By Elise Viebeck - 12/11/12 04:25 PM EST
The instance of kidney failure in the program has more than tripled since the 1980s, the AHA study found.
With obesity, the rates among seniors have more than doubled.
Experts attribute these trends to poorer health among new Medicare beneficiaries and longer U.S. life expectancies, which increase the likelihood patients will develop a chronic illness.
The AHA used the data to challenge Medicare's system for determining hospital payments, known as MS-DRG.
The method's implementation in fiscal 2008 led to lower payment rates that do not reflect the growing burden Medicare patients place on hospitals, the group argued.
"Overall healthcare spending for a person with one chronic condition is almost three times greater than spending for someone without any chronic conditions, and spending is about 17 times greater for someone with five or more chronic conditions," the AHA wrote.
"Policymakers should carefully consider the trends of increasing acuity in the Medicare patient population as they seek changes to payment policy."