Statistical analysis

We compared and analyzed the general and injury-related characteristics between the intentional and unintentional ingestion groups. The mean with standard deviation and median with 25th and 75th percentiles were expressed as the continuous variables. The number of patients and percentage were expressed as the noncontinuous variables. For items requiring statistical verification, an independent T-test and Mann-Whitney U test were used for the continuous variables. A chi-squared test was used for the noncontinuous variables. Using cross-analysis and average comparison, we selected the variables that showed significant differences between the two groups, and based on the researchers’ discretion, we selected the variables considered as factors for hospital admission and mortality. Multiple logistic regression using backward stepwise selection (likelihood ratio) was performed, and the remaining variables with p-value less than 0.05 were listed in the table. The statistics program Statistical Package for the Social Sciences Statistics for Windows version 21 (International Business Machines Corporation, Armonk, NY, USA) was used, and 95% confidence intervals were considered statistically significant.