A greater percentage of homeless adults die from drug overdoses than from AIDS, according to a new study. Drug overdoses accounted for nearly 17 percent of all deaths among homeless patients studied, and 81 percent of the overdoses involved opioid painkillers and heroin. In contrast, 6 percent died of causes related to AIDS.

Health issues related to substance abuse, such as alcoholism-associated heart disease, pneumonia and withdrawal, accounted for 8 percent of deaths. The results appear in JAMA Internal Medicine.

Researchers studied 28,033 homeless adults in Boston over five years. The study authors and homeless advocates say their findings apply to homeless populations in many urban areas of the country, Reuters reports.

In a similar study conducted 15 years earlier, 6 percent of deaths among homeless adults were due to drug overdoses, while 18 percent were due to AIDS. “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,” lead researcher Travis Baggett, MD, MPH, of the Massachusetts General Hospital, said in a news release.

Jessie Gaeta, Medical Director of the Boston Health Care for the Homeless Program, told Reuters her group is considering making changes as a result of the findings, including decreasing the amount of painkillers it prescribes, and providing patients with naloxone, which can be used as an overdose antidote.

The program’s doctors prescribe painkillers to some homeless patients with chronic pain, she said. They are increasing efforts to counsel patients on how to properly use their medication, and how to protect against medication theft.