Risk factors and treatment outcomes of drug-resistant tuberculosis among patients attending Ndola teaching hospital in Ndola, Zambia: a retrospective case control study

Abstract

Introduction: multidrug-resistant tuberculosis (MDR-TB) defined as resistance to isoniazid and rifampicin, has become a major threat to the control of TB across the globe. This study aimed to determine the risk factors and treatment outcomes of Drug-resistant tuberculosis (DR-TB) patients attending Ndola Teaching Hospital (NTH) in Ndola, Zambia. Methods: we conducted a case control study among DR-TB patients treated at NTH from 2018 - 2020. Medical records of selected MDR-TB cases and drug susceptible TB controls were included. Treatment outcomes of MDR-TB patients were recorded. The multivariable logistic regression was used to evaluate associations between risk factors and MDR-TB infection. Odds ratios and their 95% confidence intervals were reported. Results: the mean age for the study was 36.67±9.94, and males were the majority 156(70.9%). Those with HIV were 123(55.9%), and contact with DR-TB patients were 61(27.7%). A total of 110 cases and 110 controls were selected for this study. The multivariable logistic regression model indicated a strong association between a family size of 1-5 and occurrence of MDR-TB (aOR (adjusted odds ratio): 1.44, 95% CI (confidence interval), 0.74-2.79; p=0.028*). There was also a strong association between contact with TB patient and MDR-TB (aOR: 1.67, 95% CI 0.56-4.92, p=0.033*). The analysis indicated that living in the rural area had a negative association with MDR-TB development (aOR: 0.42, 95% CI 0.19- 0.91, p=0.025*). There was also a negative association between history of previous treatment and developing MDR-TB (aOR: 0.32, 95% CI 0.17-0.61, p<0.001*), as well as that between contact with MDR-TB patient and MDR-TB development (aOR: 0.50, 95% CI 0.16-1.52, p=0.010*). The study further found that of the 110 MDR-TB patients treated, 73.6% had a successful treatment outcome, and 26.4% had an unsuccessful treatment outcome. Conclusion: the study found that smaller family size and contact with TB patients were significant risk factors for developing MDR-TB, while living in rural areas, having a history of previous TB treatment, and contact with MDR-TB patients were negatively associated with its occurrence. A notable proportion of unsuccessful treatment outcome of some cases underscores the need for strengthened patient-centered care, adherence support, and equitable access to healthcare across both rural and urban settings.