Abstract
Background: Current eligibility criteria for urine lateral-flow-lipoarabinomannan assay (LF-LAM) in ambulatory, HIV-positive patients rely on the CD4 count. We investigated the diagnostic yield of LF-LAM and the 6-month mortality in ambulatory, TB symptomatic, HIV-positive patients regardless of their CD4 count.
Methods: We conducted a prospective, observational study that included all ambulatory, >15-year-old, TB symptomatic (cough, weight loss, fever, or night sweats) HIV-positive patients presenting at 4 health facilities in Malawi. Patients received a clinical examination and were requested urine LF-LAM, sputum microscopy and Xpert MTB/RIF. TB was defined as bacteriologically confirmed if Xpert was positive.
Results: Of 485 patients included, 171 (35.3%) had a CD4<200 and 32 (7.2%) were seriously ill. Median CD4 count was 341 cells/µL (IQR: 129-256). LAM was positive in 24.9% patients with CD4<200 (50% LAM Grades 2-4) and 12.5% with CD4≥200 (12.8% LAM Grades 2-4). Xpert was positive in 14.1% (44/312). Among Xpert-positive patients, LAM-positivity was: 56.7% (CD4<200) and 42.9% (CD4≥200), p=0.393. Of the patients without an Xpert result, 13.4% (23/172) were LAM-positive (i.e. potentially missed patients). Overall mortality was 9.2% (44/478). More pronounced LAM-positive patients had higher mortality than LAM-negative (Grades 2-4: 36.0%; Grade 1: 9.1%; Negative: 7.4%; p<0.001). LAM-positive patients with CD4<200 cells/µL had higher risk of mortality than LAM-negatives (aHR:3.2, 95CI:1.4-7.2, p=0.006), particularly those with LAM Grades 2-4 (aHR:4.9, 95CI:1.8-13.3, p=0.002).
Conclusions: Urine-LAM testing can be useful for TB diagnosis in HIV-positive TB-symptomatic patients with no CD4 cell count. LAM grade can identify patients at higher risk of death in this situation.
