New data show Medicare spent $4.5 billion on new hepatitis C drugs last year—more than 15 times the amount it spent the year before on other treatments for the liver disease, ProPublica reported Sunday. Taxpayers, who are responsible for part of Medicare’s prescription-drug program, largely fund the drugs, which can cost $1,000 a day or more. The spending surge poses a risk of increasing the program’s cost, and also means higher deductibles and maximum out-of-pocket costs for some of Medicare’s 39 million seniors and disabled enrollees, who pay a part of its cost, experts and federal officials say. Sovaldi, which costs $84,000 for a 12-week treatment, accounted for more than $3 billion of the spending. Medicare also spent $157 million on older hepatitis C drugs last year.