The Role of Immature Granulocytes in Predicting Complicated Appendicitis: A Retrospective Observational Study

Differentiating complicated appendicitis (CA) from uncomplicated appendicitis (UA) is a critical aspect of preoperative evaluation that influences surgical planning and patient outcomes. This study explored the role of the immature granulocyte count (IG#) and percentage (IG%) as accessible and reliable biomarkers to enhance the diagnostic precision of CA.

This retrospective observational study analyzed 482 emergency appendectomies performed at a single tertiary hospital between January 2020 and June 2023. After excluding 23 cases due to haematological disorders, malignancies, additional procedures, or incomplete data, 459 patients were included in the final analysis. Patients were categorized into the UA and CA groups based on histopathological examination. CA was defined as a perforation or gangrene. Laboratory parameters, including IG#, IG%, and inflammatory markers, were compared between groups.

Among the 459 patients, 386 (84.1%) had UA and 73 (15.9%) had CA. The median age of CA patients was significantly higher than that of UA patients (36 vs. 33 years, p = 0.016). CA patients also demonstrated significantly elevated levels of C-reactive protein (CRP), direct bilirubin, white blood cell count (WBC), IG#, IG%, and neutrophil-to-lymphocyte ratio (NLR) compared to UA patients (p < 0.001). Receiver operating characteristic (ROC) analysis identified an IG# cut-off of 0.06 (area under the ROC curve [AUROC] = 0.699, sensitivity = 68.5%, specificity = 65.2%) and an IG% cut-off of 0.35 (AUROC = 0.663, sensitivity = 75.3%, specificity = 49.6%). In the multivariable logistic regression analysis, none of the evaluated laboratory parameters, including WBC count (Odds ratio (OR): 1.133, 95% Confidence interval (CI): 0.979-1.313, p = 0.095), IG# (OR: 0.000, 95% CI: 0.000-1.595, p = 0.056), IG% (OR: 6.740, 95% CI: 0.873-52.064, p = 0.067), and NLR (OR: 1.070, 95% CI: 0.980-1.169, p = 0.131), remained significant independent predictors of CA.

Elevated IG# and IG% levels were associated with CA in univariate analysis; however, they did not remain significant independent predictors in the multivariable model. Although the potential of these markers may still provide complementary information in certain clinical scenarios, further large-scale prospective studies are needed to better define their role in clinical practice.