Statistical analysis

Categorical variables were compared using the χ² test for proportions and the unpaired t test or analysis of variance (ANOVA) for continuous variables, as appropriate. The linearity of the relationship between two variables was assessed by linear regression analysis, and Pearson’s correlation coefficient was calculated. Differences between the reduction or increase in each marker and the change in HbA1c were compared using Student’s t tests. Further multiple logistic regression analysis was performed to define independent variables that might predict the change in HbA1c. Overall differences between before and after sitagliptin administration were determined using repeated measures ANOVA. All P values <0.05 were considered statistically significant. Results are expressed as the mean ± standard deviation (SD). All analyses were performed using JMP version 10.0.