The U.S. Senate Permanent Subcommittee on Investigations says its investigation, looking at payouts for 18 different types of medical equipment from 2001 to 2006, uncovered questionable claims totaling more than $1 billion, USA Today reported Wednesday.

Investigators said Medicare paid for walkers for patients whose diagnosis codes indicated sinus congestion, paraplegia or shoulder injuries and diabetes-related blood glucose test strips for patients complaining of breathing problems, bubonic plague, leprosy or impotence, the newspaper said.

"Since when did doctors start prescribing blood-glucose test strips for the bubonic plague?" asked U.S. Sen. Norm Coleman, R-Minn., the committee's ranking Republican. "It seems like a no-brainer that Medicare should check the diagnosis before paying for expensive medical equipment."

"This report highlights a vulnerability that we addressed five years ago," Peter Ashkenaz, spokesman for the Centers for Medicare and Medicaid Services, told USA Today. "CMS has always used clinical information, including diagnosis codes, to target certain vulnerable and high-risk claims. Since 2003, CMS has validated diagnosis codes on all (durable medical equipment) claims."