diabetic coma vs comatoseness

diabetic coma and comatoseness both are nouns.

Word	Noun	Adjective	Verb	Adverb
diabetic coma	Yes	No	No	No
comatoseness	Yes	No	No	No

As nouns, comatoseness is a hypernym of diabetic coma; that is, comatoseness is a word with a broader meaning than diabetic coma:

diabetic coma: coma that can develop in inadequately treated cases of diabetes mellitus
comatoseness: a state of deep and often prolonged unconsciousness; usually the result of disease or injury

Other hypernyms of diabetic coma include coma.

diabetic coma (noun)	comatoseness (noun)
coma that can develop in inadequately treated cases of diabetes mellitus	a state of deep and often prolonged unconsciousness; usually the result of disease or injury