A study by investigators from Massachusetts General Hospital and the Boston Health Care for the Homeless Program compared rates and causes of death with data from a similar 1997 study.
The study found while drug overdose had replaced human immunodeficiency virus as the leading cause of death, overall mortality rates had not changed despite a significant expansion of Boston Health Care for the Homeless Program services.
"Overall, young homeless people died at a nine times higher rate and middle-aged homeless people at a four-and-a-half times higher rate than comparably aged adults in Massachusetts," study leader Dr. Travis Baggett of the Massachusetts General Hospital Department of Medicine, said in a statement.
"Our findings are an unfortunate reminder of the high mortality rate of homeless people and a clarion call for the need to address the epidemic of drug overdose deaths in this vulnerable population."
The study, scheduled to be published in the Feb. 11 issue of Internal Medicine, found drug overdoses accounted for almost 17 percent of all deaths among the homeless patients studied, and 81 percent of those overdoses involved opioid drugs.
Cancer and heart disease -- the primary causes of death among older homeless individuals -- were also significant causes of death among the overall homeless population. Health issues associated with substance abuse, such as alcoholism-associated heart disease, pneumonia and withdrawal, accounted for 8 percent of deaths, the study said.
The investigators analyzed available information for more than 28,000 adult patients who had received care from Boston Health Care for the Homeless Program from 2003 through 2008.
Notable deaths of 2014 [PHOTOS]