Assuming an average change in eGFR of 5.2 4.3 ( SD ) mL/min/1 .73 m ( 2 ) per year in untreated patients , 150 patients are needed in each group to detect a 30 % reduction in the rate of kidney function loss between treatment groups with 80 % power , 2-sided = 0.05 , and 20 % protocol violators and/or dropouts .