2.5. Statistical Analysis
Statistical analysis was performed using SPSS 17.0 program (SPSS Inc, Chicago, IL, USA). Numerical variables were expressed as mean ± standard deviation, and categorical variables as numbers and percentages. The normal distribution of the data was evaluated with the Kolmogorov-Smirnov test. When comparing numerical variables, Student’s t-test was used for normally distributed data, and the Mann-Whiney U test for those that did not show a normal distribution. The chi-square and Fisher’s exact tests were used in the analysis of categorical data. Univariate and multivariate logistic regression analyses were conducted to determine the relationship between hydronephrosis and possible clinical variables. The multivariate logistic regression analysis was applied to variables with a p value of <0.1 in the univariate logistic regression analysis. A value of p < 0.05 was considered statistically significant in all comparisons.