The neutrophil lymphocyte ratio may predict the discharge status in patients admitted to the emergency department

Objective: The neutrophil to lymphocyte ratio (NLR) has been investigated as an indicator of mortality and/or morbidity in many clinical pathologies. However, these studies have mostly been conducted for specific diseases. We investigated whether there is a relationship between the NLR and hospitalization or discharge decisions in the emergency department (ED). Methods: We retrospectively reviewed the medical records of patients admitted to the ED. The NLR values of the patients were calculated, and their demographic characteristics (age and gender) and clinical outcomes were recorded. Results: Of the 1970 patients, 1400 (71.1%) were discharged from the ED, and 570 (28.9%) were hospitalized. The patients who were discharged were younger and had lower NLR values, and this group had a lower female gender ratio (p<0.001, p<0.001, and p<0.001, respectively). The NLR threshold for discharge was 4.8, with a sensitivity of 70% and a specificity of 60%. Of the 570 hospitalized patients, 478 (83.9%) were discharged from the hospital and 92 (16.1%) died. Deceased patients were statistically significantly older with higher NLR values (p<0.001 and p=0.001, respectively). The threshold value of NLR for predicting mortality was calculated as 11.5, with a sensitivity of 45% and a specificity of 77%. Conclusions: Our study reveals that the NLR is an important predictor of hospitalization and mortality in patients admitted to the ED regardless of diagnosis. ED physicians may consider to discharge patients with NLR values below 4.8 instead of spending additional time with advanced tests. In addition, clinicians should review the risk of mortality in patients with NLR values greater than 11.5 more thoroughly concerning mortality and should consider early aggressive treatment options.