Comparison of active tuberculosis case finding strategies for immigrants in South Korea: Epidemiology and cost-effectiveness analysis.

BACKGROUND: Tuberculosis (TB) is one of the serious infectious diseases in South Korea, with 49 new cases per 100,000 people and 629 multi-drug resistant (MDR) cases reported in 2020. TB is increasing among immigrants in S. Korea, and various TB case finding strategies are being performed for screening. We compared active case finding (ACF) with passive case finding (semi-PCF) across epidemiological characteristics and investigated a cost-effective strategy for screening immigrants for TB. METHODS: ACF driven by non-governmental organizations and semi-PCF as part of the government's visa renewal process using CXR with additional acid-fast bacilli (AFB) smear and cultures were performed. Epidemiological parameters were compared between the two TB screening projects, and costs were collected. Cost-effectiveness was evaluated using a decision analysis model from the health system perspective. The primary outcome was incremental cost-effectiveness ratio (ICER) per averted TB case. Additional probabilistic sensitivity analysis was conducted. RESULTS: ACF (2.02%) showed a higher TB prevalence rate than semi-PCF (0.67%) on CXR. For subjects older than 60 years, the suspected TB rate on CXR was significantly higher in ACF (36.6%) than in semi-PCF (12.2%) (P<0.01). TB incidence among the family visa type was significantly higher in ACF (1.96%) than in semi-PCF (0.88%) (P < 0.0012). Costs for ACF ($666.92) were $20.784 higher than for semi-PCF ($646.13), but TB progression decreased by 0.02, resulting in an ICER of $948.18 per averted TB case. In sensitivity analysis, the indirect costs of ACF and semi-PCF had the highest impact on ICER. CONCLUSION: ACF found more TB cases than semi-PCF through CXR screening, and suspect cases with old age and family visa type were more common in ACF than in semi-PCF. ACF is cost-effective as a TB screening strategy for immigrants.

COVID-19 Disease Burden Related to Social Vulnerability and Comorbidities: Challenges to Tuberculosis Control.

Purpose: The first coronavirus disease (COVID-19) spike and subsequent pandemic in South Korea were rapid and disruptive. Government response measures for disadvantaged groups against infectious disease should be prioritized based on evidence and affordability. We investigated whether COVID-19 infection, intensive care unit (ICU) care, and mortality from COVID-19 are related to social and medical vulnerability, including tuberculosis (TB). Patients and Methods: Using the National Health Insurance Service COVID-19 database in South Korea, we analyzed 129,128 patients, including controls, from 1 January to 30 May 2020, during the early stage of the COVID-19 epidemic. The relationship between health insurance premiums (representing socioeconomic status), the Charlson comorbidity index (CCI) score for the severity of the underlying disease, and additional TB diagnosis was analyzed using the chi-square test and logistic regression. Results: For the demographics, 3244 out of 51,783 men (6.3%) and 4836 out of 77,345 women (6.3%) were infected with Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2). COVID-19 infection, ICU care, and mortality were related to older age (p < 0.001) and lower health insurance premium levels (p < 0.05). Regarding the CCI score, the CCI score, COVID-19 infection, and mortality increased (p < 0.0001). In terms of premium level, the highest group showed a lower risk of infection (OR 0.52, 0.48-0.57, p = 0.004), ICU care (OR 0.59, 0.46-0.75, p < 0.001), and mortality (OR 0.51, 0.32-0.78, p = 0.016) than the medical aid group. TB was related to ICU care for COVID-19 (OR 4.27, 1.27-14.38, p = 0.018). Conclusion: In the early epidemic, SARS-CoV-2 infection, ICU admission, and mortality from COVID-19 increased in socioeconomically and physically vulnerable groups. However, the relationship between tuberculosis, COVID-19 and mortality was not definite because of the possible under-reporting of TB cases and the relatively small number of TB patients.

The Relationship Between Socio-Demographic Factors and Tuberculosis Mortality in the Republic of Korea During 2008-2017.

The Republic of Korea has a high incidence of tuberculosis (TB) and TB-specific mortality rate. In 2019, it had the second highest TB-specific mortality among Organization for Economic Co-operation and Development countries. Understanding the factors associated with TB-specific deaths may help eradicate the disease. Therefore, we aimed to identify the general characteristics associated with TB-specific mortality among Koreans. Using Causes of Death Statistics data from Statistics Korea, we assessed the year of death, sex, age, occupation, area of residence, marital status, and education level reported between 2008 and 2017. Patient characteristics associated with TB-specific deaths were analyzed using the Chi-squared test, while influencing factors of TB-specific mortality were analyzed using logistic regression analysis to calculate adjusted odds ratios (AOR). Female (AOR: 0.509, 95% CI: 0.493-0.526), those with a graduate degree or higher (AOR: 0.559, 95% CI: 0.474-0.660) had lower TB-specific mortality rates than those of their counterparts. Conversely, those aged ≥70 years (AOR: 1.239, 95% CI: 1.199-1.280), single (AOR: 1.355, 95% CI: 1.315-1.396), and skilled agricultural, forestry, and fishery workers (AOR: 1.441, 95% CI: 1.359-1.529) had higher TB-specific mortality rates than those of their counterparts. In conclusion, TB-specific mortality rates differed according to the characteristics of the deceased patients. In order to establish effective TB control, multisectoral action on broader determinants should be strengthened.