Rifampin monoresistant tuberculosis (RMR-TB) is increasingly identified because of scale-up of rapid molecular tests. The longitudinal association of RMR-TB, multidrug-resistant TB (MDR-TB), and HIV/AIDS is incompletely described.
We examined clinical characteristics and treatment outcomes of patients with RMR-TB, isoniazid monoresistant TB (IMR-TB), MDR-TB, and drug-susceptible TB during a 16-year period (1993–2008) in California. TB cases were cross-matched with the state HIV/AIDS registry, and HIV prevalence denominators modeled using nonparametric backcalculation.
Of 42 582 TB cases, 178 (0.4%), 3469 (8.1%), and 635 (1.5%) were RMR-TB, IMR-TB, and MDR-TB, respectively. From the pre-HAART (1993–1996) to HAART (2005–2008) era, RMR-TB rates declined rapidly (12.0 vs. 0.5 per 100 000) among patients with HIV infection. The proportion of patients for whom rifampin resistance indicated RMR-TB (rather than MDR-TB) decreased from 31% [95% confidence interval (CI) 26–38%] to 11% (95% CI 5–19%). In multivariate analysis controlling for HIV coinfection and other covariates, patients with RMR-TB were twice as likely to die as patients with drug-sensitive TB (relative risk 1.94, 95% CI 1.40–2.69).
RMR-TB/HIV rates declined substantially over time in association with improved TB control and HIV control in California. Mortality among patients with RMR-TB was high, even after adjusting for HIV status.