Background: To describe the epidemiology and possible risk factors for the development of multidrug-resistant tuberculosis (MDR-TB) in Namibia.
Methods: Using medical records and patient questionnaires, we conducted a case-control study among patients diagnosed with TB between January 2007 and March 2009. Cases were defined as patients with laboratory-confirmed MDR-TB; controls had laboratory-confirmed drug-susceptible TB or were being treated with WHO Category I or Category II treatment regimens.
Results: We enrolled 117 MDR-TB cases and 251 TB controls, of which 100% and 2% were laboratory-confirmed, respectively. Among cases, 97% (113/117) had been treated for TB before the current episode compared with 46% (115/251) of controls (odds ratio [OR] 28.7, 95% confidence interval [CI] 10.3-80.5). Cases were significantly more likely to have been previously hospitalized (OR 1.9, 95% CI 1.1-3.5) and to have had a household member with MDR-TB (OR 5.1, 95% CI 2.1-12.5). These associations remained significant when separately controlled for being currently hospitalized or HIV-infection.
Conclusions: MDR-TB was associated with previous treatment for TB, previous hospitalization, and having had a household member with MDR-TB, suggesting that TB control practices have been inadequate. Strengthening basic TB control practices, including expanding laboratory confirmation, directly observed therapy, and infection control, are critical to the prevention of MDR-TB.