NEW YORK — The American opioid crisis has worsened significantly over the past seven years, according to new research by experts at Harvard Medical School, the University of Chicago, and the Ben-Gurion University of the Negev.

Researchers studied 23 million adult hospital admissions at 162 hospitals in 44 states between January 1, 2009 and September 30, 2015. They found that the number of deaths from opioid overdoses have nearly doubled during that span, while healthcare systems around the country are showing signs of strain.

Of the four million total in the study who received acute care, the researchers identified 21,705 people admitted to intensive care units (ICU) because of overdoses from opioids including prescription medications, heroin, and methadone. The average cost of care per admission to the ICU rose from $58,517 at the beginning of the study period to $92,408 in 2015.

“Our findings raise the need for a national approach to developing safe strategies to care for ICU overdose patients, to providing coordinated resources in the hospital for patients and families, and to helping survivors maintain sobriety following discharge,” the authors write.

The study is believed to be the first of its kind to show the impact of widespread opioid abuse on critical care healthcare systems in the U.S. The findings show a fundamental truth: the demand for opioid-related acute care services has grown beyond the supply.

“Estimates may actually be on the low side,” the researchers believe. “Since our team of researchers analyzed admissions rather than a manual chart review, we may not have captured every admission if opioid-related complications weren’t coded as such.”

The full study was published in the Dec. 1, 2017 edition of the Annals of the American Thoracic Society.