Delta Neutrophil Index as a Predictive Factor of Prolonged Hospitalization in Emergency Department Patients with Acute Pyelonephritis

ABSTRACT

PURPOSE: The delta neutrophil index (DNI) corresponds to evaluated immature granulocyte counts and severity of sepsis. The aim of this study was to investigate the diagnostic value of DNI as a predictable laboratory marker for prolonged hospitalization in patients with acute pyelonephritis in the emergency department (ED). METHODS: We retrospectively analyzed medical records in two EDs and screened eligible adult patients who were admitted to the ED with acute pyelonephritis from July 2012 to July 2014. The DNI was calculated for all patients as a part of routine complete blood analysis, and diagnostic performance of DNI for predicting prolonged hospitalization (over 14 days) in patients with acute pyelonephritis (APN) was evaluated. RESULTS: A total of 308 patients with APN were enrolled in the study. Among them, 89 patients (29.9%) were hospitalized for more than 14 days. The initial DNI value was significantly higher in patients with more than 14 days of hospitalization than in those with less than 14 days of hospitalization (6% vs. 2%, p<0.001). The peak value of DNI was also significantly higher in patients discharged after 14 days of hospitalization than in those discharged before 14 days (8% vs. 2%, p<0.001). Multivariate Cox proportional hazard models showed that a DNI of more than 6.3 on ED admission day (hazard ratio [HR], 0.314; 95% confidence interval [CI], 0.191-0.515, p<0.001) and on peak day (HR, 0.37; 95% CI, 0.244-0.562, p=0.028) was an independent risk factor for hospitalization over 14 days. CONCLUSION: DNI is potentially useful as an independent factor for predicting hospitalization for more than 14 days.