Statistical analysis
Statistical analysis was performed using SPSS 26.0 or R (version 3.6.2).
The χ2 test or Fisher’s exact test was used for comparison of
categorical variables, and Wilcoxon test was used for continuous
variables after normality was explored with the Shapiro-Wilk test.
Sensitivities, specificities, and accuracies in APS diagnosis were
compared in the McNemar test. Youden Index, positive and negative
predictive values (PPV and NPV), and odds ratio (OR) with 95%
confidence interval (95% CI) were also shown. Receiver operating
characteristic (ROC) curves of individual aPL as well as logistic
regression analysis of aPLs profile were used to calculate the area
under the curve (AUC), with 95% CI shown. Associations between aPL
isotype positivity and clinical manifestation in patients with APS were
explored and displayed in 95% CI. Two-tailed values of P less
than 0.05 were considered statistically significant.