Investigating the impact of TB case-detection strategies and the consequences of false positive diagnosis through mathematical modelling

The effectiveness of community-wide screening for pulmonary tuberculosis: a systematic review

This systematic review evaluated the effectiveness of community-wide screening for pulmonary tuberculosis (TB) in high-burden areas by analysing randomised controlled trials (RCTs). The review focused on interventions offering TB screening to entire communities, comparing them to standard care or alternative approaches. The main outcome assessed was microbiologically confirmed TB diagnoses, including rates and prevalence. We searched MEDLINE, Embase, Cochrane Central Register of Controlled Trials, WHO Global Index Medicus, Web of Science, and trial registries up to 27 May 2024, without language restrictions. Screening, data extraction, and risk of bias assessment were done in duplicate. Results were not pooled. Certainty of the evidence was assessed using GRADE. PROSPERO: CRD42023453356. We included six cluster-RCTs after screening 2460 titles/abstracts and 86 full-text articles. The evidence for symptom screening was very uncertain. We found that sputum smear microscopy screening may result in little to no difference in the prevalence of culture-confirmed TB (n = 962,655, RR 1.09; 95% CI: 0.86-1.38, 1 RCT, low certainty evidence). Community-wide nucleic acid amplification test (NAAT) screening probably reduces the prevalence of NAAT-positive TB (n = 105,108, RR 0.56; 95% CI: 0.40-0.78, 1 RCT, moderate certainty evidence). Community-wide screening for pulmonary TB may reduce TB prevalence if done annually with an accurate screening test and high coverage.

Drug resistant tuberculosis: Implications for transmission, diagnosis, and disease management

Drug resistant tuberculosis contributes significantly to the global burden of antimicrobial resistance, often consuming a large proportion of the healthcare budget and associated resources in many endemic countries. The rapid emergence of resistance to newer tuberculosis therapies signals the need to ensure appropriate antibiotic stewardship, together with a concerted drive to develop new regimens that are active against currently circulating drug resistant strains. Herein, we highlight that the current burden of drug resistant tuberculosis is driven by a combination of ongoing transmission and the intra-patient evolution of resistance through several mechanisms. Global control of tuberculosis will require interventions that effectively address these and related aspects. Interrupting tuberculosis transmission is dependent on the availability of novel rapid diagnostics which provide accurate results, as near-patient as is possible, together with appropriate linkage to care. Contact tracing, longitudinal follow-up for symptoms and active mapping of social contacts are essential elements to curb further community-wide spread of drug resistant strains. Appropriate prophylaxis for contacts of drug resistant index cases is imperative to limit disease progression and subsequent transmission. Preventing the evolution of drug resistant strains will require the development of shorter regimens that rapidly eliminate all populations of mycobacteria, whilst concurrently limiting bacterial metabolic processes that drive drug tolerance, mutagenesis and the ultimate emergence of resistance. Drug discovery programs that specifically target bacterial genetic determinants associated with these processes will be paramount to tuberculosis eradication. In addition, the development of appropriate clinical endpoints that quantify drug tolerant organisms in sputum, such as differentially culturable/detectable tubercle bacteria is necessary to accurately assess the potential of new therapies to effectively shorten treatment duration. When combined, this holistic approach to addressing the critical problems associated with drug resistance will support delivery of quality care to patients suffering from tuberculosis and bolster efforts to eradicate this disease.

The effect of empirical and laboratory-confirmed tuberculosis on treatment outcomes

The World Health Organization (WHO) criteria for diagnosing and treating Tuberculosis (TB) includes clinical signs, therefore not requiring bacteriological laboratory confirmation. In resource-limited settings, including Kenya, this empirical TB treatment is routine practice however limited data exist on patient clinical outcomes when comparing the method of diagnosis. We evaluated TB treatment outcomes comparing clinically diagnosed and bacteriologically confirmed TB, 6 months after starting treatment of TB in a rural county in Kenya. Our analysis compared patients with a clinical versus a bacteriologically confirmed TB diagnosis. In this retrospective analysis, we included all adults (≥ 18 years) starting treatment of TB and followed up for 6 months, within the County TB surveillance database from 2012 to 2018. Patients included from both public and private facilities. The TB treatment outcomes assessed included treatment success, treatment failure, death, defaulted and transferred out. We used survival regression models to assess effect of type of diagnosis on TB treatment outcome defining time at risk from date of starting treatment to experiencing one of the treatment outcomes or completing 6-months of treatment. A total of 12,856 patients; median age 37 [IQR 28 − 50] years were included. 7639 (59%) were male while 11,339 (88%) were pulmonary TB cases. Overall, 11,633 (90%) were given first-line TB treatment and 3791 (29%) were HIV infected. 6472 (50%) of the patients were clinically diagnosed of whom 4521/6472 (70%) had a negative sputum/GeneXpert test. During the study 5565 person-years (PYs) observed, treatment success was 82% and 83% amongst clinically and bacteriologically diagnosed patients (P = 0.05). There were no significant differences in defaulting (P = 0.70) or transfer out (P = 0.19) between clinically and bacteriologically diagnosed patients. Mortality was significantly higher among clinically diagnosed patients: 639 (9.9%) deaths compared to 285 (4.5%) amongst the bacteriologically diagnosed patients; aHR 5.16 (95%CI 2.17 − 12.3) P < 0.001. Our study suggests survival during empirical TB treatment is significantly lower compared to patients with laboratory evidence, irrespective of HIV status and age. To improve TB treatment outcomes amongst clinically diagnosed patients, we recommend systematic screening for comorbidities, prompt diagnosis and management of other infections.

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.

Factors associated with recovery and the abandonment of tuberculosis treatment in the incarcerated population

OBJECTIVE

This study aimed to investigate the factors associated with the outcomes of recovery and abandonment in the incarcerated population with tuberculosis.

METHODS

A quantitative and observational analytical study was performed with data from the Notification Disease Information System (Sinan), tuberculosis data from the incarcerated population in the state of Paraiba from 2007 to 2016; Notifications of individuals over the age of 18, reported as "new cases" and the outcome, "recovery" or "abandonment" status were included. Those people who until December 2016 had no outcome information were excluded. Analyses were performed using bivariate and multivariate statistics from the Poisson regression.

RESULTS

Of the 614 notifications, most were male (93.8%). In the bivariate analysis, there was a statistically relevant association of outcomes with Acquired Immunodeficiency Syndrome (p = 0.044), Human Immunodeficiency Virus (HIV) serology (p = 0.048) and lack of completion of follow-up bacilloscopy (p = 0.001). In the adjusted multivariate analysis, Acquired Immunodeficiency Syndrome (RR = 1.998; 95%CI 1.078 - 3.704; p = 0.028) and lack of completion of follow-up bacilloscopy (RR = 5.251; 95%CI 2.158 - 12.583; p <0.001*) remained significantly associated with the dropout outcome.

CONCLUSION

Recovery and abandonment outcomes were mainly associated with whether the follow-up bacilloscopy was performed or not and Acquired Immunodeficiency Syndrome.

Community health care workers in pursuit of TB: Discourses and dilemmas

Community-led tuberculosis (TB) active case finding is widely promoted, heavily funded, but many efforts fail to meet expectations. The underlying reasons why TB symptom screening programs underperform are poorly understood. This study examines Nigerian stakeholders' insights to characterize the mechanisms, enabling structures and influences that lead programs to succeed or fail. Eight focus group discussions were held with Community Health Workers (CWs) from four models of community-based TB screening and referral. In-depth interviews were conducted with 2 State TB program managers, 8 Community based organizations (CBOs), and 6 state TB and Leprosy Local Government supervisors. Transcripts were coded using Framework Analysis to assess how divergent understandings of CWs' roles, expectations, as well as design, political and structural factors contributed to the observed underperformance. Altruism, religious faith, passion, and commitment to the health and well-being of their communities were reasons CWs gave for starting TB symptom screening and referral. Yet politicized or donor-driven CWs' selection processes at times yielded implementers without a firm grounding in TB or the social, cultural, and physical terrain. CWs encountered suspicion, stigma, and hostility in both health facilities and communities. As the interface between the TB program and communities, CWs often bore the brunt of frustrations with inadequate TB services and CBO/iNGO collaboration. Some CWs expended their own social and financial capital to cover gaps in the active case finding (ACF) programs and public health services or curtailed their screening activities. Effective community-led TB active case finding is challenging to design, implement and sustain. Contrary to conventional wisdom, CWs did not experience it as inherently empowering. Sustainable, supportive models that combine meaningful engagement for communities with effective program stewardship and governance are needed. Crucially effective and successful implementation of community-based TB screening and referral requires a functional public health system to which to refer.