Assessment of the eligibility for short course treatment regimen of multi-drug resistant tuberculosis in Armenia

Abstract

Tuberculosis (TB) is a major public health issue and according to the World Health Organization (WHO) is one of the top 10 causes of death. In 2016, 10.4 million people had active TB, of which 1.7 million died. Special attention needs multidrug resistant tuberculosis. The treatment of multidrug resistant (MDR) TB is challenging. Its long duration of about 20 months is associated with high cost, greater incidence of adverse reactions, and high rate of lostto follow up. Therefore, the finding of shorter, more effective, lower-cost treatments for MDRTB remains a priority. During the last years, promising results came from observational studies conducted in Bangladesh and 9 African countries, where a 12 months or less regimen for MDR-TB treatment was tested. The short course regimen showed higher success rate with a lower proportion of patients being lost to follow and reduction of cost per patient. In 2016, based on the evidence assessment of the short course treatment regimen effectiveness, WHO included the use of a 9–12 months regimen in the MDR-TB treatment policy as a conditional recommendation. The conditions included not being resistant to any component of the regimen, not having been treated for drug resistant TB in the past, and not being pregnant, etc. Armenia is a high MDR-TB burden country, with only about half of cases finishing treatment successfully. The low success rate reflects the high proportion of lost to follow ups, which is unfortunately constantly increasing. The introduction of a shorter treatment regimen in Armenia could have positive impact on reduction of proportion of defaulters and as a result the increase of success rates. However, before implementation of the new treatment regimen, an evaluation of its applicability in certain geographical areas and the impact of the new approach on the national tuberculosis program is needed. According to the WHO recommendations, the MDR-TB short course treatment should be started as soon as possible based on the genotypic drug susceptibility testing results, which allows identifying the resistance only to isoniazid, fluoroquinolones and injectable drugs. The empiric use of the short course regimen in a population with the high resistance rate to other components of the treatment regimen such as clofazimine, ethio/prothionamide, pyrazinamide and ethambutol will substantially reduce its success rate and will increase drugs resistance. Therefore, assessing the resistance pattern of MDR-TB in Armenia is needed to understand the appropriateness of the new recommendation to this region. In Armenia, the majority of patients with MDR-TB was already being treated for TB, which is an exclusion criterion for short course regimen. Therefore, an estimation of the eligible patients based on the retrospective data can help to understand the impact of the new approach on the programmatic level of the National Tuberculosis program. The evaluation of the poor and successful outcome rates of the patients who could have been eligible for the short course regimen will help to estimate the added value of the new approach. In addition, to predict the course of treatment after implementation of the new regimen, an assessment of factors which are likewise associated with the poor outcome should be performed.