Nationwide and regional incidence of microbiologically confirmed pulmonary tuberculosis in South Africa, 2004-12 : a time series analysis

Abstract

BACKGROUND : South Africa has the highest incidence of tuberculosis in the world, largely resulting from a high population prevalence of HIV infection. We investigated the incidence of microbiologically confirmed pulmonary tuberculosis, and new cases of pulmonary tuberculosis registered for treatment, nationally and provincially in South Africa from 2004 to 2012, during which time there were changes in antiretroviral therapy (ART) coverage among individuals with HIV infection. METHODS : We identifi ed cases of microbiologically confi rmed pulmonary tuberculosis from 2004 to 2012 from the National Health Laboratory Service Corporate Data Warehouse. New cases registered for treatment were identifi ed from National Department of Health electronic registries. A time series analysis, using autoregressive models, was undertaken on incidence of microbiologically confi rmed pulmonary disease nationally and provincially; this trend was also examined relative to ART coverage of adults with HIV infection. FINDINGS : During the 9-year period, 3 523 371 cases of microbiologically confirmed pulmonary tuberculosis were recorded nationally. Annual incidence (per 100 000 population) increased from 650 (95% CI 648–652) in 2004 to 848 (845–850) in 2008, declining to 774 (771–776) by 2012 (9% decrease from 2008 to 2012). Incidence varied by age group, sex, and province. There was an inverse association between incidence of microbiologically confirmed disease and ART coverage among HIV-infected individuals nationally and provincially. Trends in incidence of tuberculosis cases registered for treatment mirrored those of microbiologically confirmed cases nationally and provincially; however, incidence of microbiologically confirmed cases was consistently higher than cases registered for treatment nationally and in seven of nine provinces. INTERPRETATION : Since its peak in 2008, the incidence of microbiologically confirmed pulmonary tuberculosis in South Africa had declined by 2012; this decline is associated with an increase in ART coverage. Future integration of registries for microbiologically confirmed cases and new cases registered for treatment would improve the assessment of the burden of pulmonary tuberculosis in South Africa. FUNDING : National Institute for Communicable Diseases: Division of the National Health Laboratory Service, South Africa.