Researchers at the University of Illinois at Chicago report that in Illinois hospital visits associated with homelessness have tripled since 2011.

Their findings, which are published in the American Journal of Public Health, also show that beginning in 2016, annual conservative estimates of homelessness using hospital-based data have exceeded similar estimates from the U.S. Department of Housing and Urban Development, or HUD.

“The data suggests that homelessness may be increasing, despite official HUD estimates showing a substantial decrease in homelessness,” said Dana Madigan, a doctoral student at UIC and first author of the study.

Using discharge records from 2011 to 2018, Madigan and her colleagues identified visits to hospital emergency departments in Illinois in which patients indicated they were affected by a lack of housing or homelessness.

Their analysis included more than 200 hospitals, representing 96.5% of all patient admissions statewide in this period.

By matching patient date of birth, gender and race/ethnicity, they estimated the number of unique homeless individuals that visited hospitals in Illinois. They compared their estimates with HUD’s annual estimates of homelessness based on Point-in-Time counts for Illinois, taken on a single night in January.

The most conservative estimates of homelessness using hospital data of unique emergency department visitors increased annually from 6,613 in 2011 to 15,815 in 2018. HUD estimates showed some year-over-year increases, but an overall 24% decrease from 14,009 in 2011 to 10,643 in 2018.

“At the very least, this suggests that state and national estimates of homelessness will be more accurate if they also take into account readily available information from hospitals,” Madigan said.

Lee Friedman, senior author of the study, said that without accurate data, states will not get adequate resources to address homelessness.

“Homelessness is an ‘invisible’ condition that is undoubtedly hard to measure, but that doesn’t mean state and federal agencies get a pass on doing a poor job,” said Friedman, UIC associate professor of environmental and occupational health sciences at the School of Public Health. “HUD’s numbers, which are the primary driver of public policy, may be seriously flawed, and this study shows that hospital data, which is available in every state, is a feasible data system to incorporate into estimates of homelessness to improve accuracy.”

Linda Forst, UIC professor of environmental and occupations health sciences, is a co-author of the study, which was supported in part by the National Institute for Occupational Safety and Health Illinois Education and Research Center (T42OH008672).