A homeless individual is defined as someone who lacks fixed and reliable housing, and it is estimated that more than half a million people fit that description daily in the U.S. Looking at data across three states, investigators from the Brigham and Beth Israel Deaconess Medical Center (BIDMC) recently found that a growing proportion of homeless patients are being hospitalized and for very different health concerns than the broader American population.

Rishi Wadhera

The retrospective cohort study examined patterns, causes and outcomes of acute hospitalizations for homeless and non-homeless patients in three populous and diverse U.S. states: California, Florida and Massachusetts. They observed a rise in acute hospital use among homeless individuals, primarily driven by mental illness and substance use disorder. The results were published in the journal Medical Care last month.

“The homeless population is aging, and the rate of hospitalizations for homeless individuals is increasing,” said lead author Rishi Wadhera, MD, cardiology fellow in the Division of Cardiovascular Medicine at the Brigham and health policy researcher at BIDMC. “Although there has been a recent push to establish better policy and public health measures to improve the health of homeless adults, few studies have examined the patterns and causes of hospitalizations in this population.”

To examine these trends, hospital discharge data was acquired from Massachusetts and Florida between 2007 and 2013 and from California between 2007 and 2011. This information came from the State Inpatient Databases (SIDs) of the Healthcare Cost and Utilization Project, created by the federal Agency for Healthcare Research and Quality. This dataset includes information such as homeless status, billing, demographics and diagnoses.

Overall, the researchers analyzed over 185,000 hospitalizations for homeless individuals and more than 32 million hospitalizations for non-homeless individuals. Over the periods studied, acute hospitalizations for homeless individuals increased in all three states (see infographic at left). Homeless patients were more often white (62 percent), male (76 percent), around 46 years old and either uninsured (42 percent) or insured by Medicaid (32 percent).

The researchers found that reasons for hospitalization among homeless and non-homeless individuals differed starkly, even after accounting for differences in demographics.

More than 50 percent of hospitalizations among homeless individuals were for mental illness and substance use disorder, while these conditions accounted for less than 20 percent of hospitalizations among demographically comparable non-homeless individuals.

Homeless adults also had a longer mean length of stay, averaging 6.5 days vs. 5.9 days among non-homeless patients. However, homeless individuals had lower in-hospital mortality rates (0.9 percent vs. 1.2 percent) and lower mean costs per day ($1,535 vs. $1,834) than the comparable non-homeless control group.

“Some states, such as Massachusetts, have expanded Medicaid eligibility, which has increased rates of insurance among homeless individuals and improved access to care. This could have led to greater use of hospital services,” said Wadhera.

“The increase in hospitalizations could also reflect more concerning trends. The opioid epidemic has disproportionately impacted the homeless population, and a repercussion of this may be an increase in acute hospitalizations,” he added. “It is also possible that these patterns suggest inadequate longitudinal care for homeless individuals, and that, from a policy perspective, we need to do a better job of providing more consistent, reliable outpatient care to this population.”