Search

Rifampin-resistant tuberculosis (RR-TB) is a key contributor to global antimicrobial resistance; >400,000 persons had RR-TB in 2020, nearly 40% of whom probably died as a result (1). More than 57% [...]

IntroductionIn high-burden settings, low-complexity screening tests for tuberculosis (TB) could expand the reach of community-based case-finding efforts. The potential costs and cost-effectiveness of approaches incorporating these tests are poorly understood.MethodsWe developed a microsimulation model assessing 3 approaches to community-based case-finding in hypothetical populations (India-, South Africa-, The Philippines-, Uganda-, and Vietnam-like settings) with TB prevalence 4 times that of national estimates: (1) screening with a point-of-care C-reactive protein (CRP) test, (2) screening with a more sensitive "Hypothetical Screening test" (95% sensitive for Xpert Ultra-positive TB, 70% specificity; equipment/labor costs similar to Xpert Ultra, but using a $2 cartridge) followed by sputum Xpert Ultra if positive, or (3) testing all individuals with sputum Xpert Ultra. Costs are expressed in 2023 US dollars and include treatment costs.ResultsUniversal Xpert Ultra was estimated to cost a mean $4.0 million (95% uncertainty range: $3.5 to $4.6 million) and avert 3200 (2600 to 3900) TB-related disability-adjusted life years (DALYs) per 100 000 people screened ($670 [The Philippines] to $2000 [Vietnam] per DALY averted). CRP was projected to cost $550 (The Philippines) to $1500 (Vietnam) per DALY averted but with 44% fewer DALYs averted. The Hypothetical Screening test showed minimal benefit compared to universal Xpert Ultra, but if specificity were improved to 95% and per-test cost to $4.5 (all-inclusive), this strategy could cost $390 (The Philippines) to $940 (Vietnam) per DALY averted.ConclusionsScreening tests can meaningfully improve the cost-effectiveness of community-based case-finding for TB but only if they are sensitive, specific, and inexpensive.

Rationale: C-reactive protein (CRP) has demonstrated utility as a point-of-care triage test for tuberculosis (TB) in clinical settings, particularly among people with human immunodeficiency virus (HIV), but its performance for general-population TB screening is not well characterized. Objective: To assess the accuracy of CRP for detecting pulmonary TB disease among individuals undergoing community-based screening or presenting for evaluation of TB symptoms in Kampala, Uganda. Methods: We pooled data from two case–control studies conducted between May 2018 and December 2022 among adolescents and adults (⩾15 yr) in Kampala, Uganda. We conducted community-based screening for TB, regardless of symptoms. We enrolled people with Xpert MTB/RIF Ultra–positive (including trace) sputum results and a sample of people with Ultra-negative results. We also enrolled symptomatic patients diagnosed with TB and controls with negative TB evaluations from ambulatory care settings. Participants underwent further evaluation, including sputum culture, CRP, and HIV testing. We assessed the accuracy of CRP alone or with symptom screening against a bacteriologic reference standard. Our primary analysis evaluated the sensitivity and specificity of CRP at a cutoff of 5 mg/L. Diagnostic performance was summarized by calculating the area under the receiver operating curve (AUC). Results: In the community setting (n = 544), CRP ⩾ 5 mg/L had a sensitivity of 55.3% (95% confidence interval, 47.0–63.4%) and specificity of 84.7% (79.7–88.8%) for confirmed TB; AUC was 0.75 (0.70–0.79). Screening for CRP ⩾ 5 mg/L or positive symptoms increased sensitivity to 92.0% (86.4–95.8%) at the expense of specificity (57.1% [50.8–63.2%]). In the ambulatory care setting (n = 944), sensitivity of CRP ⩾ 5 mg/L was 86.7% (81.8–90.7%), specificity was 68.6% (64.8–72.2%), and AUC (0.84 [0.81–0.87]) did not differ significantly by HIV status. CRP ⩾ 5 mg/L was >90% sensitive among individuals with a medium or high semiquantitative Xpert result in both settings. Conclusions: Although CRP did not meet World Health Organization (WHO) TB screening benchmarks in the community, it demonstrated high specificity, and sensitivity was high among individuals with high sputum bacillary burden who are likely to be most infectious. In ambulatory care, estimated sensitivity and specificity were each within 4 percentage points of WHO benchmarks, with no meaningful difference in performance by HIV status. [ABSTRACT FROM AUTHOR]

Background "Trace" results on Xpert MTB/RIF Ultra ("Ultra"; Cepheid) —a molecular diagnostic test for tuberculosis (TB)—are often interpreted as an indication for TB treatment, but may also represent detection of nonviable bacilli or analytical error. In community-screening settings where individual TB risk is low, there is limited guidance on how to interpret Ultra-trace results. Methods We conducted systematic Ultra TB screening of adults and adolescents (≥15 years) in Kampala, Uganda, through door-to-door and event-based sputum collection. We enrolled individuals with trace-positive sputum for detailed clinical, radiographic, and microbiological (including 2 sputum cultures, repeat Ultra, and for people with HIV, urine lipoarabinomannan) evaluation, and compared those findings with similar evaluations in controls with Ultra-negative and Ultra-positive (non-trace) sputum. Results Of 21 957 people screened with Ultra, 211 (1.0%) tested positive, including 96 (46% of positives) with trace results. Of 92 people enrolled with trace-positive sputum; 12% (11/92) were HIV-positive and 14% (13/92) had prior TB. The prevalence of TB among participants with trace-positive sputum results was 14% (13/92) by culture, 24% (22/92) using broader microbiological criteria, and 26% (24/92) after accounting for clinical diagnosis. The prevalence of cough and of abnormal chest computed tomography (CT) findings were 32% and 26%, respectively, if Ultra-negative; 34% and 54% if trace-positive/non–microbiologically confirmed; 72% and 95% if trace-positive/microbiologically confirmed; and 71% and 93% if Ultra-positive (more than trace). Conclusions Most individuals with trace-positive sputum in Ugandan communities did not have microbiologically confirmed TB but had more symptoms and chest CT abnormalities than people with Ultra-negative sputum. [ABSTRACT FROM AUTHOR]

Background Several clinical trials of tuberculosis preventive treatment (TPT) for household contacts of patients with multidrug- or rifampin-resistant tuberculosis (MDR/RR-TB) are nearing completion. The potential benefits of delivering TPT to MDR/RR-TB contacts extend beyond the outcomes that clinical trials can measure. Methods We developed an agent-based, household-structured TB and MDR/RR-TB transmission model, calibrated to an illustrative setting in India. We simulated contact investigation in households of patients with MDR/RR-TB, comparing an MDR/RR-TPT regimen (assuming 6-month duration, 70% efficacy) and associated active case finding against alternatives of contact investigation without TPT or no household intervention. We simulated the TB and MDR/RR-TB incidence averted relative to placebo over 2 years, as measurable by a typical trial, as well as the incidence averted over a longer time horizon, in the broader population, and relative to no contact investigation. Results Observing TPT and placebo recipients for 2 years as in a typical trial, MDR/RR-TPT was measured to prevent 72% (interquartile range, 45%–100%) of incident MDR/RR-TB among recipients; the median number needed to treat (NNT) to prevent 1 MDR/RR-TB case was 73, compared to placebo. This NNT decreased to 54 with 13–18 years of observation, to 27 when downstream transmission effects were also considered, and to 12 when the effects of active TB screening were included by comparing to a no-household-contact-intervention scenario. Conclusions If forthcoming trial results demonstrate efficacy, the long-term population impact of TPT for MDR/RR-TB—including the large effect of increased active TB detection among MDR/RR-TB contacts—could be much greater than suggested by trial outcomes alone. [ABSTRACT FROM AUTHOR]

This correction notice is for an article published in the journal Trials. The correction states that there was an error in the original article regarding the location of sputum collection, which was done at the TU instead of at home due to logistical constraints. The sample size section and statistical methods section were also modified to reflect changes in the non-inferiority interval and the non-inferiority margin for the primary outcome. Additionally, the author contribution section was updated to include a statement about the involvement of certain authors in the discussion related to the manuscript correction. [Extracted from the article]

Simpler, shorter, safer and more effective treatments for tuberculosis that are easily accessible to all people with tuberculosis are desperately needed. In 2016, the World Health Organization (WHO) developed target regimen profiles for the treatment of tuberculosis to make drug developers aware of both the important features of treatment regimens, and patient and programmatic needs at the country level. In view of recent ground-breaking advances in tuberculosis treatment, WHO has revised and updated these regimen profiles. We used a similar process as for the 2016 profiles, including a baseline treatment landscape analysis, an initial stakeholder survey, modelling studies estimating the impact and cost-effectiveness of novel tuberculosis treatment regimens, and an extensive stakeholder consultation. We developed target regimen profiles for the treatment of rifampicin-susceptible and rifampicin-resistant tuberculosis, as well as a pantuberculosis regimen that would be appropriate for patients with any type of tuberculosis. We describe the revised target regimen profile characteristics, with specific minimal and optimal targets to be met, rationale and justification, and aspects relevant to all target regimen profiles (drug susceptibility testing, adherence and forgiveness, treatment strategies, post-tuberculosis lung disease, and cost and access considerations). We discuss the trade-offs of proposed characteristics for decision-making at developmental or operational levels. We expect that, following these target regimen profile revisions, tuberculosis treatment developers will produce regimens that are quality-assured, affordable and widely available, and that meet the needs of affected populations. [ABSTRACT FROM AUTHOR]

Background: With numerous trials investigating novel drug combinations to treat tuberculosis, we aimed to evaluate the extent to which future improvements in tuberculosis treatment regimens could offset potential increases in drug costs., Methods: In this modelling analysis, we used an ingredients-based approach to estimate prices at which novel regimens for rifampin-susceptible and rifampin-resistant tuberculosis treatment would be cost-neutral or cost-effective compared with standards of care in India, the Philippines, and South Africa. We modelled regimens meeting targets set in the WHO's 2023 Target Regimen Profiles (TRPs). Our decision-analytical model tracked cohorts of adults initiating rifampin-susceptible or rifampin-resistant tuberculosis treatment, simulating their health outcomes and costs accumulated during and following treatment under standard-of-care and novel regimen scenarios. Price thresholds included short-term cost-neutrality (considering only savings accrued during treatment), medium-term cost-neutrality (additionally considering savings from averted retreatments and secondary cases), and cost-effectiveness (incorporating willingness-to-pay for improved health outcomes)., Findings: Total medium-term costs per person treated using standard-of-care regimens were estimated at US$450 (95% uncertainty interval 310-630) in India, $560 (350-860) in the Philippines, and $730 (530-1090) in South Africa for rifampin-susceptible tuberculosis (current drug costs $46) and $2100 (1590-2810) in India, $2610 (2090-3280) in the Philippines, and $3790 (3090-4630) in South Africa for rifampin-resistant tuberculosis (current drug costs $432). A rifampin-susceptible tuberculosis regimen meeting the optimal targets defined in the TRPs could be cost-neutral in the short term at drug costs of $140 (90-210) per full course in India, $230 (130-380) in the Philippines, and $280 (180-460) in South Africa. For rifampin-resistant tuberculosis, short-term cost-neutral thresholds were higher with $930 (720-1230) in India, $1180 (980-1430) in the Philippines, and $1480 (1230-1780) in South Africa. Medium-term cost-neutral prices were approximately $50-100 higher than short-term cost-neutral prices for rifampin-susceptible tuberculosis and $250-550 higher for rifampin-resistant tuberculosis. Health system cost-neutral prices that excluded patient-borne costs were 45-70% lower (rifampin-susceptible regimens) and 15-50% lower (rifampin-resistant regimens) than the cost-neutral prices that included patient costs. Cost-effective prices were substantially higher. Shorter duration was the most important driver of medium-term savings with novel regimens, followed by ease of adherence., Interpretation: Improved tuberculosis regimens, particularly shorter regimens or those that facilitate better adherence, could reduce overall costs, potentially offsetting higher prices., Funding: WHO., Competing Interests: Declaration of interests TSR, CL, DWD, and EAK report funding from WHO. TSR and EAK report funding from the Bill & Melinda Gates Foundation. All other authors declare no competing interests., (Copyright © 2024 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY 4.0 license.)