Background: The concentration of the fungal cell wall component β-D-glucan (βG) in blood has been proposed as a useful biomarker for the diagnosis of invasive fungal infections. However, the diagnostic performance of the assay and the clinical significance of βG positivity have not been adequately investigated in patients with candidemia.
Methods: In this single-center retrospective cohort study, we included consecutive candidemic inpatients (first episodes only) with βG measurements within 3 days of the first day of candidemia, who received antifungal treatment between 12/2006 and 12/2012. We compared clinical characteristics and outcomes between patients with serum βG ≥80 (‘positive') and <80 pg/mL (‘negative').
Results: βG levels within 3 days of candidemia were available for 118 of 302 candidemia episodes. Forty-nine (42%) were caused by C. albicans. The sensitivity of βG for candidemia was 67% (95% confidence interval [CI] 59-75%). Intensive Care Unit (ICU) stay (adjusted odds ratio [aOR] 4, 95% CI 1.4-11.6; P=0.01) and C. albicans fungemia (aOR 2.7, 95% CI 1.1-6.5; P=0.02) were independently associated with βG positivity. Specifically, the sensitivity of βG was 86% (95% CI 75-98%) for candidemia in ICU patients and 80% (95% CI 69-91%) for patients with C. albicans fungemia, but 59% (95% CI 48-70%) for non-ICU patients and 58% (95% CI 46-69%) for non-albicans candidemia. There were no differences in time to initiation of any or appropriate (based on in-vitro susceptibilities) antifungal treatment between patients with positive and negative βG. Patients with candidemia and positive βG had a >3-fold higher risk of in-hospital death (43% vs. 13%, P=0.001). βG positivity was an independent predictor of increased 28-day all-cause mortality (Figure – adjusted hazards ratio 3.1, 95% CI 1.1-9.1; P=0.04) and in-hospital death (aOR 4.6, 95% CI 1.4-15.4; P=0.01).
Conclusion: The utility of β-D-glucan for diagnosis and management of candidemia may be limited in non-ICU patients and in settings of high non-albicans Candida species prevalence. In patients with candidemia, βG positivity is associated with poor clinical outcomes.
A. Liakos, None
A. E. Woolley, None
N. C. Issa, None
S. P. Hammond, None
F. M. Marty, None
L. R. Baden, None
S. Koo, None