A review of management of latent tuberculosis infection (LTBI) in a TB contact tracing service in Cork, Ireland

Abstract

Introduction Latent Tuberculosis Infection (LTBI) is defined as a persistent immune response to previously acquired Mycobacterium Tuberculosis without evidence of active TB. LTBI, whilst being non-contagious, may become active in 10% of those who acquire it over the remainder of their life. Contact tracing amongst those exposed to a person with active TB is a core public health function to identify people with LTBI. Ideally, all patients identified with LTBI should be offered chemoprophylaxis to prevent disease progression. Monitoring of those taking chemoprophylaxis is important to monitor compliance, treatment completion rates and to observe for adverse events. Good communication between primary care and public health services is vital to achieve optimal contact tracing processes and subsequent management of patients identified with LTBI. The aims of this study were: – to determine the rate of detection of LTBI in contact screening in the Cork region during 2014 and 2015; – to assess initiation and completion rates of chemoprophylaxis. Methods This study was a retrospective study conducted in the Department of Public Health, HSE-South, Cork, Ireland. Data was collected from a prospectively managed departmental contact tracing database which was initiated in 2013. Results There were 52 and 66 cases of TB notified in Cork in 2014 and 2015 respectively. 793 contacts were screened in 2015 compared to 289 in 2014, however the percentage of those diagnosed with latent TB remained unchanged (21%). 111 of 166 patients were commenced on chemoprophylaxis in 2015 and 39 of 57 patients in 2014. Thirty-two and 84 patients completed chemoprophylaxis in 2014 and 2015 respectively. The most common reason for non-completion of chemoprophylaxis was side effects from the medication itself. Discussion The number of patients initiating and completing chemoprophylaxis varied over the two-year period. Trends should be further monitored. A national information system on contact tracing and management of LTBI outcomes does not exist in Ireland at present. Access to a robust reporting system would assist with the delivery of effective contact tracing in relation to TB. An electronic health record accessible to all caregivers in primary and secondary care would also be beneficial. Close contact with primary care i.e. GP is important to ensure that everyone is aware of the treatment plan and any ongoing issues that may arise e.g. reaction to medications. Conclusions The high non-completion rate in 2015 probably reflects factors particular to a cohort within this group (young, socialising, domino effect of one discontinuing medication). Access to a robust reporting system is essential to the delivery of effective contact tracing in relation to TB. Limitations This study only includes one area of Ireland. LTBI detection rates identified by contact tracing and outcomes of LTBI management should be estimated nationally and in other HSE areas to compare practices and outcomes with other countries and across different HSE areas. Suggestions for future research A future challenge for public health is how to further convince patients of the benefits of LTBI treatment. Future research should focus on how to provide an integrated health service to maximize uptake and completion of chemoprophylaxis for maximum societal benefit.