Frailty modelling for multidrug-resistant tuberculosis mortality in Namibia

Multidrug-Resistant Tuberculosis (MDR-TB) is fast becoming a major public health concern, with 80% of the reported global MDR-TB deaths occurring in high burden countries including Namibia where drug susceptibility testing is not routinely performed. Previous studies on TB in Namibia have primarily focused on TB and HIV co-infection and MDR-TB development. However, no study to date has specifically examined the epidemiology of MDR-TB mortality or its associated risk factors at a national level. Thus, this study aimed at examining the variation of mortality among MDR-TB patients in Namibia and identifying its risk factors.

The study adopted a retrospective cohort study design using the 2014-2017 MDR-TB records, and a Gompertz PH model with Gamma (shared) frailty for the frailty modelling of the MDR-TB mortality and its associated risk factors.

There were more MDR-TB deaths among females, HIV positive patients with pulmonary TB in the Khomas region. MDR-TB mortality was more likely to occur for patients who were aged 55 and above (HR = 3.57, p < 0.001, 95% CI: 2.18-5.91), HIV positive (HR = 2.07, p < 0.001, 95% CI: 1.39-3.08), and from the Khomas (HR = 3.68, p = 0.001, 95% CI: 1.72-7.87), Kunene (HR = 4.45, p = 0.022, 95% CI: 1.24-15.91), Omusati (HR = 2.70, p = 0.022, 95% CI: 1.15-6.31), and Oshana (HR = 2.51, p = 0.021, 95% CI: 1.15-5.48) regions.

It is therefore recommended that the Namibian government and policy makers consider conducting outreach sessions to increase awareness on MDR-TB including early detection and screening programmes, and patient's adherence, especially among female patients aged 55 and above, with HIV and those living in these highlighted regions.