A Usefulness of Delta Neutrophil Index(DNI) for Prediction of 28 Day Mortality in Patients with Pneumonia- Induced Sepsis in the Intensive Care Unit

Background: The delta neutrophil index (DNI) represents the immature granulocyte fraction and is determined by subtracting the fraction of mature polymorphonuclear leucocytes from the sum of myeloperoxidase-reactive cells. The DNI has been proposed as a useful prognostic marker of sepsis. This study evaluated the clinical utility of DNI as a predictive marker in patients with pneumonia-induced sepsis in the intensive care unit (ICU). Methods: We conducted a retrospective study of pneumonia-induced sepsis in patients who were admitted to the Kangdong Sacred Heart Hospital’s medical ICUs from. The DNI was measured on three consecutive days after ICU admission. The primary outcome of this study was the 28-day mortality. Results: A total of 227 patients with pneumonia-induced sepsis were included in this study. The 28-day mortality was 20.3% in our study. In univariate analysis, age (p=0.05), DNI 1 (p =0.01), DNI 2(p=0.00), DNI 3(p=0.00), lactic acid(p =0.00) were significantly associated with 28-day mortality. In multivariable analysis, lactate (adj. OR: 0.86, 95% CI: 0.78-0.95, p =0.002) and DNI 3 (adj. OR: 0.94, 95%CI: 0.89-0.99, p = 0.048) were significantly related with 28-day mortality. Patients with higher DNI 3 (≥2.6) showed higher 28-day mortality than patients with lower DNI< 2.6 (67.4% vs 32.6 %; P < 0.001). Using a cutoff value of 2.6%, the sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of the DNI 3 in sepsis were found to be 69%, 73.9%, 77.9%, and 64.1%, respectively. However, age ≥70 group did not show statistically significant difference DNI 1 values between survivor and non survivor group. Conclusion: DNI at 72 hours after ICU admission is a promising prognostic marker of 28-day mortality in patients with pneumonia-induced sepsis in the ICU. However, interpretation of the Delta Neutrophil Index (DNI) in sepsis patients aged 70 and older on the first day of hospitalization should be approached with caution.