. The proportion of PPTB who had undergone CXR varied across the seven microscopy centers (0% to 89%). CB-NAAT was higher in PPTB from urban areas when compared to rural areas (8% vs. 3%) and in those who were smear positive when compared to smear negative (65% vs. 2%). The major barriers for CXR and CB-NAAT were nonavailability of these tests at all microscopy centers and patients' reluctance to travel to the facilities where CXR and CB-NAAT services are available.

Conclusions

CXR and CB-NAAT of PPTB are suboptimal. RNTCP should undertake measures to address these gaps in implementing its latest diagnostic algorithm.