Neutrophil to Lymphocyte Ratio as a Marker in the Diagnosis and Prediction of Acute Appendicitis

Acute appendicitis is one of the most common surgical emergencies. The role of the neutrophils to lymphocytes ratio in diagnosing appendicitis is debatable. For this, this study aimed to investigate the diagnostic value of neutrophils to lymphocytes ratio to diagnose acute appendicitis. In the case–control method designed for this study, a total of 505 candidates for appendicitis surgery from July 2020 to July 2021 in Bojnurd City (eastern north of Iran) were investigated. Inclusion criteria were age 15–75, and the patients should have pathology results for their diagnosis. The exclusion criteria were acute infection in the last week, history of blood transfusion, and history of chronic autoimmune disease. The clinical history and symptoms, laboratory tests, sonography evidence, and CT scans of participants before surgery were gathered. The appendix pathology was evaluated by a pathologist after surgery, and two groups of pathology results were approved appendicitis and no approved appendicitis. Collected variables were analyzed through a t-test or Mann–Whitney test, and logistic regression was used to remove possible confounders; diagnostic accuracy was performed using receiver operating curve analysis. The result of the study showed that 273 (54.3%) of the participants were male and 260 (67.3%) were residents of the city. Sixty-seven point three percent (67.3%) of the patients had nausea and vomiting; the tenderness and shift of pain to the right were reported in 481 (94.4%) and 359 (71.2%) of them, respectively. The mean ± standard deviation age of patients was 31.1 ± 12.6. The mean and standard deviation of neutrophils to lymphocytes ratio in non-appendicitis were 7.5 ± 6.1 and in acute appendicitis were 3.5 ± 3.3, and there was a significant difference between the two groups (p-value < 0.0001). In the cut point of 3.76 for the neutrophil to lymphocyte ratio, the receiver operating curve area was 0.78 (95% CI 0.75, 0.82), and for this criteria, the sensitivity was 0.74.3 (95% CI 69.4, 78.7), and specificity was 0.74.65 (95% CI 66.5, 81.7). In the final model of logistic regression, the odds ratio of male gender was 1.7 (95% CI 1.05, 2.65), leukocyte counts 1.00023 (95% CI 1.0005, 1.00003), abdominal pain shift to the right 1.82 (95% CI 1.15, 2.98), and neutrophils to lymphocytes ratio 1.72 (95% CI 1.05, 2.65), and there were as predictors of acute appendicitis. It is evident that the neutrophil to lymphocyte ratio (NLR) is a valuable marker for diagnosing acute appendicitis. Furthermore, when combined with male gender, high leukocyte count, and right-sided abdominal pain, the NLR becomes an effective set of predictors for this condition.