Diagnostic Value of Systemic Immune Inflammation Index in Identifying Complicated Acute Appendicitis Cases

Systemic immune inflammation index (SII) has been used to evaluate the prognosis of various diseases in recent years. This study aimed to investigate the efficacy of SII in the preoperative diagnosis of complicated acute appendicitis (CAA).

The data of patients who underwent surgery for acute appendicitis (AA) between January 2021 and December 2023 at our clinic were retrospectively analyzed. These patients had undergone surgical operations for AA and had available pathology results. Cases with histopathologic findings of gangrenous appendicitis, phlegmonous appendicitis, perforated appendicitis, and periappendicular abscesses were considered CAA. Cases without these manifestations and reported as appendicitis upon histopathological analysis were considered as noncomplicated acute appendicitis(NCAA). Data recorded and evaluated for the study included age, sex, preoperative C-reactive protein (CRP) levels, white blood cell (WBC) count, neutrophil count, lymphocyte count, platelet count, neutrophil-to-lymphocyte ratio (NLR), Alvarado score (AS), SII, and histopathologic examination results.

A total of 441 patients were included in the study. The mean age of the patients was 34.58 ± 11.70 years. There were 200 women (45.35%) and 241 men (54.65%). The number of noncomplicated and complicated cases was 332 (75.28%) and 109 (24.72%), respectively. SII, AS, NLR, and CRP values were significantly higher in the complicated group (p < 0.001, p < 0.001, p < 0.001, p = 0.001, respectively). The sensitivity and specificity of SII in detecting CAAs were 0.624 and 0.607, respectively, with a cutoff value of 1445.

The sensitivity of SII in detecting CAA was 0.624, with specificity and cutoff values of 0.607 and 1445, respectively. SII can be used as an effective parameter for preoperatively predicting whether an AA case is complicated or not.