Prognostic Value of the Delta Neutrophil Index for Predicting 28-Day Mortality in Intensive Care Unit Patients with Candidemia

Abstract

Candidemia is associated with substantial mortality in critically ill patients, and early identification of patients at increased risk of death remains challenging. The delta neutrophil index (DNI), an automated hematological parameter reflecting circulating immature granulocytes, has been proposed as a prognostic marker in sepsis, but its role in candidemia remains unclear. This retrospective study included adults who developed candidemia during intensive care unit hospitalization between January 1, 2020, and December 31, 2023; patients with neutropenia, haematological malignancy receiving ongoing chemotherapy, or granulocyte colony-stimulating factor therapy were excluded. Patients were classified as survivors or non-survivors according to 28-day all-cause mortality after blood culture collection. DNI, leukocyte count, C-reactive protein, and procalcitonin were evaluated 24 hours before, at the time of, and 24 hours after blood culture collection. Multivariable logistic regression identified factors independently associated with mortality, and receiver operating characteristic analysis assessed the prognostic performance of DNI. Among 246 patients, 132 survived and 114 died. Non-survivors had higher APACHE II scores and more frequent acute kidney injury. DNI and procalcitonin levels were significantly higher in non-survivors at all three time points. In the primary multivariable model, acute kidney injury, DNI at blood culture collection, and procalcitonin at blood culture collection were independently associated with mortality; the association of DNI was attenuated and no longer statistically significant after further adjustment for Candida species and antifungal therapy. DNI showed limited discrimination, with area under the curve values ranging from 0.608 to 0.625; the highest value was observed at blood culture collection (0.625), with a cutoff of 2.4, 43.0% sensitivity, and 82.6% specificity. DNI may aid mortality risk stratification in candidemia but should not be used as a standalone prognostic marker.