Ketones in mammals tend to be similar in types, thus the strips should work OK.
Be aware they only detect 2 if 3 kinds of ketones, so they aren't foolproof.
If your cat has ever had DKA, then getting a blood ketone meter is a good idea. Those will detect ketones in the blood, on average, about 5 days earlier than they will show up in the urine. NovaMax Plus is one brand.