Identifying risk factors associated with death among patients with MDR-TB in KwaZulu-Natal, South Africa: an illustration using Weibull parametric model

Abstract Background This study aim was to identify the risk factors associated with multidrug-resistant tuberculosis (MDR-TB) disease. The Weibull model has shown to perform better than the Cox proportional models with respect to the accuracy and efficient of the estimates. Therefore, a Weibull parametric model was employed to identify predictors of death in patients with MDR-TB and the efficiency of the models using current dataset. Methods Patients diagnosed with MDR-TB were studied in four decentralised sites located in rural areas and one centralised hospital in KwaZulu-Natal, South Africa from July 2008 to July 2012. Patients were followed from the date of MDR-TB diagnosis until death or the last follow-up date. Results A total of 1 542 patients were included in the analyses: 812 and 730 from the centralised hospital and decentralised sites, respectively. Of the 1 542 enrolled, 15.9% patients died. We found that the hazard of death was significantly higher among patients treated in decentralised sites (aHR) = 1.84, 95% CI = 1.38 – 2.75; SE = 0.81 than that of those who were treated in the centralised hospital. However, the results from the Cox PH model showed an insignificant hazard of death between the decentralised sites and the centralised hospital (aHR = 1.46, 95% CI = 0.69 – 2.36; SE = 0.92). Patients who are between 31 – 40 years of age had increased hazard of death compared to those between 18 – 30 years (aHR = 1.52, 95% CI = 1.04 - 2.23). The hazard of death in female patients was 24% higher compared to male patients (aHR = 1.24, 95% CI = 0.93 - 1.63). Furthermore, patients with previous MDR-TB episodes had an increased hazard of death (aHR = 1.79, 95% CI = 0.23 – 0.62) compared to those with no previous MDR-TB episodes. The hazard of death in HIV negative patients was low compared to those who were HIV positive (aHR = 0.95, 95% CI = 0.57 – 0.77). Conclusion More health facilities are needed especially in decentralised places and that can help the 2030 World Health Organisation strategy to reduce or end TB infection.