Thousands of doctors and other medical professionals are billing Medicare for increasingly complicated and costly treatments and this signals a rise in Medicare billing abuse. This is according to an investigation by the Center for Public Integrity which shows that between 2001 and 2010 doctors moved to higher paying codes for billing Medicare for office visits while cutting back on lower paying ones. The organization also found no increase in the average age of patients and the data do not indicate that patients are more infirm as a reason for the increase. This suggests that the shift to higher codes is a result of “upcoding” also known as “code creep” a form of bill padding in which doctors bill Medicare for more expensive services than were actually delivered. Doctors, hospitals and many other providers are paid by medicare based on a series of billing codes. Medicare, covering 49 million elderly Americans spent more than $500 billion in 2011. in a report in May 2012, the Department of Health and Human Services inspector general said that the coding system is vulnerable to fraud and abuse and that it is impossible to determine the precise extent of the problem without looking at the records for each of the 370 million claims Medicare pays annually.