Results from an analysis published in Science showed that mortality rates from drug overdoses in the United States started on a smooth exponential curve at least 15 years prior to the mid-1990s surge in opioid prescribing.
The findings suggest that prevention efforts must address deeper factors driving the epidemic beyond controlling the use of specific drugs.
"The current epidemic of overdose deaths due to prescription opioids, heroin and fentanyl appears to be the most recent manifestation of a more fundamental, longer-term process," Donald S. Burke, MD, dean of the University of Pittsburgh Graduate School of Public Health, said in a press release. "Understanding the forces holding these multiple individual drug epidemics together in a tight upward exponential trajectory will be important in revealing the root causes of the epidemic, and this understanding could be crucial to prevention and intervention strategies."
The researchers examined data on all accidental drug poisoning deaths reported through the U.S. National Vital Statistics System from 1979 to 2016. They assessed overdose mortality rates by individual drug type, including the rates relating to cocaine, heroin and prescription opioids, as well as the underlying demographics of the drug overdose decedents.
When the investigators plotted the annual sum of all drug overdoses over the course of nearly 4 decades, they saw a “remarkably smooth, inexorable exponential curve," lead author Hawre Jalal, MD, PhD, assistant professor of health policy and management at University of Pittsburgh, said in the release. Jalal explained there was no consistent or predictable pattern to the overdose rates for any of the drugs examined in the analysis.
Data showed that mortality rates from drug overdoses in the United States started on a smooth exponential curve at least 15 years prior to the mid-1990s surge in opioid prescribing.
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The investigators found that heroin and cocaine impacted urban populations, while prescription opioids and methamphetamine were more common in rural areas, according to the release. Cocaine-related death rates were higher in black men than other populations, whereas heroin-related mortality was higher in younger whites and older blacks. Overall, as the years progress, mortality rates climb higher for people aged 20 to 65 years, the release stated.
Although cocaine overdose mortality rates fluctuated over the past 20 years, methadone-related deaths have been lessening since the mid-2000s, according to Jalal. Prescription opioids remain on a steady, steep increase. Jalal also noted that methamphetamine deaths appear to be on the rise as well.
Jalal and colleagues performed a geospatial hotspot analysis of overdose deaths by drug. Over the 18-year period, heroin hotspots once clustered around large cities became more widespread, particularly in the Southwest and Northeast, the results showed. Additionally, prescription opioid hotspots have spread to the Western US, Oklahoma, Florida and New England.
“Almost every region in the country is a hotspot for mortality from one or more drugs,” Jalal and colleagues wrote. With the exception, however, of the north central states, which the researchers referred to as a “relative ‘cold spot’ for all drugs.”
"This remarkably smooth, long-term epidemic growth pattern really caught our attention," Burke said in the press release.
However, these findings do not explain how distinctive sub-epidemics of different drugs — including prescription opioids, heroin, methadone, synthetic opioids, cocaine and methamphetamine — have combined into one, tight curve.
"If we can figure it out, we should be able to bend that curve downward. This is a paradox -inexorable growth in the aggregate, composed of variable sub-epidemics. But, it should be solvable,” Burke added. “Evidence-based public health responses have contained past epidemics. If we understand and address these root causes at the same time that we take on the opioid crisis, we should be able to curb the epidemic for good." – by Savannah Demko
: The authors report no relevant financial disclosures.