Increasing multidrug-resistant tuberculosis in Ho Chi Minh City: a retrospective study of 2,266 cases from 2011 to 2015

Background: Multidrug resistant tuberculosis (MDR-TB) remains a serious public health problem with poor treatment outcome. Predictors of poor outcomes vary in different regions. Vietnam is among the 30 countries with high burden of MDR-TB. We aim to describe demographic characteristics and identify risk factors for poor outcome of MDR-TB in Ho Chi Minh City (HCMC), the most populous city in Vietnam. Methods: This retrospective study included 2,266 patients who initiated MDR-TB treatment from 2011 to 2015 in HCMC. Treatment outcomes were available in 2,240 patients. Data was collected from standardized paper-based treatment cards and electronic records. Kruskal Wallis test was used to diagnose the change of median of age and body mass index (BMI) over 5 years, and Wilcoxon test to compare median BMI of patients with and without diabetes mellitus. Chi squared test was used to compare categorical variables. Multivariate logistic regression on multiple imputation was used to identify risk factors for poor outcomes. Statistical analysis was performed using R program. Results: Among 2,266 eligible cases, 60.2% were failure of category I or II regimen, 57.7% were underweight, 30.2% had diabetes mellitus and 9.6% were HIV positive. Notification rate increased 24.7% from 2011 to 2015.Treatment success rate was 73.3%. Risk factors for poor treatment outcome included HIV co-infection (adjusted odds ratio (aOR): 2.94), advanced age (aOR: 1.45 for every increase of 5 years for patients 60 years or older), having history of MDR-TB treatment (aOR: 5.53), sputum smear grade scanty and 1+ (aOR: 1.47), smear grade 2+ or 3+ (aOR: 2.06), low BMI (aOR: 0.83 for every increase of 1kg/m2 of BMI for patients with BMI<21). Conclusion: Our study describes the increasing cases of MDR-TB in HCMC during 2011 to 2015. Patients with HIV, high smear grade, malnutrition and history of previous MDR-TB treatment should receive additional care. Keywords: multidrug resistant tuberculosis; retrospective; treatment outcome; risk factors; Vietnam