The impact of implementing a Xpert MTB/RIF algorithm on drug-sensitive pulmonary tuberculosis: a retrospective analysis

Xpert MTB/RIF (Xpert) is the preferred first-line test for all persons with tuberculosis (TB) symptoms in South Africa in line with a diagnostic algorithm. This study evaluates pre- and post-implementation trends in diagnostic practices for drug-sensitive, pulmonary TB in adults in an operational setting, following the introduction of the Xpert-based algorithm. We retrospectively analysed data from the national TB database for Greater Tzaneen sub-district, Limpopo Province. Trends in a number of cases, diagnosis and outcome and characteristics associated with death are reported. A total of 8407 cases were treated from 2008 until 2015, with annual cases registered decreasing by 31.7% over that time period (from 1251 to 855 per year). After implementation of Xpert, 69.9% of cases were diagnosed by Xpert, 29.4% clinically, 0.6% by smear microscopy and 0.1% by culture. Cases with a recorded microbiological test increased from 76.2% to 96.4%. Cases started on treatment without confirmation, but with a negative microbiological test increased from 7.1% to 25.7%. Case fatality decreased from 15.0% to 9.8%, remaining consistently higher in empirically treated groups, regardless of HIV status. Implementation of the algorithm coincided with a reduced number of TB cases treated and improved coverage of microbiological testing; however, a substantial proportion of cases continued to start treatment empirically.