The number of Americans dying of opioid-related overdoses could be more than 20 percent higher than CDC data suggests, according to a study published in the American Journal of Preventative Medicine.
Here are seven things to know.
1. For the study, researchers analyzed data compiled by the CDC on drug overdoses that occurred in the U.S. in 2008 and 2014. According to the data, 36,450 people died of drug overdoses in 2008 and 47,055 died in 2014. When researchers examined documentation of these deaths, they discovered a specific drug was not identified as the cause of death in 19.5 percent of fatal overdoses in 2014 and 25.4 percent in 2008.
2. State-to-state data varied widely with a specific drug mentioned for more than 99 percent of overdose deaths in Rhode Island, Connecticut and New Hampshire for 2014, but only around 50 percent of overdose deaths in Pennsylvania, Indiana, Mississippi, Louisiana and Alabama for the same year.
3. The research team applied a formula based on multiple demographic factors, including race, gender, education level and the location of the death to develop corrected death rates by establishing which overdose deaths without a specific drug listed likely involved opioids.
4. Nationally, corrected opioid overdose mortality rates were 24 percent higher than the CDC reported in 2014. The mortality rate for heroin, specifically, increased by 22 percent.
5. When analyzed at the state-level, the opioid mortality rate changed significantly for some states. "For instance, Pennsylvania had the 32nd highest reported opioid mortality rate and the 20th highest reported heroin mortality rate, but ranked 7th and 4th based on corrected rates," wrote the study's authors.
6. The study authors determined "geographic disparities in drug poisoning deaths are substantial and a correct assessment of them is almost certainly a prerequisite for designing policies to address the fatal drug epidemic."
7. A projection published by the New York Times in June based on CDC data suggested that when the agency finishes tallying drug overdose deaths for 2016, the number will likely fall between 59,000 and 65,000, representing a 19 percent increase from the 52,404 deaths seen in 2015 — a record high.
More articles on opioids:
Physicians from lower-tier med schools prescribe more opioids
Insys Therapeutics may settle Illinois opioid lawsuit for up to $4.5M: 5 things to know
Kentucky imposes 3-day limit on opioid prescriptions: 3 things to know