D‐index as a marker of bloodstream infections in patients with allogeneic hematopoietic stem cell transplantation

Abstract

Neutropenia is a risk factor for development of infections, however, the direct effect of neutropenia on development of bloodstream infection (BSI) is not known. D‐index, which is area between the neutrophil time curve and a neutrophil count of 0.5 x 10⁹/L, incorporates the combined effect of severity and duration of neutropenia. We aimed to evaluate whether D‐index can be used as a marker for BSI in patients with allogeneic stem cell transplantation. We conducted a retrospective cohort study of patients undergoing allogeneic stem cell transplantation between January 1, 2005, and September 30, 2015. The primary outcome measure was the development of BSI within 30 days of transplantation. A total of 714 patients were included in the study of whom 101 developed BSI. Patients with BSI had a significantly higher median D‐index value compared with patients who did not have BSI (4,990 versus 3,570, P<.001). As a marker, the performance of the D‐index was similar to that of the duration of profound neutropenia (P=0.18) and significantly better than the total duration of neutropenia (P=0.001). The D‐index performed better than the total duration of neutropenia as a marker for BSI in patients with allogeneic stem cell transplantation. There was no difference between D‐index and, a more easily calculable indicator, duration of profound neutropenia.