Statistical analysis
For the descriptive analysis, categorical variables were expressed as
absolute and relative frequencies; and quantitative values as mean and
range (minimum-maximum values). Comparisons between ECC and DCC groups
were carried out with the chi-square or Fisher Exact tests for
categorical variables, and t-test or U Mann-Whitney test for
quantitative ones, when appropriate. Statistical significance was
established with P < .05. All statistical analyses were
performed with SAS 9.4.