The D-index is not correlated with invasive fungal infection during the early-post engraftment phase among allogeneic hematopoietic stem cell transplant recipients

The D-index assesses neutropenia dynamics. Prolonged neutropenia is a major risk for invasive fungal infection (IFI); we hypothesized that D-index is predictive of IFI risk. We retrospectively reviewed 789 adults who underwent allogeneic hematopoietic transplant (HSCT) from 1/1/2005 to 9/30/2015. Medical records were reviewed from transplant (D0) through Day 100. The D-index was calculated as area over the neutrophil curve until engraftment. 714 patients were included for analysis. Sixteen (2%) developed probable (11) or proven (5) IFI. Median time to IFI was 40 days (range 8–98) after HSCT. Groups with and without IFI did not differ significantly in duration of mild or profound neutropenia. Median D-index of those with IFI was 4293 days neutrophil/µl compared to 3590 days neutrophil/µl for those without IFI (P = 0.17). Patients who were neutropenic on D0 showed higher rates of IFI than those who were not (10/123 [8%] vs 6/591 [1%]; P < 0.001). Only 2% developed IFI, likely due to mold-active antifungal prophylaxis. The D-index was not significantly higher in those with IFI. Duration of profound neutropenia and neutropenia at D0 may be better markers for IFI among HSCT recipients during the first 30 and 100 days after transplant.