2.5. Statistical analysis
Data were analyzed by Statview 5.0J. Wilcoxon’s
rank-sum test was used to compare the two treatment
groups within the cohort for ordinal and numerical
K. Endo et al. / Diabetes Research and Clinical Practice 71 (2006) 156–163 157
variables, and x2
-test was used in the comparison of
categorical variables. The hemodialysis-free survival
curves were estimated by Kaplan-Meier method [24].
The difference between two survival curves was tested
by the Mantel test [25]. All data were expressed as
mean S.D. A p-value less than 0.05 were considered
to be statistically significant.