Statistical analysis
Data analysis was performed using SPSS (version 20.0; IBM Corp., Armonk, NY, USA). The distribution of data was checked using the Shapiro–Wilk test. Continuous data with a normal distribution were expressed as means ± standard deviation; otherwise, data were expressed as medians with interquartile ranges. Categorical data are presented as counts (%). Differences between groups were examined using the Student’s t-test, Mann–Whitney U test, and chi-square test. Correlations between the differential metabolites and ALT levels were analyzed using Spearman’s correlation coefficient. Multivariate logistic regression was used to assess the association between metabolites and the risk of PeALT. The ability to distinguish between patients with PeALT and PnALT using different metabolites was evaluated using the area under the receiver operating characteristic (ROC) curve (AUC). The level of statistical significance was set at p < 0.05 (two-sided).