My father has been diagnosed with Stage 3 Chronic Kidney Disease. He has one kidney; the other one was removed in 1998 due to a cancerous tumor. My question is this, how long can someone stay in a Stage 3 status before the kidney possibly worsens to Stage 4? He is on cholesterol medication. He is not a diabetic, and his blood pressure usually runs quite low, i.e., 100/50? He is a non-smoker and eats very well. He drinks lots of water and does not drink alcohol.