O1-20-6 - Development and Evaluation of an Index That Predicts Pulmonary Fungal Infection in Patients with Febrile Neutropenia

Abstract

Purpose: Prolonged and profound neutropenia is the high risk to develop invasive fungal infections. Although the cumulative D-index (c-D-index) is useful for the determination of the risk of pulmonary infection in patients with neutropenia, calculation of this index requires a great deal of time and effort. We propose herein an index (G-index: granulocyte index) which could be calculated quickly and easily, and predict a pulmonary fungal infectious disease in neutropenic patients.Patients and methods: We retrospectively examined the impact of the G-index in 20 patients with hematological malignancy who developed neutropenia duration over 7 days. We defined possible, probable and proven infection cases as invasive pulmonary fungal infection patients. The G-index approximate to the area over the neutrophil curve during neutropenia. The G-index is obtained by the formula: 2t1 + 3t2, where t1 is the days from start of neutropenia less than 500/microliter until the development of infection, and t2 is the days from start of neutropenia less than 100/microliter until the development of infection. We compared the G-index with c-D-index, and determined a cutoff value for invasive fungal infection using the receiver operating characteristic curve (ROC) analysis.Results: The G-index and c-D-index showed equal high accuracy performance, the areas under the curves of the ROCs were 0.931 and 0.922 with no statistical significant difference (p-value 0.699). For cutoff points of 45 and 5344 of the G-index and the c-D-index, the sensitivity and specificity for predicting pulmonary fungal infections were 75.0%, 75.0% and 93.1%, 96.6% and the positive and negative predictive values were 75.0%, 85.7% and 93.1%, 93.3% for a prevalence 21.6%.Conclusion: Using G-index, risk stratification of pulmonary fungal infection in febrile neutropenic patients could be performed quickly and easily.