STATISTICS Sample Size Calculations The primary end-point is change in GFR/ERPF after 12 weeks of treatment with dapagliflozin or gliclazide, as derived from the inulin/PAH clearance test. Based on literature the investigators used the following calculation to define our sample size: to detect a change in GFR from 89 mL/min to 75 mL/min (16%), SD 13.0 mL/min, assuming α = 0.05 (2-sided testing), a power (1-β) of 90%, the investigators need 19 subjects per group. However, taking into account a maximum dropout percentage of 15%, the investigators have chosen to increase the amount of subjects per group to N=22. This sample size was calculated using Stata-software (v.11.2, College Station, Texas, USA).