D-index as a Predictor of Complications of Febrile Neutropenia in Patients With Acute Myeloid Leukemia

Acute myeloid leukemia (AML) is highly malignant neoplasm responsible for a large number of cancer-related deaths. It continuously shows 2 peaks in occurrence in early childhood and later adulthood. With an incidence of 3.7 per 100,000 persons per year.

Neutropenia, defined as the absolute neutrophil count (ANC) below 500 cells/ μL or ANC expected to drop below 500 cells/ μL in the next 48 h, represents a potentially fatal complication and is associated with a high risk of developing bacterial infections. Fever is defined as having a bodily temperature above 38.3 ˚C, measured orally, or two measurements above 38 ˚C that are taken at different time points, at least an hour apart.

Concomitance of severe neutropenia (≤ 500 cells/ μL) with high fever (≥ 38.3˚C) is called febrile neutropenia (FN) by the definition of the Infectious Diseases Society of America (IDSA).

Invasive fungal infection (IFI) and bacterial blood stream infection (BSI) consideded a major complications during AML treatment and associated with high morbidity and mortality. Immunosuppression caused by chemotherapy and prolonged hospitalizations expose AML patients to life threatening infections, which can be sustained by multi-drug resistant organisms (MDROs), accounting for one of the major causes of mortality.

A clinical parameter that evaluates the dynamics of neutropenia, combining intensity and duration, could be a good tool to identify patients at high risk for infection. This tool could be used to stratify patients, helping clinicians to select appropriate antibiotics and antifungal therapy in persistently febrile neutropenic patients. An index (called the D-index) that uses data from WBC counts and combines intensity and duration of neutropenia.