The U.S. opioid-related overdose death rate declined between 2017 and 2018, MedPage Today reports. However, the overdose death rate resulting from synthetic opioids, especially fentanyl, rose during that one-year period. In 2018, synthetic opioids were behind two out of three opioid-related deaths.

Publishing their findings in the Morbidity and Mortality Weekly Report, Centers for Disease Control and Prevention researchers analyzed data from the National Vital Statistics System. They found that there were 67,367 overdose deaths during 2018—a 4.1% decline since 2017—with 46,802 of them related to opioid use.

Between 2017 and 2018, overdose deaths related to prescription opioids declined 13.5%, while deaths tied to heroin declined 4.1% and deaths related to any opioid declined 2%.

During that period, deaths related to synthetic opioids, leaving out those tied to methadone, rose 10%, hitting 31,335 deaths in 2018. That means that about half of all overdose deaths during the latter year were tied to a synthetic opioid.

Fentanyl, the study authors theorized, was likely driving the increase in deaths related to synthetic opioid­s, considering the patterns observed by the Drug Enforcement Agency in their drug seizures.

Death rates related to synthetic opioids increased between 2017 and 2018 in the Northeast, South and West and stayed level in the Midwest.

The overall overdose death rate increased between 2017 and 2018 among Blacks, Latinos and people older than 65.

To read the MedPage Today article, click here.

To read the CDC report, click here.