by Christina Yoon, Adithya Cattamanchi, J. Lucian Davis, William Worodria, Saskia den Boon, Nelson Kalema, Winceslaus Katagira, Sylvia Kaswabuli, Cecily Miller, Alfred Andama, Heidi Albert, Pamela Nabeta, Christen Gray, Irene Ayakaka, Laurence Huang
The clinical impact of Xpert MTB/RIF for tuberculosis (TB) diagnosis in high HIV-prevalence settings is unknown. Objective
To determine the diagnostic accuracy and impact of Xpert MTB/RIF among high-risk TB suspects. Methods
We prospectively enrolled consecutive, hospitalized, Ugandan TB suspects in two phases: baseline phase in which Xpert MTB/RIF results were not reported to clinicians and an implementation phase in which results were reported. We determined the diagnostic accuracy of Xpert MTB/RIF in reference to culture (solid and liquid) and compared patient outcomes by study phase. Results
477 patients were included (baseline phase 287, implementation phase 190). Xpert MTB/RIF had high sensitivity (187/237, 79%, 95% CI: 73–84%) and specificity (190/199, 96%, 95% CI: 92–98%) for culture-positive TB overall, but sensitivity was lower (34/81, 42%, 95% CI: 31–54%) among smear-negative TB cases. Xpert MTB/RIF reduced median days-to-TB detection for all TB cases (1 [IQR 0–26] vs. 0 [IQR 0–1], p<0.001), and for smear-negative TB (35 [IQR 22–55] vs. 22 [IQR 0–33], p?=?0.001). However, median days-to-TB treatment was similar for all TB cases (1 [IQR 0–5] vs. 0 [IQR 0–2], p?=?0.06) and for smear-negative TB (7 [IQR 3–53] vs. 6 [IQR 1–61], p?=?0.78). Two-month mortality was also similar between study phases among 252 TB cases (17% vs. 14%, difference +3%, 95% CI: -21% to +27%, p?=?0.80), and among 87 smear-negative TB cases (28% vs. 22%, difference +6%, 95% CI: -34 to +46%, p?=?0.77). Conclusions
Xpert MTB/RIF facilitated more accurate and earlier TB diagnosis, leading to a higher proportion of TB suspects with a confirmed TB diagnosis prior to hospital discharge in a high HIV/low MDR TB prevalence setting. However, our study did not detect a decrease in two-month mortality following implementation of Xpert MTB/RIF possibly because of insufficient powering, differences in empiric TB treatment rates, and disease severity between study phases.