ALB and Nephropathy: In the classical view of the natural history of DKD, five stages are recognized according to changes in urinary albumin excretion rate and glomerular filtration rate (GFR): hyperfiltration (stage 1), normoalbuminuria or intermittent episodes of microalbuminuria (silent nephropathy, stage 2), persistent microalbuminuria (incipient nephropathy, stage 3), macroalbuminuria and progressive GFR reduction (overt nephropathy, stage 4), and, finally, ESKD (stage 5) [74].