Tuberculosis screening costs and cost-effectiveness in high-risk groups: a systematic review.

BACKGROUND: Systematic screening for active tuberculosis (TB) is a strategy which requires the health system to seek out individuals, rather than waiting for individuals to self-present with symptoms (i.e., passive case finding). Our review aimed to summarize the current economic evidence and understand the costs and cost-effectiveness of systematic screening approaches among high-risk groups and settings. METHODS: We conducted a systematic review on economic evaluations of screening for TB disease targeting persons with clinical and/or structural risk factors, such as persons living with HIV (PLHIV) or persons experiencing homelessness. We searched three databases for studies published between January 1, 2010 and February 1, 2020. Studies were included if they reported cost and a key outcome measure. Owing to considerable heterogeneity in settings and type of screening strategy, we synthesized data descriptively. RESULTS: A total of 27 articles were included in our review; 19/27 (70%) took place in high TB burden countries. Seventeen studies took place among persons with clinical risk factors, including 14 among PLHIV, while 13 studies were among persons with structural risk factors. Nine studies reported incremental cost-effectiveness ratios (ICERs) ranging from US$51 to $1980 per disability-adjusted life year (DALY) averted. Screening was most cost-effective among PLHIV. Among persons with clinical and structural risk factors there was limited evidence, but screening was generally not shown to be cost-effective. CONCLUSIONS: Studies showed that screening is most likely to be cost-effective in a high TB prevalence population. Our review highlights that to reach the "missing millions" TB programmes should focus on simple, cheaper initial screening tools (i.e., symptom screen and CXR) followed by molecular diagnostic tools (i.e., Xpert®) among the highest risk groups in the local setting (i.e., PLHIV, urban slums). Programmatic costs greatly impact cost-effectiveness thus future research should provide both fixed and variable costs of screening interventions to improve comparability.

Seven-year retrospective study understanding the latent TB infection treatment cascade of care among adults in a low incidence country.

BACKGROUND: Prevention of TB is paramount to achieving elimination targets as recommended by the World Health Organization's action framework for low incidence countries striving to eliminate TB. Although the rates of TB in Canada are low, understanding the latent TB infection (LTBI) cascade is paramount to identifying gaps in care and treatment barriers, thereby increasing the effectiveness of preventive strategies. The purpose of this study was to examine the LTBI cascade of care and identify barriers to treatment completion in adults referred from primary care to a regional tertiary care TB clinic in Ottawa, Canada. METHODS: Electronic medical records between January 2010 and December 2016 were reviewed retrospectively and an LTBI cascade of care was constructed from The Ottawa Hospital TB clinic and surrounding primary care clinics. A cohort of 2207 patients with untreated LTBI was used to ascertain the associations between demographic and clinical factors for both treatment non-initiation and non-completion using log-binomial univariable and multivariable regression models. RESULTS: Of 2207 patients with untreated LTBI who were seen in the clinic during the study period, 1771 (80.2%) were offered treatment, 1203 (67.9% of those offered) started treatment, and 795 (66.1% of those started) completed treatment. In multivariable analysis, non-initiation of treatment was associated with older age (adjusted risk ratio [aRR] 1.06 per 5-year increase, 95% CI: 1.03-1.08) and female gender (aRR 1.28, 95% CI: 1.11-1.47). Non completion of treatment was associated with referral from the TB Clinic back to the primary care team following initial consult (aRR 1.62, 95% CI: 1.35-1.94) and treatment with the standard of 9 months of Isoniazid (9H) compared to 4 months of Rifampin (4R) (aRR 1.45, 95% CI:1.20-1.74). CONCLUSIONS: LTBI treatment completion was significantly decreased among patients who were referred back to primary care from the TB clinic. The 4R regimen resulted in more people completing LTBI treatment compared to 9H in keeping with a recently published RCT. Improved education, communication, and collaboration between tertiary care TB clinics and primary care teams may improve treatment completion rates and address the TB burden in low incidence communities in Canada.

Resource implications of the latent tuberculosis cascade of care: a time and motion study in five countries.

BACKGROUND: The End TB Strategy calls for global scale-up of preventive treatment for latent tuberculosis infection (LTBI), but little information is available about the associated human resource requirements. Our study aimed to quantify the healthcare worker (HCW) time needed to perform the tasks associated with each step along the LTBI cascade of care for household contacts of TB patients. METHODS: We conducted a time and motion (TAM) study between January 2018 and March 2019, in which consenting HCWs were observed throughout a typical workday. The precise time spent was recorded in pre-specified categories of work activities for each step along the cascade. A linear mixed model was fit to estimate the time at each step. RESULTS: A total of 173 HCWs in Benin, Canada, Ghana, Indonesia, and Vietnam participated. The greatest amount of time was spent for the medical evaluation (median: 11 min; IQR: 6-16), while the least time was spent on reading a tuberculin skin test (TST) (median: 4 min; IQR: 2-9). The greatest variability was seen in the time spent for each medical evaluation, while TST placement and reading showed the least variability. The total time required to complete all steps along the LTBI cascade, from identification of household contacts (HHC) through to treatment initiation ranged from 1.8 h per index TB patient in Vietnam to 5.2 h in Ghana. CONCLUSIONS: Our findings suggest that the time requirements are very modest to perform each step in the latent TB cascade of care, but to achieve full identification and management of all household contacts will require additional human resources in many settings.

How much does TB screening cost? A systematic review of economic evaluations.

BACKGROUND: Systematic screening for TB has been recommended as a method to control TB on a global level; however, this involves significant costs that place a burden on the health system.METHODS: We conducted a systematic review of the existing economic literature on systematic screening for TB to summarise costs, cost-effectiveness and affordability, and the key factors that influence costs and cost-effectiveness. Specific populations of interest included the general population, children and close contacts of TB patients.RESULTS: We identified 21 studies that provided both cost and outcome data on TB screening among the populations of interest. All were from low- and middle-income settings. Studies were heterogenous in the intervention, and included costs and reported outcomes. The incremental cost-effectiveness ratio (ICER) estimates ranged from USD281 to USD698 per disability-adjusted life-year (DALY) averted among the general population, USD619/DALY averted among children and USD372-3,718/DALY averted among close contacts.CONCLUSION: Prevalence of TB among targeted high-risk groups was identified across the majority of studies as a driver of cost-effectiveness. The heterogeneity of the included costs and outcomes across the economic literature for systematic screening suggests a need for standardisation of included cost components and key economic evaluation methods to improve comparability and generalisability of results.