Bethenny Frankel revealed that her chronic kidney disease diagnosis has moved into the next stage. "Just left the kidney doctor, he said I actually have stage 3A chronic kidney disease which is right in the middle," Frankel, 55, said in a Thursday, February 19, Instagram video. According to the National Kidney Foundation, stage 3A is mild to moderate kidney function loss. Chronic kidney disease happens when the organs are damaged for more than a few months. The kidneys clean the blood by removing waste and extra fluid.