Endpoints and statistical analysis of the present study
REGRESSION
For the purposes of the present study, a single cohort was done by all the patients enrolled into the CLOCK trial, regardless their clamping approach. The aim of the study was to assess eventual relationships between WIT and the functional results of the procedure. The value of WIT was set as null (WIT = 0) for the off-clamp cases.The functional outcomes were measured by the following endpoints assessed at 6 months after surgery:the absolute variation of eGFR (AV-GFR, continuous variable);the rate of relative variation in eGFR over 25% (RV-GFR > 25, dichotomous variable);the absolute variation in the SRF of the operated kidney at scintigraphy (AV-SRF, continuous variable).The relationships between endpoints and the duration of WIT were here investigated by visual assessment, drawing scatter plots with a nonparametric regression line [Uni- and multivariable regression were then used to model the relationships between WIT and response variables (linear regression for AV-GFR and AV-SRF by estimating regression coefficients [RC]; logistic regression for RV-GFR > 25 by estimating odds ratio [OR]). To account for potential confounders a set of variables defined This analysis was replicated also excluding the off-clamp cohort for which WIT was computed as null.When scatter plots evidenced a nonlinear relationship, a piecewise linear regression function was used in the regression equation; the positions of knots were identified by visual assessment.The distributions of continuous variables were summarized by median and interquartile range (IQR), while for categorical variables the number of observations with percentages (%) were reported. Differences between median values and proportions in subgroups of participants were tested using the Wilcoxon rank-sum test and Fisher’s exact test, respectively.The statistical analyses were performed using Stata version 16.1 (Stata Corp., College Station, TX, USA). Statistical significance was set at 