Relationship between hepatitis C infection and treatment status and COVID-19-related hospitalizations in Georgia.

OBJECTIVE: To evaluate the impact of hepatitis C virus (HCV) infection and treatment status on COVID-19-related hospitalizations in Georgia. METHODS: We analyzed 2020-2021 Georgian health-registry data for COVID-19-positive individuals and categorized by HCV infection and treatment status. Logistic regression was used to assess the strengths of the associations. RESULTS: Treated HCV individuals had lower odds of COVID-19-related hospitalization compared to anti-HCV-negatives, while untreated HCV-viremic and anti-HCV-positive non-viremic individuals had higher odds. CONCLUSIONS: HCV treatment prior to COVID-19 infection was associated with lower odds of COVID-19-related hospitalization, highlighting the benefits of HCV management in the context of the pandemic.

Association of Treated and Untreated Chronic Hepatitis C With the Incidence of Active Tuberculosis Disease: A Population-Based Cohort Study.

BACKGROUND: Hepatitis C virus (HCV) infection causes dysregulation and suppression of immune pathways involved in the control of tuberculosis (TB) infection. However, data on the role of chronic hepatitis C as a risk factor for active TB are lacking. We sought to evaluate the association between HCV infection and the development of active TB. METHODS: We conducted a cohort study in Georgia among adults tested for HCV antibodies (January 2015-September 2020) and followed longitudinally for the development of newly diagnosed active TB. Data were obtained from the Georgian national programs of hepatitis C and TB. The exposures of interest were untreated and treated HCV infection. A Cox proportional hazards model was used to calculate adjusted hazard ratios (aHRs). RESULTS: A total of 1 828 808 adults were included (median follow-up time: 26 months; IQR: 13-39 months). Active TB was diagnosed in 3163 (0.17%) individuals after a median of 6 months follow-up (IQR: 1-18 months). The incidence rate per 100 000 person-years was 296 among persons with untreated HCV infection, 109 among those with treated HCV infection, and 65 among HCV-negative persons. In multivariable analysis, both untreated (aHR = 2.9; 95% CI: 2.4-3.4) and treated (aHR = 1.6; 95% CI: 1.4-2.0) HCV infections were associated with a higher hazard of active TB, compared with HCV-negative persons. CONCLUSIONS: Adults with HCV infection, particularly untreated individuals, were at higher risk of developing active TB disease. Screening for latent TB infection and active TB disease should be part of clinical evaluation of people with HCV infection, especially in high-TB-burden areas.

Impact of Hepatitis C Virus Infection and Treatment on Mortality in the Country of Georgia, 2015-2020.

BACKGROUND: Mortality related to hepatitis C virus (HCV) infection is a key indicator for elimination. We assessed the impact of HCV infection and treatment on mortality in the country of Georgia during 2015-2020. METHODS: We conducted a population-based cohort study using data from Georgia's national HCV Elimination Program and death registry. We calculated all-cause mortality rates in 6 cohorts: (1) Negative for anti-HCV; (2) anti-HCV positive, unknown viremia status; (3) current HCV infection and untreated; (4) discontinued treatment; (5) completed treatment, no sustained virologic response (SVR) assessment; (6) completed treatment and achieved SVR. Cox proportional hazards models were used to calculate adjusted hazards ratios and confidence intervals. We calculated the cause-specific mortality rates attributable to liver-related causes. RESULTS: After a median follow-up of 743 days, 100 371 (5.7%) of 1 764 324 study participants died. The highest mortality rate was observed among HCV infected patients who discontinued treatment (10.62 deaths per 100 PY, 95% confidence interval [CI]: 9.65, 11.68), and untreated group (10.33 deaths per 100 PY, 95% CI: 9.96, 10.71). In adjusted Cox proportional hazards model, the untreated group had almost 6-times higher hazard of death compared to treated groups with or without documented SVR (adjusted hazard ratio [aHR] = 5.56, 95% CI: 4.89, 6.31). Those who achieved SVR had consistently lower liver-related mortality compared to cohorts with current or past exposure to HCV. CONCLUSIONS: This large population-based cohort study demonstrated the marked beneficial association between hepatitis C treatment and mortality. The high mortality rates observed among HCV infected and untreated persons highlights the need to prioritize linkage to care and treatment to achieve elimination goals.

Hepatitis C care cascade among patients with and without tuberculosis: Nationwide observational cohort study in the country of Georgia, 2015-2020.

BACKGROUND: The Eastern European country of Georgia initiated a nationwide hepatitis C virus (HCV) elimination program in 2015 to address a high burden of infection. Screening for HCV infection through antibody testing was integrated into multiple existing programs, including the National Tuberculosis Program (NTP). We sought to compare the hepatitis C care cascade among patients with and without tuberculosis (TB) diagnosis in Georgia between 2015 and 2019 and to identify factors associated with loss to follow-up (LTFU) in hepatitis C care among patients with TB. METHODS AND FINDINGS: Using national ID numbers, we merged databases of the HCV elimination program, NTP, and national death registry from January 1, 2015 to September 30, 2020. The study population included 11,985 adults (aged ≥18 years) diagnosed with active TB from January 1, 2015 through December 31, 2019, and 1,849,820 adults tested for HCV antibodies between January 1, 2015 and September 30, 2020, who were not diagnosed with TB during that time. We estimated the proportion of patients with and without TB who were LTFU at each step of the HCV care cascade and explored temporal changes. Among 11,985 patients with active TB, 9,065 (76%) patients without prior hepatitis C treatment were tested for HCV antibodies, of which 1,665 (18%) had a positive result; LTFU from hepatitis C care was common, with 316 of 1,557 (20%) patients with a positive antibody test not undergoing viremia testing and 443 of 1,025 (43%) patients with viremia not starting treatment for hepatitis C. Overall, among persons with confirmed viremic HCV infection, due to LTFU at various stages of the care cascade only 28% of patients with TB had a documented cure from HCV infection, compared to 55% among patients without TB. LTFU after positive antibody testing substantially decreased in the last 3 years, from 32% among patients diagnosed with TB in 2017 to 12% among those diagnosed in 2019. After a positive HCV antibody test, patients without TB had viremia testing sooner than patients with TB (hazards ratio [HR] = 1.46, 95% confidence intervals [CI] [1.39, 1.54], p < 0.001). After a positive viremia test, patients without TB started hepatitis C treatment sooner than patients with TB (HR = 2.05, 95% CI [1.87, 2.25], p < 0.001). In the risk factor analysis adjusted for age, sex, and case definition (new versus previously treated), multidrug-resistant (MDR) TB was associated with an increased risk of LTFU after a positive HCV antibody test (adjusted risk ratio [aRR] = 1.41, 95% CI [1.12, 1.76], p = 0.003). The main limitation of this study was that due to the reliance on existing electronic databases, we were unable to account for the impact of all confounding factors in some of the analyses. CONCLUSIONS: LTFU from hepatitis C care after a positive antibody or viremia test was high and more common among patients with TB than in those without TB. Better integration of TB and hepatitis C care systems can potentially reduce LTFU and improve patient outcomes both in Georgia and other countries that are initiating or scaling up their nationwide hepatitis C control efforts and striving to provide personalized TB treatment.

Resistance to Mycobacterium tuberculosis Infection Among Household Contacts: A Multinational Study.

BACKGROUND: Some contacts of patients with tuberculosis remain negative on tests for tuberculosis infection, despite prolonged exposure, suggesting they might be resistant to Mycobacterium tuberculosis infection. The objective of this multinational study was to estimate the proportion of household contacts resistant to M. tuberculosis (resisters). METHODS: We conducted a longitudinal study enrolling index patients enrolled in treatment for pulmonary multidrug- or rifampin-resistant tuberculosis and their household contacts. Contacts were tested for tuberculosis infection with a tuberculin skin test (TST) and interferon-gamma release assay (IGRA) at baseline and after 1 year. Exposure was quantified based on index patients' infectiousness, index patient and household contact interaction, and age. We explored multiple definitions of resistance to tuberculosis infection by varying TST negativity cutoffs (0 vs <5 mm), classification of missing test results, and exposure level. RESULTS: In total, 1016 contacts were evaluated from 284 households; 572 contacts aged ≥5 years had TST and longitudinal IGRA results available. And 77 (13%) or 71 (12%) contacts were classified as resisters with a <5 mm or 0 mm TST threshold, respectively. Among 263 highly exposed contacts, 29 (11%) or 26 (10%) were classified as resisters using TST cutoffs of <5 mm and 0 mm, respectively. The prevalence of resisters did not differ substantially by sex, age, human immunodeficiency virus (HIV) coinfection, or comorbid conditions. CONCLUSIONS: At least 10% of household contacts can be classified as resistant to tuberculosis infection, depending on the definition used, including those with high exposure. Further studies to understand genetic or immunologic mechanisms underlying the resister phenotype may inform novel strategies for therapeutics and vaccines.

Hepatitis C prevalence and risk factors in Georgia, 2015: setting a baseline for elimination.

BACKGROUND: The country of Georgia launched the world's first Hepatitis C Virus (HCV) Elimination Program in 2015 and set a 90% prevalence reduction goal for 2020. We conducted a nationally representative HCV seroprevalence survey to establish baseline prevalence to measure progress toward elimination over time. METHODS: A cross-sectional seroprevalence survey was conducted in 2015 among adults aged ≥18 years using a stratified, multi-stage cluster design (n = 7000). Questionnaire variables included demographic, medical, and behavioral risk characteristics and HCV-related knowledge. Blood specimens were tested for antibodies to HCV (anti-HCV) and HCV RNA. Frequencies were computed for HCV prevalence, risk factors, and HCV-related knowledge. Associations between anti-HCV status and potential risk factors were calculated using logistic regression. RESULTS: National anti-HCV seroprevalence in Georgia was 7.7% (95% confidence interval (CI) = 6.7, 8.9); HCV RNA prevalence was 5.4% (95% CI = 4.6, 6.4). Testing anti-HCV+ was significantly associated with male sex, unemployment, urban residence, history of injection drug use (IDU), incarceration, blood transfusion, tattoos, frequent dental cleanings, medical injections, dialysis, and multiple lifetime sexual partners. History of IDU (adjusted odds ratio (AOR) = 21.4, 95% CI = 12.3, 37.4) and blood transfusion (AOR = 4.5, 95% CI = 2.8, 7.2) were independently, significantly associated with testing anti-HCV+ after controlling for sex, age, urban vs. rural residence, and history of incarceration. Among anti-HCV+ participants, 64.0% were unaware of their HCV status, and 46.7% did not report IDU or blood transfusion as a risk factor. CONCLUSIONS: Georgia has a high HCV burden, and a majority of infected persons are unaware of their status. Ensuring a safe blood supply, implementing innovative screening strategies beyond a risk-based approach, and intensifying prevention efforts among persons who inject drugs are necessary steps to reach Georgia's HCV elimination goal.

Risk factors and genotype distribution of hepatitis C virus in Georgia: A nationwide population-based survey.

In preparation for the National Hepatitis C Elimination Program in the country of Georgia, a nationwide household-based hepatitis C virus (HCV) seroprevalence survey was conducted in 2015. Data were used to estimate HCV genotype distribution and better understand potential sex-specific risk factors that contribute to HCV transmission. HCV genotype distribution by sex and reported risk factors were calculated. We used explanatory logistic regression models stratified by sex to identify behavioral and healthcare-related risk factors for HCV seropositivity, and predictive logistic regression models to identify additional variables that could help predict the presence of infection. Factors associated with HCV seropositivity in explanatory models included, among males, history of injection drug use (IDU) (aOR = 22.4, 95% CI = 12.7, 39.8) and receiving a blood transfusion (aOR = 3.6, 95% CI = 1.4, 8.8), and among females, history of receiving a blood transfusion (aOR = 4.0, 95% CI 2.1, 7.7), kidney dialysis (aOR = 7.3 95% CI 1.5, 35.3) and surgery (aOR = 1.9, 95% CI 1.1, 3.2). The male-specific predictive model additionally identified age, urban residence, and history of incarceration as factors predictive of seropositivity and were used to create a male-specific exposure index (Area under the curve [AUC] = 0.84). The female-specific predictive model had insufficient discriminatory performance to support creating an exposure index (AUC = 0.61). The most prevalent HCV genotype (GT) nationally was GT1b (40.5%), followed by GT3 (34.7%) and GT2 (23.6%). Risk factors for HCV seropositivity and distribution of HCV genotypes in Georgia vary substantially by sex. The HCV exposure index developed for males could be used to inform targeted testing programs.

Epidemiology beyond its limits.

In 1995, journalist Gary Taubes published an article in Science titled "Epidemiology faces its limits," which questioned the utility of nonrandomized epidemiologic research and has since been cited more than 1000 times. He highlighted numerous examples of research topics he viewed as having questionable merit. Studies have since accumulated for these associations. We systematically evaluated current evidence of 53 example associations discussed in the article. Approximately one-quarter of those presented as doubtful are now widely viewed as causal based on current evaluations of the public health consensus. They include associations between alcohol consumption and breast cancer, residential radon exposure and lung cancer, and the use of tanning devices and melanoma. This history should inform current debates about the reproducibility of epidemiologic research results.

Long-Term Mortality and Active Tuberculosis Disease Among Patients Who Were Lost to Follow-Up During Second-Line Tuberculosis Treatment in 2011-2014: Population-Based Study in the Country of Georgia.

BACKGROUND: High rates of loss to follow-up (LFU) exist among patients with multidrug and extensively drug-resistant tuberculosis (M/XDR TB). We aimed to identify long-term clinical outcomes of patients who were LFU during second-line TB treatment. METHODS: We conducted a follow-up study among adults who received second-line TB treatment in the country of Georgia during 2011-2014 with a final outcome of LFU. We attempted to interview all LFU patients, administered a structured questionnaire, and obtained sputum samples. Active TB at follow-up was defined by positive sputum Xpert-TB/RIF or culture. RESULTS: Follow-up information was obtained for 461 patients. Among these patients, 107 (23%) died and 177 (38%) were contacted. Of those contacted, 123 (69%) consented to participate and 92 provided sputum samples. Thirteen (14%) had active TB with an estimated infectious time period for transmitting drug-resistant TB in the community of 480 days (interquartile range = 803). In multivariable analysis, positive culture at the time of LFU was associated with active TB at the time of our study (adjusted risk ratio = 13.3; 95% confidence interval, 4.2-42.2). CONCLUSIONS: Approximately one quarter of patients on second-line TB treatment who were LFU died. Among those LFU evaluated in our study, 1 in 7 remained in the community with positive sputum cultures. To reduce death and transmission of disease, additional strategies are needed to encourage patients to complete treatment.

Interim effect evaluation of the hepatitis C elimination programme in Georgia: a modelling study.

BACKGROUND: Georgia has a high prevalence of hepatitis C, with 5·4% of adults chronically infected. On April 28, 2015, Georgia launched a national programme to eliminate hepatitis C by 2020 (90% reduction in prevalence) through scaled-up treatment and prevention interventions. We evaluated the interim effect of the programme and feasibility of achieving the elimination goal. METHODS: We developed a transmission model to capture the hepatitis C epidemic in Georgia, calibrated to data from biobehavioural surveys of people who inject drugs (PWID; 1998-2015) and a national survey (2015). We projected the effect of the administration of direct-acting antiviral treatments until Feb 28, 2019, and the effect of continuing current treatment rates until the end of 2020. Effect was estimated in terms of the relative decrease in hepatitis C incidence, prevalence, and mortality relative to 2015 and of the deaths and infections averted compared with a counterfactual of no treatment over the study period. We also estimated treatment rates needed to reach Georgia's elimination target. FINDINGS: From May 1, 2015, to Feb 28, 2019, 54 313 patients were treated, with approximately 1000 patients treated per month since mid 2017. Compared with 2015, our model projects that these treatments have reduced the prevalence of adult chronic hepatitis C by a median 37% (95% credible interval 30-44), the incidence of chronic hepatitis C by 37% (29-44), and chronic hepatitis C mortality by 14% (3-30) and have prevented 3516 (1842-6250) new infections and averted 252 (134-389) deaths related to chronic hepatitis C. Continuing treatment of 1000 patients per month is predicted to reduce prevalence by 51% (42-61) and incidence by 51% (40-62), by the end of 2020. To reach a 90% reduction by 2020, treatment rates must increase to 4144 (2963-5322) patients initiating treatment per month. INTERPRETATION: Georgia's hepatitis C elimination programme has achieved substantial treatment scale-up, which has reduced the burden of chronic hepatitis C. However, the country is unlikely to meet its 2020 elimination target unless treatment scales up considerably. FUNDING: CDC Foundation, National Institute for Health Research, National Institutes of Health.

Contacts of retreatment tuberculosis cases with a prior poor treatment outcome are at increased risk of latent tuberculosis infection.

OBJECTIVES: To estimate the prevalence of and risk factors for latent tuberculosis infection (LTBI) among contacts of index patients with tuberculosis (TB) with a prior history of active TB disease and TB treatment (retreatment cases). METHODS: A cross-sectional population-based study was conducted using data from the national TB contact surveillance program in the country of Georgia. Contacts of retreatment cases were investigated and tuberculin skin testing was offered. Bivariate and multivariable analyses were performed to calculate odds ratios (OR) and 95% confidence intervals for risk of LTBI among contacts. RESULTS: The prevalence of LTBI was significantly higher among contacts whose index TB patient had had a prior unfavorable treatment outcome compared to those who had had a favorable outcome (OR 3.14). Contacts whose index TB case had previously failed therapy (OR 6.43), was lost to follow-up (OR 5.63), or had completed treatment (OR 3.33) had a significantly higher prevalence of LTBI compared to contacts of previously cured TB cases. CONCLUSIONS: Among contacts of active TB retreatment cases, the risk of LTBI was related to the outcome of the index case's previous TB treatment. Efforts aimed at reducing treatment loss to follow-up should be emphasized to enhance TB control efforts and may also decrease LTBI and active TB among contacts.