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Diagnostic accuracy of the rapid urine lipoarabinomannan test for pulmonary tuberculosis among HIV-infected adults in Ghana-findings from the DETECT HIV-TB study.

Bjerrum S, Kenu E, Lartey M, Newman MJ, Addo KK, Andersen AB, Johansen IS - BMC Infect. Dis. (2015)

Bottom Line: A two-sample LAM test strategy did not improve test performance.LAM test sensitivity was highest in patients with poor prognosis and subsequent death and did not increase with a two-sample strategy.A rigorous sputum microscopy strategy had superior sensitivity, but the simplicity of the LAM test holds operational possibilities as a TB screening method among severely sick patients.

View Article: PubMed Central - PubMed

Affiliation: Department of Infectious Diseases, Odense University Hospital, Odense, Denmark. steph@medicinsk.dk.

ABSTRACT

Background: Rapid diagnostic tests are urgently needed to mitigate HIV-associated tuberculosis (TB) mortality. We evaluated diagnostic accuracy of the rapid urine lipoarabinomannan (LAM) test for pulmonary TB and assessed the effect of a two-sample strategy.

Methods: HIV-infected adults eligible for antiretroviral therapy were prospectively enrolled from Korle-Bu Teaching Hospital in Ghana and followed for minimum 6 months. We applied the LAM test on urine collected as a spot and early morning sample. Diagnostic accuracy was analysed for a microbiological TB reference standard based on sputum culture and Gene Xpert MTB/RIF results and for a composite reference standard including clinical follow-up data. Performance of sputum smear microscopy was included for comparison.

Results: Of 469 patients investigated for TB, the LAM test correctly identified 24/55 (44 %) of microbiologically confirmed TB cases. Sensitivity of the LAM test was positively associated with hospitalisation (67 %), Modified Early Warning Score > 4 (57 %) and subsequent death (71 %). LAM test specificity was 95 % increasing to 98 % for the composite reference standard. A two-sample LAM test strategy did not improve test performance. Using concentrated sputum for Ziehl-Neelsen and fluorescence microscopy in combination yielded a sensitivity of 31/55 (56 %) that increased to 35/55 (64 %) when the LAM test was added. Surprisingly, nontuberculous mycobacteria were cultured in 34/469 (7 %) and associated with a positive LAM test (p = 0.008).

Conclusions: LAM test sensitivity was highest in patients with poor prognosis and subsequent death and did not increase with a two-sample strategy. A rigorous sputum microscopy strategy had superior sensitivity, but the simplicity of the LAM test holds operational possibilities as a TB screening method among severely sick patients.

No MeSH data available.


Related in: MedlinePlus

Cumulative probability of survival. a Shown for the full study population (n = 469) by LAM test status. b Shown for confirmed TB cases (n = 55) by LAM test status
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Fig2: Cumulative probability of survival. a Shown for the full study population (n = 469) by LAM test status. b Shown for confirmed TB cases (n = 55) by LAM test status

Mentions: During the study 81 (17 %) of the participants died after a median of 25 days from enrolment. The 6-month mortality was 73 (16 %), 80 (17 %) participants were lost to follow-up (LTFU) and 11 (2 %) transferred out. Confirmed TB patients had a 2-month mortality of 14/55 (25 %) and at 6-month 18 (33 %) cases had died, 7 cases (13 %) were LTFU and 1 (4 %) transferred out. LAM positive participants had a significantly higher probability of death compared to LAM negative in the overall population (p < 0.001) (Fig. 2a) and among “confirmed TB” (p = 0.002) (Fig. 2b). LTFU among LAM positive participants was not significantly higher than among LAM negative (6/45; 18 % vs. 74/424; 13 %, p = 0.5). In a sensitivity analysis assuming that all participants LTFU had died, the probability of death remained significantly higher for LAM-positive than LAM-negative participants overall (p < 0.001) and among confirmed TB cases (p = 0.044).Fig. 2


Diagnostic accuracy of the rapid urine lipoarabinomannan test for pulmonary tuberculosis among HIV-infected adults in Ghana-findings from the DETECT HIV-TB study.

Bjerrum S, Kenu E, Lartey M, Newman MJ, Addo KK, Andersen AB, Johansen IS - BMC Infect. Dis. (2015)

Cumulative probability of survival. a Shown for the full study population (n = 469) by LAM test status. b Shown for confirmed TB cases (n = 55) by LAM test status
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4591579&req=5

Fig2: Cumulative probability of survival. a Shown for the full study population (n = 469) by LAM test status. b Shown for confirmed TB cases (n = 55) by LAM test status
Mentions: During the study 81 (17 %) of the participants died after a median of 25 days from enrolment. The 6-month mortality was 73 (16 %), 80 (17 %) participants were lost to follow-up (LTFU) and 11 (2 %) transferred out. Confirmed TB patients had a 2-month mortality of 14/55 (25 %) and at 6-month 18 (33 %) cases had died, 7 cases (13 %) were LTFU and 1 (4 %) transferred out. LAM positive participants had a significantly higher probability of death compared to LAM negative in the overall population (p < 0.001) (Fig. 2a) and among “confirmed TB” (p = 0.002) (Fig. 2b). LTFU among LAM positive participants was not significantly higher than among LAM negative (6/45; 18 % vs. 74/424; 13 %, p = 0.5). In a sensitivity analysis assuming that all participants LTFU had died, the probability of death remained significantly higher for LAM-positive than LAM-negative participants overall (p < 0.001) and among confirmed TB cases (p = 0.044).Fig. 2

Bottom Line: A two-sample LAM test strategy did not improve test performance.LAM test sensitivity was highest in patients with poor prognosis and subsequent death and did not increase with a two-sample strategy.A rigorous sputum microscopy strategy had superior sensitivity, but the simplicity of the LAM test holds operational possibilities as a TB screening method among severely sick patients.

View Article: PubMed Central - PubMed

Affiliation: Department of Infectious Diseases, Odense University Hospital, Odense, Denmark. steph@medicinsk.dk.

ABSTRACT

Background: Rapid diagnostic tests are urgently needed to mitigate HIV-associated tuberculosis (TB) mortality. We evaluated diagnostic accuracy of the rapid urine lipoarabinomannan (LAM) test for pulmonary TB and assessed the effect of a two-sample strategy.

Methods: HIV-infected adults eligible for antiretroviral therapy were prospectively enrolled from Korle-Bu Teaching Hospital in Ghana and followed for minimum 6 months. We applied the LAM test on urine collected as a spot and early morning sample. Diagnostic accuracy was analysed for a microbiological TB reference standard based on sputum culture and Gene Xpert MTB/RIF results and for a composite reference standard including clinical follow-up data. Performance of sputum smear microscopy was included for comparison.

Results: Of 469 patients investigated for TB, the LAM test correctly identified 24/55 (44 %) of microbiologically confirmed TB cases. Sensitivity of the LAM test was positively associated with hospitalisation (67 %), Modified Early Warning Score > 4 (57 %) and subsequent death (71 %). LAM test specificity was 95 % increasing to 98 % for the composite reference standard. A two-sample LAM test strategy did not improve test performance. Using concentrated sputum for Ziehl-Neelsen and fluorescence microscopy in combination yielded a sensitivity of 31/55 (56 %) that increased to 35/55 (64 %) when the LAM test was added. Surprisingly, nontuberculous mycobacteria were cultured in 34/469 (7 %) and associated with a positive LAM test (p = 0.008).

Conclusions: LAM test sensitivity was highest in patients with poor prognosis and subsequent death and did not increase with a two-sample strategy. A rigorous sputum microscopy strategy had superior sensitivity, but the simplicity of the LAM test holds operational possibilities as a TB screening method among severely sick patients.

No MeSH data available.


Related in: MedlinePlus