Delta neutrophil index as an early predictor of acute appendicitis and acute complicated appendicitis in adults

BACKGROUND: This retrospective study aimed to evaluate the ability of the delta neutrophil index (DNI) to predict histologically normal appendicitis preoperatively and to differentiate between simple and complicated appendicitis. METHODS: The data from 650 patients were divided into positive and negative appendectomy groups (histologically normal appendicitis). The patients in the acute appendicitis group were further sub-divided into simple and complicated appendicitis groups. RESULTS: The DNI was significantly higher in the positive group than in the negative appendectomy group (0.4 vs. −0.4, p < 0.001) as well as in the complicated group compared with that in the simple appendicitis group (1.2 vs. 0.3, p < 0.001). The DNI independently predicted a positive appendectomy and an acute complicated appendicitis in multivariate logistic regression analysis [odds ratio (OR) 2.62, 95% confidence interval (CI) (1.11~6.16), p = 0.028 and odds ratio (OR) 4.10, 95% confidence interval (CI) (2.94~5.80), p < 0.001]. The optimum cut-off for a positive appendectomy and acute complicated appendicitis were 0.2 [area under curve (AUC) 0.709] and 0.6 (AUC 0.727). CONCLUSIONS: We suggest that obtaining a preoperative DNI is a useful parameter to aid in the diagnosis of histologically normal appendicitis and to differentiate between simple and complicated appendicitis.