A Yale professor has rebutted a recent academic study finding that hospitals that treat more low-income patients tend to have higher readmission rates.

Kaiser Health News published a cumulative analysis of 3,119 different hospitals in December 2011, using readmission for congestive heart failure, the most common cause of rehospitilization with 30 days for Medicare patients, as its metric. According to Medicare’s data and the analysis, 11.7 percent of the hospitals that treat the poorest patients had an above-average readmission rate, compared to 4.3 percent for other hospitals.

Citing his own, contrasting study, Harlan Krumholz ’80, a Harold H. Hines Jr. Professor of Medicine at the Yale School of Medicine, does not believe socioeconomic factors are causing hospitals to have higher readmission rates. Krumholz said that while his research supported the idea that hospitals with poorer patients have slightly higher readmission rates, it differed from Kaiser Health’s analysis on the cause of the disparity. He led a study commissioned by the Centers for Medicare and Medicaid Services, a government agency, which found that the cause of higher readmission rates is misguided incentives for hospitals. He is the director of the Center for Outcomes Research and Evaluation, a national research center which focuses on assessing healthcare quality, evaluating decision-making, and comparing effectiveness of different healthcare interventions.

“We need to rethink the way in which we are providing health care, and we have to reassess that convinces us someone is ready to go home,” he said. “We have strong incentives to get people out of the hospital quickly, but we have to start making sure that the patients are ready to leave.”

There is also reason to believe that socioeconomic status has nothing at all to do with hospital readmission rates, Krumholz said. He explained that readmissions rates are roughly identical across the income scale, with patients from “entitled backgrounds” being as likely to end up returning to the hospital as patients from poorer backgrounds.

Krumholz’s study found that the vast majority of hospitals with many poor patients had similar readmission rates as hospitals with fewer such patients did. Because of that, the study concluded that hospitals with a higher share of lower-income patients can perform at least as well on readmission measures, and the problem lay with the medical approach of certain hospitals.

“It’s dangerous thinking, since you’re basically accepting that hospitals that care for those patients of a certain backgrounds are not going to do as well,” Krumholz said.

Krumholz said the best approach is to rethink the entire health care system, and to change the focus of hospitals from doctors’ convenience to patients’ safety.

Thomas Balcezak, vice president of performance management and associate chief of staff at Yale-New Haven Hospital, agrees that hospitals should take on more responsibility for high readmission rates, but does not think it is entirely their fault.

“At our core, hospitals that work in communities have a responsibility to care for patients in those communities, and we have a mission to take care of our community,” Balcezak said. “Whenever you measure things like mortality or readmission, you have to adjust for factors that are beyond the hospital’s or physicians’ control.”

Balcezak said that Yale-New Haven, which has a higher-than-average readmission rate for congestive heart failure, has been trying to decrease the number of patients readmitted by giving discharged patients clearer instructions and advising patients to schedule an appointment with their primary care provider within a week of release.

One of the factors that hospitals cannot control is the resources patients have to live healthy lives, Balcezak said. For example, poor nutrition and health choices made by poorer patients may contribute to the higher-than-average readmission rates.

Gladys Block, a nutrition expert at the University of California who was not involved with the study, attributed the higher readmission rates to poorer health — resulting from unhealthy eating — among people in lower income brackets.

“Sometimes there is low vegetable intake and low micronutrient intake, and as a result of local corner stores charging much more for healthier food options such as fruits and vegetables — cheaper alternatives tend to be unhealthier,” she said.

While Kaiser Health’s analysis did not take racial or ethnic status into account, a study by the Centers for Medicare and Medicaid Services found that many of the hospitals where there is a high volume of African-American patients are also more likely to have high readmission rates.