nephropathy vs kidney disease

nephropathy and kidney disease both are nouns.

Word	Noun	Adjective	Verb	Adverb
nephropathy	Yes	No	No	No
kidney disease	Yes	No	No	No

As nouns, nephropathy and kidney disease are synonyms defined as:

Other synonyms of nephropathy include nephrosis, renal disorder.

nephropathy (noun)	kidney disease (noun)
a disease affecting the kidneys	a disease affecting the kidneys