01:09 - Source: CNN
Why are opioids so addictive?

Story highlights

There were an estimated 33,000 opioid-related deaths in the US in 2015, officials say

But new research suggests that even more uncounted deaths may have occurred

CNN —  

Experts say the United States is in the throes of an opioid abuse epidemic, causing 91 overdose deaths each day. Yet the total number of opioid-related deaths may still be underestimated, suggests new research from the US Centers for Disease Control and Prevention.

“In early spring, the Minnesota Department of Health was notified of an unexplained death: a middle-aged man who died suddenly at home,” said Dr. Victoria Hall, a CDC field officer based in Minnesota. He’d been on long-term opioid therapy for back pain, and his family had worried he might be abusing his medication. The medical examiner assigned to the autopsy tested for and diagnosed both pneumonia and a toxic level of opioids.

“However, on the death certificate, it only listed the pneumonia and made no mention of opioids,” Hall said.

The researchers say it may be difficult to track causes of death, such as this one, within surveillance systems that are based solely on autopsy report codes known as International Classification of Diseases, Tenth Edition, or ICD-10.

Over half of the deaths involving opioids in her study had not been captured in the state’s total, said Hall.

“While my research cannot speak to what percent we are underestimating, we know we are missing cases,” Hall said. “It does seem like it is almost an iceberg of an epidemic.”

Hall presented her findings Monday at the annual Epidemic Intelligence Service Conference, which showcased recent CDC investigations. CDC’s “disease detectives’ support over 100 field investigations each year in the US and worldwide.

Rural and urban, men and women

Researchers led by Hall examined death records within the Minnesota Department of Health’s Unexplained Death surveillance system, called UNEX, for 2006 through 2015.

The CDC started the system in 1995 in many states, but Minnesota is the only one to maintain it.

The system was developed to “constantly be on the lookout for emerging diseases,” especially infectious diseases, explained Hall. It identifies cases in which there’s no clear explanation for death so more testing can be performed.

Because research has showed that opioid users are at increased risk of pneumonia, Hall and her colleagues searched for pneumonia as well as other infectious disease deaths among Minnesota residents over the age of 12 to see whether opioids might be involved and found in postmortem toxicology screenings.

Among the 1,676 deaths that fit the researchers’ criteria, 59 (or 3.5%) showed evidence of opioid use. Those 59 deaths had not been picked up by the state’s opioid surveillance system because they lacked the proper ICD-10 code. And, among these 59 deaths, 22 had involved toxic levels of opioids.