Phase 2 , multicenter , open-label , dose-ranging , randomized clinical trial ( AMETHYST-DN ) , conducted at 48 sites in Europe from June 2011 to June 2013 evaluating patiromer in 306 outpatients with type 2 diabetes ( estimated glomerular filtration rate , 15 to < 60 mL/min/1 .73 m2 and serum potassium level > 5.0 mEq/L ) .