Role of immature granulocyte and blood biomarkers in predicting perforated acute appendicitis using machine learning model.

Background: Acute appendicitis (AAp) is a prevalent medical condition characterized by inflammation of the appendix that frequently necessitates urgent surgical procedures. Approximately two-thirds of patients with AAp exhibit characteristic signs and symptoms; hence, negative AAp and complicated AAp are the primary concerns in research on AAp. In other terms, further investigations and algorithms are required for at least one third of patients to predict the clinical condition and distinguish them from uncomplicated patients with AAp.

Aim: To use a Stochastic Gradient Boosting (SGB)-based machine learning (ML) algorithm to tell the difference between AAp patients who are complicated and those who are not, and to find some important biomarkers for both types of AAp by using modeling to get variable importance values.

Methods: This study analyzed an open access data set containing 140 people, including 41 healthy controls, 65 individuals with uncomplicated AAp, and 34 individuals with complicated AAp. We analyzed some demographic data (age, sex) of the patients and the following biochemical blood parameters: White blood cell (WBC) count, neutrophils, lymphocytes, monocytes, platelet count, neutrophil-to-lymphocyte ratio, lymphocyte-to-monocyte ratio, mean platelet volume, neutrophil-to-immature granulocyte ratio, ferritin, total bilirubin, immature granulocyte count, immature granulocyte percent, and neutrophil-to-immature granulocyte ratio. We tested the SGB model using n-fold cross-validation. It was implemented with an 80-20 training-test split. We used variable importance values to identify the variables that were most effective on the target.

Results: The SGB model demonstrated excellent performance in distinguishing AAp from control patients with an accuracy of 96.3%, a micro aera under the curve (AUC) of 94.7%, a sensitivity of 94.7%, and a specificity of 100%. In distinguishing complicated AAp patients from uncomplicated ones, the model achieved an accuracy of 78.9%, a micro AUC of 79%, a sensitivity of 83.3%, and a specificity of 76.9%. The most useful biomarkers for confirming the AA diagnosis were WBC (100%), neutrophils (95.14%), and the lymphocyte-monocyte ratio (76.05%). On the other hand, the most useful biomarkers for accurate diagnosis of complicated AAp were total bilirubin (100%), WBC (96.90%), and the neutrophil-immature granulocytes ratio (64.05%).

Conclusion: The SGB model achieved high accuracy rates in identifying AAp patients while it showed moderate performance in distinguishing complicated AAp patients from uncomplicated AAp patients. Although the model's accuracy in the classification of complicated AAp is moderate, the high variable importance obtained is clinically significant. We need further prospective validation studies, but the integration of such ML algorithms into clinical practice may improve diagnostic processes.