Statistical analysis
Descriptive statistics included means (95% Confidence Interval) as
appropriate for continuous variables and frequency for categorical
variables. All analyses were performed with SPSS software version 21 and
Microsoft Excel version 2013. Data elaboration, based on the comparison
between two groups (IEI+ and IEI-) differing in the presence/absence of
a previously diagnosed IEI, aimed to:
Assess statistical significance (p-value<0.05) of a difference
between the groups, through chi-squared tests for frequency and Student
t-test for mean.
Describe the correlation (p-value<0.05) between variables
within a group, through Pearson correlation coefficient.