Deaths from drug overdose in the United States increased by 54% from 2011 to 2016 — with opioids, benzodiazepines (benzos), and stimulants the most commonly used drug classes involved, a new report released today by the Centers for Disease Control and Prevention's National Center for Health Statistics (NCHS), shows.
The report notes that there were 41,340 drug overdose deaths in 2011 vs 63,632 such deaths in 2016.
Although the opioid oxycodone was the most cited drug in overdose death records in 2011, heroin took the top spot from 2012 to 2015.
The story around fentanyl may be even more troubling. The rate of overdose deaths involving it or one of its analogs doubled each year from 2013 through 2016, when it finally took the lead in becoming the most mentioned drug. In 2016, 29% of all overdose deaths involved fentanyl (n = 18,335).
In addition, cocaine was the second or third most cited drug in the overdose death records throughout the entire study period.
The CDC's list of the 10 most frequently mentioned drugs also included the opioids, methadone, morphine, and hydrocodone; the benzos, alprazolam and diazepam; and the stimulant methamphetamine.
Of all 10 drugs, only methadone was associated with a decreasing overdose death rate from 2011 to 2016.
"While the ranking changed from year to year, the top 10 drugs involved in overdose deaths remained consistent throughout the 6-year period," note the investigators, led by Holly Hedegaard, MD, NCHS.
"This report identifies patterns in the specific drugs most frequently involved in drug overdose deaths…and highlights the importance of complete and accurate reporting in the literal text on death certificates," they write.
The data were published online in the December 12 issue of the National Vital Statistics Reports.
Rise in Overdose Death Toll
An NCHS report released last year showed the age-adjusted rate of US drug overdose deaths increased dramatically from 1999 (6.1 per 100,000 population) to 2016 (19.8 per 100,000).
Although several previous studies on drug overdoses have used National Vital Statistics System-Mortality (NVSS-M) information, this data is coded using the International Classification of Diseases, Tenth Revision (ICD-10); and these ICD-10 codes focus on broad drug categories rather than on individual drugs, note the investigators.
In answer to this, the NCHS and the US Food and Drug Administration "collaboratively developed methods to search the literal text from death certificates to identify mentions of specific drugs and other substances, and to search contextual terms to identify involvement of the drug(s) or substance(s) in the death," the researchers write.
They defined "literal text" as written information from the medical certifier on cause or circumstances related to a death.
For the current report, they examined NVSS-M data from 2011 through 2016. These data were linked to electronic files containing death certificate information.
In addition to the top 10 drugs involved in overdose deaths, drugs that held the number 11 through number 15 ranking throughout the 6-year study period included diphenhydramine, acetaminophen, citalopram, carisoprodol, oxymorphone, tramadol, amitryptyline, clonazepam, gabapentin, and amphetamine.
Threefold Increase in Heroin Deaths
The involvement of heroin in overdose deaths rose threefold from 4571 deaths in 2011 to 15,961 deaths in 2016. This made it the second-most mentioned drug in 2016, behind fentanyl.
Mentions of cocaine increased from 5892 overdose deaths in 2014 to 11,316 deaths in 2016, giving it that year's number 3 ranking.
The fourth most mentioned drug in overdose deaths in 2016 was methamphetamine. Its 6762 related deaths signified a sharp increase from the 1887 related deaths in 2011.
"An analysis of trends…showed that, for several drugs, the age-adjusted rate of drug overdose deaths increased considerably within a relatively short period," the investigators write.
Heroin, cocaine, and methamphetamine all showed significant increasing trends for age-adjusted rates of drug overdose deaths between 2011 and 2016 (1.5 vs 5.1 per 100,000 population; 1.6 vs 3.6 per 100,000; and 0.6 vs 2.1 per 100,000, respectively; all, P < .05).
Fentanyl showed a significant increasing trend between 2013 and 2016 (0.6 vs 5.9 per 100,000; P < .05).
The only decrease for a specific drug came from methadone, which was mentioned in 4545 overdose deaths in 2011 vs 3493 deaths in 2016 (1.4 vs 1.1 per 100,000). Still, it was the eighth most mentioned drug in 2016.
For the 2016 top 10 drugs, "the proportion of deaths involving both the referent drug and at least one other concomitant drug ranged from 50% for methamphetamine to 96% for alprazolam or diazepam," the researchers report.
Finally, drugs most frequently recorded in unintentional overdose deaths in 2016 were fentanyl, heroin, and cocaine. The most frequently cited drugs in suicide by overdose were oxycodone, diphenhydramine, hydrocodone, and alprazolam.
NCHS National Vital Statistics Reports. Published December 12, 2018. Full text