You can also find some death records listed in the family records under the individual family name.
This suggestion was posted on the Lewis County Kentucky Genealogy Research Group (you need to be a member of Facebook to access this site).
"For those checking for illnesses/deaths in Vanceburg you might also want to check Scioto County, Ohio and/or Portsmouth Ohio for records. They had the only hospital for miles around and once the Grant Bridge opened in 1927 it was used by Vanceburg, Ky. Google has a good free newspaper site. You can browse the Portsmouth Times for articles and a section called "Around about Portsmouth" lists hospital admitances, sometimes births and releases. So even if your relative lived and died in Lewis County they just might have spent their last days in an Ohio hospital." Connie Coop.
I might add that Manchester, Adams, Ohio is another place to look.