Jason Salyers, whose health insurer, Anthem, paid for an emergency room visit in 2015 only after he appealed a denial, in Ashland, Ky., May 11, 2018. Anthem denied thousands of claims last year under its “avoidable E.R. program,” which strives to reduce use of a hospital's emergency department, one of the most expensive places to receive medical care. (Luke Sharrett/The New York Times)