For discrete and continuous variables, descriptive statistics (mean, standard deviation, median, minimum, and maximum values) were calculated. In addition, the homogeneity of variances, which is one of the prerequisites of parametric tests, was checked using Levene’s test. The assumption of normality was tested using the Shapiro–Wilk test. To compare the differences between the two groups, an independent sample t-test was used when the parametric test prerequisites were fulfilled, and the Mann–Whitney U test was used when such prerequisites were not fulfilled. The chi-squared test was used to determine the relationships between the two discrete variables. When the expected sources were less than 20%, values were determined using the Monte Carlo simulation method to include these sources in the analysis. Age was determined as covariates (to be excluded), and the groups were compared using covariance analysis.
The cutoff points for the parameters were evaluated using receiver operating characteristic (ROC) curve analysis. Area under curve (AUC) of the ROC curve was calculated. We identified the value for each that maximized the Youden index (J), a summary statistic based on receiver operating characteristic curves that equally weights sensitivity and specificity (sensitivity + specificity − 1). The scores were estimated by constructing a multivariable logistic regression model considering the following covariates: NSS score, age, absence of fatigue, CRP, d-dimer, procalcitonin values, lymphocyte, and platelet counts. Due to the study design, we expected potential imbalances between groups. Propensity score matching was used to reduce potential selection bias between appendicitis group and MIS-C group. Data were evaluated using SPPS, version 25 (IBM Statistics, New York, USA). Statistical significance was set at p < 0.05 and p < 0.01.
The cutoff points for the parameters were evaluated using receiver operating characteristic (ROC) curve analysis. Area under curve (AUC) of the ROC curve was calculated. We identified the value for each that maximized the Youden index (J), a summary statistic based on receiver operating characteristic curves that equally weights sensitivity and specificity (sensitivity + specificity − 1). The scores were estimated by constructing a multivariable logistic regression model considering the following covariates: NSS score, age, absence of fatigue, CRP, d-dimer, procalcitonin values, lymphocyte, and platelet counts. Due to the study design, we expected potential imbalances between groups. Propensity score matching was used to reduce potential selection bias between appendicitis group and MIS-C group. Data were evaluated using SPPS, version 25 (IBM Statistics, New York, USA). Statistical significance was set at p < 0.05 and p < 0.01.
