The Office of Inspector of the Dept. of Health and Human Services maintains a database of people and organizations excluded from receiving payments from Medicare, Medicaid and other federal health programs. The LEIE–List of Excluded Individuals and Entities–includes individuals excluded for everything from failing to pay off student loans to physically abusing patients to fraud (a complete table of offenses is listed here).
Regardless of which source you believe (always wise to be skeptical about these estimates; see here for a good summary of how hard it can be to pin down their sources), Medicare fraud is a fairly serious problem. The Miami Herald did a great series on the subject in 2008; Poynter’s Al Tompkins wrote up tips for other journalists looking to get into the story, and of course, 60 Minutes did a very good report in October 2009.
The data is available in a Web-based searchable format here, and for download here (unless I’m mistaken, it can only be opened on Windows–I couldn’t open it with my Apple or with the little Linux machine I have at home). a record layout for the data are here.
The site breaks down exclusions by reason here, but Don White, a public affairs spokesman for HHS, tells me those numbers aren’t especially reliable–they’re not based on the latest data. So take these numbers with a grain of salt, but it looks like most of those on the LEIE are there because they lost their license (~20,000), followed by fraud convictions (~13,000 if you add up the two categories) out of ~45,000 exclusions.
I’ve downloaded the most recent data and will look into it more tomorrow.