You have a pleasant 48-year-old man come into your clinic for his annual physical. You have been following him for a number of years and his co-morbidities include HTN, relatively well controlled DM2 with a HbA1c of 7.2, obesity, and tobacco abuse (1ppd and 40 pack year history). He does have a family history of CKD, his brother is 62 and on dialysis and his father died of complications due to ESRD. He takes metformin only and two medications for HTN including HCTZ and metoprolol. Your assessment is benign in terms of physical examination. He has no stigmata of underlying diabetic or hypertensive retinopathy and feels well otherwise. You lab work does uncover a worrisome trend however. Over the course of the last five years his serum creatinine has gradually increased. It was 1.1 in 2014 and today is now 1.5. You are worried that his underlying co-morbities are causing end organ damage in the form of chronic kidney disease and he may have an underlying genetic factor contributing as well.

What are the stages of CKD?