Development of a nomogram for the prediction of complicated appendicitis during pregnancy

Abstract

Abstract Background: Complicated appendicitis during pregnancy directly affects the clinical prognosis of both mother and fetus. However, accurate identification of complicated appendicitis in pregnancy is fraught with various challenges. The purpose of this study was to identify the risk factors and to develop a useful nomogram to predict complicated appendicitis during pregnancy. Methods: This retrospective study involved pregnant women who underwent appendectomy at the Maternal and Child Health Hospital of Hubei Provincial from May 2016 to May 2022 and who ultimately had histopathologically confirmed acute appendicitis. Univariate and multivariate logistic regression were applied to analyze clinical parameters and imaging features as a way to identify risk factors. Then, nomogram and scoring systems predicting complicated appendicitis in pregnancy were constructed and evaluated. Finally, the potential non-linear association between risk factors and complicated appendicitis was analyzed using restricted cubic splines. Results: Three indicators were finally identified for the construction of the nomogram: gestational weeks, CRP, and NEUT%. To improve the clinical utility, the gestational weeks were divided into three periods (first trimesters, second trimesters, and third trimesters), while the optimal cut-offs for CRP level and NEUT% were found to be 34.82 mg/L and 85.35%, respectively. Multivariate regression analysis showed that third trimester (P=0.013, OR=16.81), CRP level ≥34.82 mg/L (P=0.007, OR=6.24) and NEUT% ≥85.35% (P=0.011, OR=18.05) were independent risk factors for complicated appendicitis. The AUC of the nomogram predicting complicated appendicitis in pregnancy was 0.872 (95% CI: 0.803-0.942). In addition, the model was shown to have excellent predictive performance by plotting calibration plots, DCA, and clinical impact curves. When the optimal cut-off point of the scoring system was set at 12, the corresponding AUC, sensitivity, specificity, PLR, NLR, PPV, and NPV values were AUC: 0.869(95% CI: 0.799-0.939),100%, 58.60%, 2.41, 0, 42%, and 100%, respectively. The restricted cubic splines revealed a linear relationship between these predictors and complicated appendicitis during pregnancy. Conclusions: The nomogram utilizes a minimum number of variables to develop an optimal predictive model. Using this model, the risk of developing complicated appendicitis in individual patients can be determined so that reasonable treatment choices can be made.