Performance Of Xpert (R) Mtb/Rif And Determine (Tm) Tb-Lam Ag In Hiv-Infected Adults In Peri-Urban Sites In Zambia

Setting: Peri-urban health facilities providing HIV and TB care in Zambia.Objective: To evaluate 1) the impact of Xpert (R) MTB/RIF on time-to-diagnosis, treatment initiation, and outcomes among adult people living with HIV (PLHIV) on anti-retroviral therapy (ART); and 2) the diagnostic performance of Xpert and Determine (TM) TB-LAM Ag assays.Design: Quasi-experimental study design with the first cohort evaluated per standard-of-care (SOC; first sputum tested using smear microscopy) and the second cohort per an algorithm using Xpert as initial test (intervention phase; IP). Xpert testing was provided onsite in Chongwe District, while samples were transported 5-10 km in Kafue District. TB was confirmed using mycobacterial culture.Results: Among 1350 PLHIV enrolled, 156 (15.4%) had confirmed TB. Time from TB evaluation to diagnosis (P = 0.018), and from evaluation to treatment initiation (P = 0.03) was significantly shorter for IP than for SOC. There was no difference in all-cause mortality (7.0% vs. 8.6%). TB-LAM Ag showed higher sensitivity with lower CD4 cell count: 81.8% at CD4. 50 cells/mm(3) vs. 31.7% overall.Conclusion: Xpert improved time to diagnosis and treatment initiation, but there was no difference in all-cause mortality. High sensitivity of Determine TB-LAM Ag at lower CD4 count supports increased use in settings providing care to PLHIV, particularly with advanced HIV disease.