Impact of the D-index deduced from duration and intensity of neutropenia following chemotherapy on the risk of invasive fungal infection in pediatric acute myeloid leukemia.

Pediatric patients with acute myeloid leukemia (AML) are at high risk of invasive fungal infection (IFI). In adult patients, the D-index, which reflects the duration and intensity of neutropenia, was reported as a predictive factor of IFI after induction therapy for AML. The aim of this study was to assess whether the D-index is a predictive factor for IFI in pediatric AML. We define the D-index as the area over the neutrophil curve during neutropenia. Ninety-two courses of chemotherapy performed for 24 consecutive patients with AML undergoing chemotherapy at Sapporo Hokuyu Hospital between April 2007 and March 2017 were analyzed. We also evaluated the utility of the cumulative D-index (c-D-index) from the start of neutropenia until the clinical manifestation of IFI in these patients. The D-index and c-D-index were compared between courses with and without IFI episodes. The median D-index and c-D-index in 6 courses with IFI episodes were 12,816 (range 9500-27,412) and 7250 (range 3987-16,273), respectively, which was not statistically higher than the median D-index [10,127 (range 3788-20,897)] in 86 courses without IFI episodes (P = 0.081 and P = 0.108, respectively). Unlike in adult cases, neither the D-index nor c-D-index reflected the risk of IFI in pediatric AML.