RECEIVER OPERATING CHARACTERISTIC ANALYSIS AND DISCRIMINATIVE EFFECT OF NEUTROPHIL-TO-LYMPHOCYTE RATIO IN PATIENTS WITH SUSPECTED APPENDICITIS

OZTURK S¹ , UNVER M¹ , YOLDAS O¹ , DIZEN H² , EROL V³ , BOZBIYIK O⁴ ,GUNER M⁵ , PEHLIVANOGLU K⁵ , KEBAPCI E⁵ , AYDIN C⁵ , AKBULUT G⁵

¹ İzmir University Faculty of Medicine, Department of General Surgery -² Eskişehir Yunus Emre State Hospital, Department of General Surgery - ³ Baskent University Faculty of Medicine, Department of General Surgery - ⁴ Ege University Faculty of Medicine, Department of General Surgery - ⁵ Tepecik Education and Research Hospital, Department of General Surgery, Turkey

Introduction: Acute appendicitis (AA) is one of the most common causes of abdominal pain and emergent abdominal surgery. The incidence is approximately 10% during the lifetime. Although appendectomy is a most common surgical procedure worldwide, it’s complication rate is 5-28% A delay in diagnosis of AA is associated with prolonged hospitalization, an increased rate of perforation (34%-75%), wound infection (0%-11%), pelvic abscess (1%-5%) and late intra-abdominal adhesions. Appendectomy is first described by McBurney in 1894 and still remains the standart procedure for AA. Although patients with AA often present with a characteristic symptom complex and physical findings, atypical presentations are common. The aim of this study was to assess the diagnostic value of neutrophil-to-lymphocyte ratio (NLR) in patients who were operated for suspected acute appendicitis and to assess the discriminative effect of this ratio between uninflamed, uncomplicated and complicated appendicitis.

Materials and methods: The medical records of 3212 patients who underwent appendectomy for suspected acute appendicitis during a 10-year period were reviewed retrospectively. Patients were divided into 3 groups; group 1, 208 consecutive patients who had uninflamed appendix at appendectomy; group 2, 2111 consecutive patients who had uncomplicated acute appendicitis at appendectomy; group 3, 893 patients who had complicated appendicitis (perforated appendix or peri-appendicular abscess) at appendectomy. Data for three groups of patients were analyzed to calculate the sensitivity and specificity of the NLR in the diagnosis of acute appendicitis. Receivers operating characteristic (ROC) curves were used to evaluate this ratio in a relation with true diagnosis and severity of acute appendicitis.

Results: 1792 (55.8%) of the patients were male and 1420 (44.2%) of them were female. The mean age of the groups were 30.28±14.18, 29.98 ± 12.63 and 33.81±16.27 respectively. The discriminative effect of NLR was higher between uninflamed and complicated appendicitis groups with a cut-off value of 3,94. The recommended cut-off value of the preoperative NLR was decided using ROC curve analyses. The recommended cut-off value of the NLR was based on the most prominent point on the ROC curve for sensitivity (82.2%) and specificity (56.5%). The area under the ROC curve was 0.74.

Conclusion: AA is one of the most common surgical emergencies and the most common source of infection in communityacquired intra-abdominal infections. However the diagnosis is often challenging and the decision to operate, observe or further work-up on a patient is often unclear. Initial management of patients with suspected AA is based on the history of the patient, physical examination, basic laboratory tests reflecting the inflammatory response and radiologic imaging. NLR is a helpful biochemical parameter for the diagnosis of acute appendicitis but it has limited value on differentiating patients with complicated appendicitis from patients with uninflamed and uncomplicated appendicitis.