Sensitivity of Various Case Detection Algorithms for Community-based Tuberculosis Screening.

Using data from 388 people diagnosed with tuberculosis through a community-based screening program in Lima, Peru, we estimated that cough screening followed by sputum smear microscopy would have detected only 23% of cases found using an algorithm of radiographic screening followed by rapid nucleic acid amplification testing and clinical evaluation.

Geospatial analysis of reported activity locations to identify sites for tuberculosis screening.

Mobile screening units can help close tuberculosis case detection gaps. Placing screening units where people at high risk for undiagnosed tuberculosis preferentially spend time could make screening more resource-effective. We conducted a case-control study in Lima, Peru to identify locations where people with tuberculosis were more likely to spend time than community controls. We surveyed participants about activity locations over the past 6 months. We used density-based clustering to assess how patient and control activity locations differed, and logistic regression to compare location-based exposures. We included 109 tuberculosis patients and 79 controls. In density-based clustering analysis, the two groups had similar patterns of living locations, but their work locations clustered in distinct areas. Both groups were similarly likely to use public transit, but patients predominantly used buses and were less likely to use rapid transit (adjusted odds ratio [aOR] 0.31, 95% confidence interval [CI] 0.10-0.96) or taxis (aOR 0.42, 95% CI 0.21-0.85). Patients were more likely to have spent time in prison (aOR 11.55, 95% CI 1.48-90.13). Placing mobile screening units at bus terminals serving locations where tuberculosis patients have worked and within and around prisons could help reach people with undiagnosed tuberculosis.

Geographic accessibility to health facilities predicts uptake of community-based tuberculosis screening in an urban setting.

OBJECTIVES: Annually, more than 30% of individuals with tuberculosis (TB) remain undiagnosed. We aimed to assess whether geographic accessibility measures can identify neighborhoods that would benefit from TB screening services targeted toward closing the diagnosis gap. METHODS: We used data from a community-based mobile TB screening program in Carabayllo district, Lima, Peru. We constructed four accessibility measures from the geographic center of neighborhoods to health facilities. We used logistic regression to assess the association between these measures and screening uptake in one's residential neighborhood versus elsewhere, with quasi-information criterion values to assess the association. RESULTS: We analyzed the screening locations for 25,000 Carabayllo residents from 49 neighborhoods. Pedestrian walk time was preferable to Euclidean distance or vehicular time in our models. For each additional 12 minutes walking time between the neighborhood and the health facility, the odds of residents using TB screening units located in their neighborhoods increased by 50% (95% CI: 26%-78%). Females had 9% (95% CI: 3%-16%) increased odds versus males of using a screening unit in their own neighborhood. CONCLUSION: Placing mobile TB screening units in neighborhoods with longer pedestrian time to access health facilities could benefit individuals who face more acute access barriers to health care.

Age-specific effectiveness of a tuberculosis screening intervention in children.

OBJECTIVE: To apply a cascade-of-care framework to evaluate the effectiveness-by age of the child-of an intensified tuberculosis patient-finding intervention. DESIGN: From a prospective screening program at four hospitals in Pakistan (2014-2016) we constructed a care cascade comprising six steps: screened, positive screen, evaluated, diagnosed, started treatment, and successful outcome. We evaluated the cascade by each year of age from 0 to 14 and report the age-specific mean proportion and standard deviation. RESULTS: On average across all ages, only 12.5% (standard deviation: 2.0%) of children with a positive screen were not evaluated. Among children who had a complete evaluation, the highest percentages of children diagnosed with tuberculosis were observed in children 0-4 (mean: 31.9%; standard deviation: 4.8%), followed by lower percentages in children 5-9 (mean: 22.4%; standard deviation: 2.2%), and 10-14 (mean: 26.0%; standard deviation:5.4%). Nearly all children diagnosed with tuberculosis initiated treatment, and an average of 93.3% (standard deviation: 3.3%) across all ages had successful treatment outcomes. CONCLUSIONS: This intervention was highly effective across ages 0-14 years. Our study illustrates the utility of applying operational analyses of age-stratified cascades to identify age-specific gaps in pediatric tuberculosis care that can guide future, novel interventions to close these gaps.

A role for community-level socioeconomic indicators in targeting tuberculosis screening interventions.

Tuberculosis screening programs commonly target areas with high case notification rates. However, this may exacerbate disparities by excluding areas that already face barriers to accessing diagnostic services. We compared historic case notification rates, demographic, and socioeconomic indicators as predictors of neighborhood-level tuberculosis screening yield during a mobile screening program in 74 neighborhoods in Lima, Peru. We used logistic regression and Classification and Regression Tree (CART) analysis to identify predictors of screening yield. During February 7, 2019-February 6, 2020, the program screened 29,619 people and diagnosed 147 tuberculosis cases. Historic case notification rate was not associated with screening yield in any analysis. In regression analysis, screening yield decreased as the percent of vehicle ownership increased (odds ratio [OR]: 0.76 per 10% increase in vehicle ownership; 95% confidence interval [CI]: 0.58-0.99). CART analysis identified the percent of blender ownership (≤ 83.1% vs > 83.1%; OR: 1.7; 95% CI: 1.2-2.6) and the percent of TB patients with a prior tuberculosis episode (> 10.6% vs ≤ 10.6%; OR: 3.6; 95% CI: 1.0-12.7) as optimal predictors of screening yield. Overall, socioeconomic indicators were better predictors of tuberculosis screening yield than historic case notification rates. Considering community-level socioeconomic characteristics could help identify high-yield locations for screening interventions.

Closing delivery gaps in the treatment of tuberculosis infection: Lessons from implementation research in Peru.

BACKGROUND: Targeted testing and treatment of TB infection to prevent disease is a pillar of TB elimination. Despite recent global commitments to greatly expand access to preventive treatment for TB infection, there remains a lack of research on how best to expand preventive treatment programs in settings with high TB burdens. METHODS: We conducted implementation research in Lima, Peru, around a multifaceted intervention to deliver TB preventive treatment to close contacts of all ages, health care workers, and people in congregate settings. Key interventions included use of the interferon gamma release assay (IGRA), specialist support for generalist physicians at primary-level health facilities, and treatment support by community health workers. We applied a convergent mixed methods approach to evaluate feasibility and acceptability based on a care cascade framework. FINDINGS: During April 2019-January 2020, we enrolled 1,002 household contacts, 148 non-household contacts, 107 residents and staff of congregate settings, and 357 health care workers. Cumulative completion of the TB preventive care cascade was 34% for contacts <5 years old, 28% for contacts 5-19 years old, 18% for contacts ≥20 years old, 0% for people in congregate settings, and 4% of health care workers. IGRA testing was acceptable to adults exposed to TB. Preventive treatment was acceptable to contacts, but less acceptable to physicians, who frequently had doubts about prescribing preventive treatment for adults. Community-based treatment support was both acceptable and feasible, and periodic home-visits or calls were identified as facilitators of adherence. CONCLUSIONS: We attempted to close the gap in TB preventive treatment in Peru by expanding preventive services to adult contacts and other risk groups. While suboptimal, care cascade completion for adult contacts was consistent with what has been observed in high-income settings. The major losses in the care cascade occurred in completing evaluations and having doctors prescribe preventive treatment.