Latent Tuberculosis Cascade of Care Among Healthcare Workers: A Nationwide Cohort Analysis in Korea Between 2017 and 2018

BACKGROUND

In 2017, Korea implemented nationwide latent tuberculosis infection (LTBI) project targeting healthcare workers (HCWs). We aimed to assess its performance using the cascade of care model.

METHODS

We included 45,503 employees of medical institutions with positive interferon-gamma release assay result who participated between March 2017 and December 2018. We described percentages of LTBI participants completing each step in the cascade of care. Poisson regression model was conducted to assess individual characteristics and factors associated with not-visiting clinics for further care, not-initiating LTBI treatment, and not-completing treatment.

RESULTS

Proportions of visiting clinics and initiating and completing treatment in HCWs were 54.9%, 38.5%, and 32.0%, respectively. Despite of less likelihood of visiting clinics and initiating LTBI treatment, older age ≥ 65 years were more likely to complete treatment (adjusted relative risk [aRR], 0.80; 95% confidence interval [CI], 0.64-0.99), compared to young age < 35 years. Compared to nurses, doctors were less likely to visit clinic; however, were more likely to initiate treatment (aRR, 0.88; 95% CI, 0.81-0.96). Those who visited public health centers were associated with not-initiating treatment (aRR, 1.34; 95% CI, 1.29-1.40). When treated at private hospitals, 9-month isoniazid monotherapy was less likely to complete treatment, compared to 3-month isoniazid and rifampicin combination therapy (aRR, 1.33; 95% CI, 1.16-1.53).

CONCLUSION

Among employees of medical institutions with LTBI, only one third completed treatment. Age, occupation, treatment center, and initial regimen were significantly related to LTBI treatment performance indicators. Rifampicin-based short treatment regimens were effective under standard of care.

The cascade of care for latent tuberculosis infection in congregate settings: A national cohort analysis, Korea, 2017-2018

Background

In 2017, Korea implemented a nationwide project to screen and treat latent tuberculosis infection (LTBI) in high-risk for transmission public congregate settings. We aimed to assess programme success using a cascade of care framework.

Materials and methods

We undertook a cohort study of people from three congregate settings screened between March 2017 and December 2018: (1) first-grade high school students, (2) employees of educational institutions, (3) employees of social welfare facilities. We report percentages of participants with LTBI completing each step in the cascade of care model. Poisson regression models were used to determine factors associated with not visiting clinics, not initiating treatment, and not completing treatment.

Results

Among the 96,439 participants who had a positive interferon-gamma release assay result, the percentage visiting clinics for further assessment, to initiate treatment, and who then completed treatment were 50.7, 34.7, and 28.9%, respectively. Compared to those aged 20-34 years, individuals aged < 20 years and aged ≥ 65 years were less likely to visit clinics, though more likely to complete treatment once initiated. Using public health centres rather than private hospitals was associated with people "not initiating treatment" (adjusted risk ratio [aRR], 3.72; 95% confidence interval [CI], 3.95-3.86). Nine-month isoniazid monotherapy therapy was associated with "not completing treatment," compared to 3-month isoniazid and rifampin therapy (aRR, 1.28; 95% CI, 1.16-1.41).

Conclusion

Among participants with LTBI from three congregate settings, less than one third completed treatment. Age, treatment centre, and initial regimen were important determinants of losses to care through the cascade.

Current situation of tuberculosis and National Strategic Plan for Tuberculosis Control in Korea

Tuberculosis (TB) remains a serious public health problem in Korea. Korea has the highest incidence rate (59 per 100,000 population) and the second-highest TB mortality rate (four per 100,000 population) among Organisation for Economic Cooperation and Development member countries. However, some progress has been made in TB control over the past decade. The notification rate of new TB cases has been gradually decreasing since reaching its highest rate in 2011 (78.9 per 100,000 population). In 2019, the notification rate of new TB cases was 46.4 per 100,000 population, with a reduction of 9.9% from the 2018 rate. Additionally, the number of multidrug-resistant TB cases decreased from 618 in 2018 to 580 in 2019. This progress is thought the result of various TB control programs including a TB public–private mix model, insurance coverage for TB management, and a contact investigation program. Despite the progress made, new challenges have also emerged. The predominant challenges lie in the relatively increasing burden of TB in the vulnerable population (aging, socio-economically vulnerable, and foreign-born population), the implementation of latent TB infection management, and the high rate of multidrug-resistant TB. Since 2019, the Korean government has been implementing the “Midterm strategies to strengthen TB prevention and management” based on the 2nd National Strategic Plan for Tuberculosis Control (2018-2022). This program will be a turning point of TB control in Korea. The results produced in 2023 is expected to be favorable.

Tuberculosis Surveillance and Monitoring under the National Public-Private Mix Tuberculosis Control Project in South Korea 2016-2017

BACKGROUND

The national Public-Private Mix (PPM) tuberculosis (TB) control project provides for the comprehensive management of TB patients at private hospitals in South Korea. Surveillance and monitoring of TB under the PPM project are essential toward achieving TB elimination goals.

METHODS

TB is a nationally notifiable disease in South Korea and is monitored using the surveillance system. The Korea Centers for Disease Control and Prevention quarterly generates monitoring indicators for TB management, used to evaluate activities of the PPM hospitals by the central steering committee of the national PPM TB control project. Based on the notification date, TB patients at PPM hospitals were enrolled in each quarter, forming a cohort, and followed up for at least 12 months to identify treatment outcomes. This report analyzed the dataset of cohorts the first quarter of 2016 through the fourth quarter of 2017.

RESULTS

The coverage of sputum, smear, and culture tests among the pulmonary TB cases were 92.8% and 91.5%, respectively. The percentage of positive sputum smear and culture test results were 30.7% and 61.5%, respectively. The coverage of drug susceptibility tests among the culture-confirmed cases was 92.8%. The treatment success rate among the smear-positive drug-susceptible cases was 83.2%. The coverage of latent TB infection treatment among the childhood TB contacts was significantly higher than that among the adult contacts (85.6% vs. 56.0%, p=0.001).

CONCLUSION

This is the first official report to analyze monitoring indicators, describing the current status of the national PPM TB control project. To sustain its effect, strengthening the monitoring and evaluation systems is essential.

Latent tuberculosis infection screening and treatment in congregate settings (TB FREE COREA): protocol for a prospective observational study in Korea

INTRODUCTION

South Korea regards tuberculosis (TB) incidence in congregate settings as a serious problem. To this end, systematic latent TB infection (LTBI) diagnosis and treatment were provided to approximately 1.2 million individuals in high-risk congregate settings.

METHODS AND ANALYSIS

We designed a prospective cohort study of individuals tested for LTBI, based on the data collected on all persons screened for LTBI as part of the 2017 congregate settings programme in South Korea. Four types of databases are kept: LTBI screening database (personal information and LTBI test results), national health information (NHI) database (socio-demographic data and comorbidities), public healthcare information system (PHIS) database, and the Korean national TB surveillance system database (TB outcomes). Information regarding LTBI treatment at private hospitals and public health centres is collected from NHI and PHIS databases, respectively. The screening data are cleaned, duplicates are removed, and, where appropriate, re-coded to analyse specific exposures and outcomes. The primary objective is to compare the number of active TB cases prevented within 2 years between participants undergoing treatment and not undergoing treatment in the LTBI screening programme in congregate settings. Cascade of care for LTBI diagnosis and treatment will be evaluated among those with a positive LTBI test result. A Cox proportional hazards model will be applied to determine the risk factors for developing active TB.

ETHICS AND DISSEMINATION

The protocol is approved by the institutional review boards of Incheon St. Mary's Hospital, the Catholic University of Korea. Study results will be disseminated through peer-reviewed journals and conference presentations.

TRIAL REGISTRATION NUMBER

KCT0003905.