SAUSALITO, CA (ASRN.ORG) -- Large teaching hospitals and hospitals that primarily provide care to poor and uninsured patients are most likely to lose federal money under the U.S. government's plan to improve quality by tying payments to readmissions, according to new research.

"The concern has been raised that when these penalties did come out, they would unfairly target the hospitals that treat the poorest and most complex patients," said Dr. Karen Joynt, the study's lead author from the Harvard School of Public Health in Boston.

As directed by 2010's Affordable Care Act, the Centers for Medicare and Medicaid Services (CMS) - which oversees the federal health insurance programs for the elderly and poor - began tying hospital payments to the number of patients who returned for care within 30 days of their first discharge in October 2012.

If a hospital's readmission rate is higher than CMS's prediction, the agency is allowed to cut the hospital's payments by up to 1 percent of their total Medicare reimbursement. That will increase to 3 percent by 2015.

For 2013, CMS estimates hospitals will lose - on average - 0.3 percent of their funding, about $270 million overall.

The concern, according to Joynt, is that these penalties may have serious implications for poorer hospitals that may not be able to absorb the funding loss.

"Penalizing the ones that can't has the potential to do some real harm," she said.

For the new study, Joynt and her colleague used hospital readmission data from 2008 to 2011 and a survey of about half of the hospitals in the U.S. to compare differences between those that are expected to get the steepest penalties to those that may get the lowest or no penalties.

Overall, 2,189 of the 3,282 hospitals the researchers had data on will be penalized under the new program.

The researchers found that 44 percent of the 270 major teaching hospitals, which typically see patients with more complex medical problems, will see the largest penalties, compared to 33 percent of the 3,012 smaller or non-teaching hospitals.

They also found 44 percent of the 769 safety-net hospitals that mostly serve poor and uninsured patients will get a high penalty, compared to 30 percent of the 2,513 non-safety-net hospitals that serve wealthier and better insured patients.

The researchers write in The Journal of the American Medical Association that they can't say for certain why specific types of hospitals have higher readmission rates when they're compared to others.

But past research suggests higher readmissions may be tied to taking care of poorer patients and patients with more complex medical problems, they write.

QUALITY AND REIMBURSEMENTS

"We want to create incentives but be aware some of these high rates are occurring in resource poor areas," said Dr. Harlan Krumholz, director of the Yale School of Medicine's Center for Outcomes Research and Evaluation in New Haven, Connecticut.

Krumholz, who was not involved with the new study but whose team developed CMS's quality measures, said he'd prefer a system where no hospitals are penalized if they all improve their readmission rates.

Some, including Joynt, have also questioned whether readmission rates are a good measure of a hospital's quality.

Previous research found factors outside of a hospital's control, such as poverty and living situation, may be tied to a person's risk of being readmitted to a hospital.

"I'm not saying we shouldn't be working to improve those things, but I don't think it even passes the reasonability test that a hospital can possibly fill in all those holes," said Joynt.

But Krumholz said it's important to make sure all patients - regardless of social factors - are receiving the same level of care.

"We don't want to have dual standards for patients where we accept poor patients have worse outcomes," he said.