Prevalence and factors associated with isoniazid mono-resistance and multi-drug resistance among new tuberculosis patients in Kampala.

Abstract

The cornerstone of TB management is at least a 6-month course of a combination of first line drugs. The increasing frequency of anti-TB drug resistance has been a major setback. It is necessary that we prevent further development of the resistance strains and optimize the available first line drugs or TB will become once again incurable. Because Isoniazid continues to have a prominent role in treatment regimens for TB disease and for LTBI, it is essential to understand what factors may be contributing to its resistance so that clinicians can make informed treatment decisions when evaluating these patients. Objectives To determine the prevalence and factors associated with INH mono-resistance and Multi-drug resistance among the new tuberculosis patients attending the CWRU-MU Research collaboration clinic between 2002- 2012 in Kampala District. Methods This study involved two study designs; a baseline cross-sectional and a case-control study nested in an established KCHS cohort from the CWRU-MU Research Collaboration. New TB cases who had attended the clinic between January 2002 and December 2012 were considered. Cases had at least INH mono-resistance and controls had INH susceptible TB, in a ratio of 1 to 3. Factors associated with INH resistance at a level of p< 0.2 were considered for multivariate analysis. Results A total of 962 patients were considered for the prevalence study. INH mono-resistance prevalence was 5.2% (95% CI 3.8 – 6.6) and MDR 0.9 % (95% CI 0.3 – 1.5). Among the 204 case-control patients, the Bantu with aOR of 0.37 (95% CI 0.13- 1.01) and the employed 2.37 (95% CI 1.05- 5.38) were associated with INH mono-resistance. HIV status of an individual was not associated with INH mono-resistance, aOR 1.03 (95% CI 0.44 – 2.42). Conclusion The prevalences of INH resistance and MDR TB are relatively low and have not changed significantly over time in Kampala. Neither INH resistance nor MDR TB was associated with HIV infection. Only the employed and Bantu tribe were associated with INH mono-resistance. Molecular epidemiological studies to assess the genetic disparities among the Ugandan tribes need to be carried in order to identify the different genetic markers.