Could a doc please explain me how the chronic kidney disease secondary to diabetes mellitus works?

Trauma: THe simplest way is to consider the delicate kidney and its filtering system. Now think of a sugar granule all sharp and jagged. At 200 your sugar will pass into the urine the higher your glucose goes the more sugar you pass and the more these sugar granules traumatize the delicate kidney. That's is the easiest way to answer this in 400 letters