Construction And Validation Of The Nomogram For Predicting The Risk Of Acute Complicated Appendicitis

Objective:Acute appendicitis is the most common surgical emergency abdomen.Different severity of appendicitis corresponds to different treatments and outcomes.The method for assessing the severity of acute appendicitis is controversial.This retrospective case-control study constructs a nomogram to predict the risk of complicated appendicitis in order to identify complicated appendicitis in a timely manner,to provide a reference for reducing misdiagnosis and underdiagnosis of complicated appendicitis,and to guide the selection of clinical treatment strategies.Methods:A total of 478 patients diagnosed with acute appendicitis from January 2015 to December 2022 at the The Sixth Medical Center of PLA General Hospital were retrospectively collected and used to build a prediction model.A total of 146 patients with acute appendicitis from January 2015 to December 2022 at the 305 Hospital of PLA were also retrospectively collected and used to validate the model.Clinical information of the above patients were collected:age,gender,duration of symptoms,whether vomiting,anorexia,presence of metastatic right lower abdominal pain,degree of rebound pain,body temperature,white blood cell count,percentage of neutrophils,C-reactive protein at admission,and postoperative pathological findings.According to the postoperative pathology,they were classified into complex appendicitis(gangrenous appendicitis and perforated appendicitis)and uncomplicated appendicitis(simple appendicitis and suppurative appendicitis).Statistical analysis was performed,and t-test was applied to the measurement data conforming to normal distribution,and chi-square test was applied to the categorical data.After comparing the data of the two groups,factors with significant differences were identified and included in the multifactorial logistic regression analysis.The high-risk factors affecting the development of acute complicated appendicitis were then screened and a nomogram was established.The nomogram was externally validated with ROC curves,calibration curves and clinical decision analysis.Results:A total of 624 patients who underwent appendectomy were included in the two hospitals.84 patients were finally diagnosed with perforated appendicitis,with a perforation rate of 13.5%.After logistic regression analysis,the results showed that age(OR=1.034,95%CI:1.018-1.049,P<0.001),duration of symptoms(OR=1.027,95%CI:1.017-1.038,P<0.001),body temperature(OR=2.597,95%CI:1.859-3.629,P<0.001),and percentage of neutrophils(OR=1.070,95%CI:1.029-1.113,P=0.001)were independent risk factors for complicated appendicitis.Based on the above risk factors,a nomogram model was developed to predict the risk of complicated appendicitis.The C-index of this model was 0.831(95%CI:0.785-0.877),and the ROC curve showed an AUC of 0.831(95%CI:0.784-0.877),a sensitivity of 0.820,and a specificity of 0.722;the best cut-off value was 132 points.The nomogram had good external validation results with good discrimination;the calibration curve suggested that the predicted probability tended to be consistent with the actual occurrence probability;while the decision curve indicated a large net clinical benefit of the nomogram.Conclusions:Age,duration of symptoms,temperature,and percentage of neutrophils were identified as risk factors for acute complicated appendicitis.The nomogram based on these factors has certain predictive significance for predicting the risk of patients with complicated appendicitis.