Statistical analysis
Results are presented as percentages (%) and means (±SD) or medians and
interquartile range (IQR). Normality was assessed using the
Kolmogorov-Smirnov test. Chi-square and Fisher exact tests were used for
categorical variables while Student t-test or Mann-Whitney U test were
used for quantitative variables as appropriate. Relationships between
continuous variables were assessed using Spearman rank correlation
coefficient analysis and the correlation coefficient (ρ) was calculated.
Univariate analysis was conducted to assess the factors affecting CRP
values in the overall population. Subgroup analysis was performed
separately for patients who presented infectious complications. The
factors analyzed were VO (vs. Non-VO), ERAS (vs. standard
care), male gender (vs.female), CCI >4 (vs. < 4), cancer
(vs. benign disease), extent of resection (right hemicolectomyvs. left hemicolectomy vs. rectal resection), need for
conversion (vs. no conversion), and surgical time >
median (vs. < median). A screened p-value of
<0.10 at univariate analysis was then considered for entering
the multivariate model after validating the absence of
multicollinearity. In multivariate logistic regression, a p value
<0.05 was considered statistically significant.
Since POD3 CRP value is used in our clinical practice as one of the
discharge criteria, we tested it as predictor of infectious
complications by receiver operating characteristic (ROC) curves
analysis. The area under the curve (AUC) is a direct measure of
diagnostic accuracy of a test. A test with an AUC between 0.7-0.8 is
considered as having a good diagnostic accuracy. Cut-off values with the
highest sensitivity and specificity were determined by using the
Youden’s index. To compare accuracy between ROC curves in subgroup
analysis, the DeLong method was applied 14.
Results were considered statistically significant when p value was found
to be <0.05. SPSS software (version 23, SPSS, Inc.) was used
for statistical analysis. Graphics were outlined using GraphPad Prism
version 9.0.