Determinants of MDR-TB in a district tuberculosis centre of a metropolitan city: A case - control study

Abstract

Background: Multidrug resistant tuberculosis (MDR-TB) is of growing health concern globally and in India. MDR-TB is defined as Mycobacterium tuberculosis resistant to Isoniazid and Rifampicin. The current prevalence of MDR-TB in India is 2.3% (ranging from1.8%-2.8%)and 17.2% (ranging from 14.9%-19.5%) among newly diagnosed and previously treated cases respectively. Increased cost, more side effects and longer duration of treatment makes MDR-TB management a great challenge.Methods & Materials: The present study was conducted as an Unmatched Case Control study to identify the determinants of MDR-TB. The study was conducted in all the 14 Tuberculosis units (TU) of Revised National Tuberculosis Control Programme (RNTCP) under the Municipal Corporation of Bengaluru. The source of the study subjects were patients registered under 14 TUs during the period of January 2013 to June 2014, with 52 MDR-TB patients as Cases and 53 non MDR-TB patients as Controls. Cases and controls were confirmed by culture and drug susceptibility test done at the Intermediate Reference Laboratory (IRL), Bengaluru. Both cases and controls were interviewed at their residence using a pretested semi structured questionnaire.Results: Univariate analysis including descriptive statistics along with Chi-square test and multivariate logistic regression were used to analyse the data. The mean age of the cases was 38.5 ± 15.8 years which was almost similar to that of the controls (38.5 ± 13.0 years). Univariate analysis revealed -the number of previous episodes of TB, type of health setup approached during the first episode of TB, treatment outcome of the first episode of TB, Gender, employment status, religion, education and socioeconomic status as statistically significant determinants of MDR-TB. After adjusting for potential confounders with multivariate logistic regression -the number of previous episodes of TB (OR = 4.08, 95%CI: 1.53-10.86), the treatment outcome of the first episode of TB(OR = 2.15, 95%CI: 1.42-3.25) and gender (OR = 3.14, 95%CI: 1.18-8.29) were found to be independent determinants of MDR-TB. Conclusion:Hence prompt treatment of newly diagnosed cases of tuberculosis in the first instance is critical in prevention of MDR-TB. Adequate counselling regarding treatment adherence to the patients at the first episode of TB will ensure compliance and reduce the chances of drug resistance.