Treatment of Latent Tuberculosis Infection (LTBI) with Isoniazid (INH) and Rifapentine (RPT): Is It a Better Option?

BACKGROUND:  Treatment of latent tuberculosis (TB) infection (LTBI) is essential to controlling and eliminating TB in the United States, because it substantially reduces the risk that TB infection will progress to TB disease.  Tarrant County Public Health (TCPH) has traditionally adopted the recommended 9-month isoniazid regimen for LTBI treatment.  This strategy, however, is compromised by low levels of treatment adherence and treatment completion rates.   The primary objective of this project was to determine and compare the percentage of patients who completed the 12–dose regimen of Isoniazid (INH) and Rifapentine (RPT).

METHODS: The 12–dose regimen of INH and RPT was offered to all eligible Contacts of an active TB case, Homeless Shelter Residents and Refugees beginning January 1, 2014.  All clients were medicated via Directly Observed Preventive Therapy (DOPT); most by delivery of the medications by the outreach staff and the others were provided enablers (bus pass) to come to the TCPH TB clinic for the medication.  Those missing doses were followed up with regarding reasons for missed doses, and Homeless Shelter Residents were flagged in the Homeless Management Information System (HMIS) to contact the TB Clinic when doses were missed.  All data pertaining to this project was maintained in a database created for case management of patients on the treatment regimen.

RESULTS:  Between January 1, 2014 and September 30, 2014, 220 eligible patients were offered and accepted the 12-dose regimen of INH and RPT. The overall treatment completion rate was 77.8% - of the 220 patients, 171 completed the recommended treatment regimen.  The highest treatment completion rates were seen among the Contacts (92%) followed by the Refugees (89%) and the Homeless Shelter Residents (51%).   

CONCLUSIONS: The goal of TB elimination can be accomplished by treating LTBIs effectively.  Identifying barriers to adherence and adopting strategies for maximizing adherence are fundamental in addressing the current problems facing LTBI programs and their clients.