There may be several non-medical factors outside of hospitals' control that are linked to how heart and pneumonia patients fare once they're discharged, according to a fresh look at past research.

Beginning October 1, the Centers for Medicare and Medicaid Services (CMS) started using readmission rates and patient outcomes as a way to determine how much money hospitals should get paid.

But CMS does not consider so-called social factors, such as a patient's living situation or low income, when profiling the quality of a hospital's care.

In the new study, published in the Journal of General Internal Medicine, researchers analyzed data from 72 previous papers examining the reasons people died or were readmitted to the hospital, and found that age, race, employment status, living situation, education and income levels are just some of the factors that may play a role.

"We don't yet know how to accurately measure (the factors), but I think we found enough information to say that they are important and that they should continue to be studied and accounted for," said lead author Dr. Linda Calvillo-King, an assistant professor of internal medicine at the University of Texas Southwestern Medical Center in Dallas.


Calvillo-King said she decided to look this topic when she noticed that patients at her hospital were readmitted because of issues like not being able to take their medication or being unable to get to doctors' offices.

So she and her colleagues gathered research that examined social factors and hospital readmissions in heart and pneumonia patients over about 30 years.

Overall, the researchers were able to pull information from 20 studies looking at pneumonia and 52 looking at heart failure.

For pneumonia patients, among the factors linked to the risk of being readmitted to the hospital were being older and not white. Having a low level of education, low income and being unemployed were also tied to a higher risk of going back into the hospital.

Being older and being a man were each associated with a greater chance of dying within the 30 days after being released from a hospital, as was being a nursing home resident.

For example, in one study from 2002 that was included in the analysis, researchers found that about 17 percent of nursing home residents died after being hospitalized with pneumonia, compared to about 10 percent of other Medicare patients.

For heart failure patients, the risk of being readmitted to a hospital was tied to being elderly, African American or Hispanic.

The type of insurance a person had, their marital status and economic status were also among the factors tied to heart patients' risk of being readmitted to a hospital - as were risky behaviors, such as smoking and cocaine use.

Many of the same factors were linked both to a heart failure patient's risk of death after being hospitalized and the risk of readmission to the hospital.

Some studies also found that living far away from a hospital and feeling cold at home were linked to an increased risk of dying for heart failure patients.


Although Calvillo-King and her colleagues were able to look at a large number of studies, they were all vastly different, she noted.

One study analyzed data for as few as 54 patients, while another looked at more than 8 million.

The studies also included diverse populations and different kinds of social factors, Calvillo-King said.

For example, she told Reuters Health that only some of the studies included details of a patient's social environment, such as their living situation, medications, smoking and substance abuse.

The researchers cannot say for certain that the risk factors identified are what cause a patient to die or to be sent back to the hospital.

But they note in their report that this kind of information could be used by doctors, case managers and discharge planners to flag patients at high risk of readmission because of certain non-medical vulnerabilities, and "Different and more intensive follow-up strategies will likely be necessary in these high social-risk patients...."

Future studies should focus on which factors are the most important, how they should be accounted for and how to address them, Calvillo-King said. "As a physician, these are things that should be taken into account or publicly reported. There is not a lot of research about how that would be done, or what social factors to focus on."

Particularly since CMS compares hospitals "according to 30-day readmission and mortality rates," the researchers write, identifying the social factors that affect patient outcomes and yet are beyond a hospital's control could make assessments of the care patients actually do get in the hospital more accurate.

The Centers for Medicare and Medicaid Services did not provide a statement by press time.