Systemic inflammatory indices and age-dependent severity in acute appendicitis: a retrospective cohort study.

Background: Acute appendicitis (AA) remains the most common cause of emergency abdominal surgery, yet achieving precise preoperative risk stratification is still challenging, particularly among elderly patients. Recent interest has focused on systemic inflammatory biomarkers and the role of immunosenescence in influencing disease progression. Materials and methods: We retrospectively analyzed 407 adult patients who underwent appendectomy over a six-year period at a tertiary hospital. Patients were grouped by age and histopathological subtype. Preoperative blood counts were used to calculate systemic inflammatory indices, including NLR, PLR, SII, SIRI, and AISI. Associations between biomarkers and histopathological severity were assessed using multivariable multinomial logistic regression, with adjustments for age and hospitalization duration. Results: Higher neutrophil counts and elevated PLR were significantly associated with gangrenous appendicitis (p < 0.001 and p = 0.047, respectively). Increased SIRI and neutrophil levels predicted phlegmonous appendicitis (p = 0.020 and p < 0.001). Age independently correlated with more severe histopathological forms. Distinct variations in inflammatory profiles were observed across different age groups and histological categories. Conclusion: Systemic inflammatory indices, particularly NLR, PLR, SII, and SIRI, hold considerable promise for enhancing preoperative stratification in acute appendicitis. Their integration into clinical practice could improve diagnostic accuracy, especially in older patients affected by immunosenescence.