The delta neutrophil index is a prognostic factor for postoperative mortality in patients with sepsis caused by peritonitis.

INTRODUCTION: The delta neutrophil index (DNI) represents the fraction of circulating immature granulocytes and is a marker of infection and sepsis. Our objective was to evaluate the usefulness of DNI for predicting in-hospital mortality within 30 days after surgery in patients with sepsis caused by peritonitis by means of comparing DNI, white blood cell (WBC) count, neutrophil percentage, and C-reactive protein (CRP) before and after surgery.

MATERIALS AND METHODS: We performed a retrospective analysis of demographic, clinical, and laboratory data. DNI, WBC count, neutrophil percentage, and CRP were measured before surgery, and at 12-36 h (day 1) and 60-84 h (day 3) after surgery.

RESULTS: There were 116 (73.7%) survivors and 44 (26.3%) non-survivors. The rates of septic shock, norepinephrine administration, renal replacement, mechanical ventilator therapy, and reoperation, the Simplified Acute Physiology Score-3 (SAPS3), and the Sepsis-related Organ Failure Assessment (SOFA) score were greater in non-survivors. DNI on day 3 was better than the other laboratory variables for predicting mortality. DNI was correlated with the SAPS3 (r = .46, p = .00) and SOFA score (r = .45, p = .00). The optimal cut-off DNI for predicting mortality was 7.8% (sensitivity: 77.3%; specificity: 95.9%). In receiver-operating characteristic curve analysis, DNI on day 3 was the best indicator of mortality (area under the curve: .880; 95% confidence interval: .80-.96).

CONCLUSIONS: Our results indicate that DNI is better than other laboratory variables for predicting postoperative mortality in patients with sepsis caused by peritonitis. DNI > 7.8% on day 3 was a reliable predictor of postoperative mortality.