ObjectivesTo assess the predictive value of neutrophils-to-lymphocytes ratio (NLR) in the diagnosis of children complicated appendicitis.MethodsThe clinical data of patients with acute appendicitis treated in Department of Pediatric Surgery, the Second Affiliated Hospital of Xi’an Jiaotong University from January 2014 to June 2017 were analyzed retrospectively. Based on the pathology results, patients were divided into two groups: simple appendicitis and complicated appendicitis. The differences of age, gender, disease time, fever, highest temperature, emesis, right lower abdominal pain, blood indicators, and ultrasound results between the two groups were analyzed. Useful parameters to aid in the diagnosis of children complicated appendicitis were screened through single-factor and multiple-factor analysis. The predictive value of the parameters was evaluated by ROC analysis, sensitivity and specificity.ResultsA total of 235 patients was evaluated and divided into simple appendicitis group (179 patients) and complicated appendicitis group (56 patients). Logistic regression analysis revealed that NLR was the independent risk factor for diagnosis of children complicated appendicitis. When NLR>11.74, the Youden index for predictive complicated appendicitis was the biggest, reaching 0.325, and the sensitivity and specificity were 47.8% and 84.7%, respectively (OR=3.121, 95%CI 2.036 to 4.783).ConclusionsThe preoperative NLR is a certain indicator for predicting children complicated appendicitis, and can be used as reference to whether or not receive an operation.