Performance of the beta-glucan test and a dynamic prediction rule to identify patients in the ICU at high risk to develop candidemia

Introduction

Early initiation of antifungal therapy (AFT) improves the outcome in candidemic patients, but empiric AFT is not considered the standard of care.

Methods

We used a scoring system based on the presence of a central venous catheter and receipt of antibiotics, plus at least two of the following: dialysis, surgery, pancreatitis, and receipt of corticosteroids, other immunosuppressive agents or parenteral nutrition. Different from the original description of the score which considered only the first 7 days of ICU stay, we selected patients who fulfilled these criteria at any time during the ICU stay. Once a patient fulfilled these criteria, AFT (anidulafungin 200 mg followed by 100 mg daily) was initiated provided that the patients also presented with any of the following: fever, hypothermia, hypotension, leukocytosis, acidosis or elevated C-reactive protein. Blood cultures (days 1 to 2) and baseline serum BDG (days 1 to 3) were performed. Patients with candidemia were treated for ≥14 days, those without candidemia but ≥1 positive BDG (≥80 pg/ml) received AFT for ≥10 days, and patients with negative blood cultures and negative BDG discontinued anidulafungin.

Results

A total of 2,148 patients were screened, and 85 (4%) fulfilled entry criteria. The incidence of candidemia in these 85 patients was 8.2%, compared with 0.5% in the remaining 2,063 patients (relative risk 16.9%, 95% confidence interval (CI) = 6.63 to 43.55). Baseline BDG was positive in 74 patients (87%), with a median number of positive tests of 3 (range 1 to 3) and a median value of 523 pg/ml (range 83 to 6,860). All seven patients with candidemia had positive baseline BDG (median value 523 pg/ml, range 203 to 3,660). The best cutoff of baseline BDG for the diagnosis of candidemia was 522 pg/ml (area under the ROC curve 0.883, 95% CI = 0.769 to 0.997), with sensitivity and specificity of 86% and 88%, respectively. The cutoff value of 80 pg/ml had sensitivity and specificity of 73% and 27%, respectively.

Conclusion

This dynamic prediction rule was able to differentiate a group of ICU patients at high risk to develop candidemia, with a relative risk of 16.9. BDG is frequently positive in ICU patients. A cutoff value of 522 pg/ml was able to discriminate between candidemic and noncandidemic patients. A revision of the cutoff value for BDG in the ICU is needed.