A research team recently discovered that there could be many more opioid-related overdose deaths in the United States than what has been believed due to the way deaths have been classified.  Limited information regarding some deaths, upon closer inspection, reveal symptoms of overdose.“Far more people in the U.S. may have died from opioids in the past two decades than previously reported,” according to a new analysis of unclassified drug deaths carried out using machine-learning algorithms led by Elaine Hill and her colleagues at the University of Rochester, New York.The team examined data on drug overdose deaths and found that 22 percent of cases reported between 1999 and 2016 were listed on death certificates as overdoses without specifying the substance.“We found that remarkable, given the scale of the issue,” said Andrew Boslett, one of the researchers.

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As a next step, the researchers began to estimate what percentage of unclassified deaths that were likely due to opioid ingestion, reviewing coroners’ and medical reports from only those specified as opioid-induced and the unclassified overdoses.  Those unclassified were determined to potentially be opioid overdoses by identifying common opioid-related symptoms, such as long-term pain and arthritis.Using this information, the team estimated that “72 percent of unclassified overdose deaths” involved opioids.  The team’s conclusion indicates “99,160 more people in the US have died from opioid overdoses than previously thought, an underestimate of 28 percent.”“We were initially surprised by this data, but then it felt plausible when looking at work that’s been done on a local level,” Hill stated.The researchers are now studying exactly why this happened, and why it could continue to be an issue.“It’s well known in the field that opioid-related overdose deaths are generally undercounted,” Jennifer McNeely at New York University said, adding, “Only by knowing where the epidemic is having the biggest impact can we best target interventions.”“Our lab wants to make as strong of a claim as possible, given evidence that maybe an economic shock had an effect on drug-overdose rates,” Boslett said. “We want to know that the estimates we’re using on local drug-overdose rates are correct, or as correct as possible.”“This paper is a very strong one,” added Atheendar Venkataramani, a health-policy professor at the University of Pennsylvania, who was not involved in the study.  “It suggests if you just follow the vital statistics alone, we’re probably underestimating the true number of opioid deaths…The undercounting of opioid deaths is important because you need to know the scale of a problem to know how to intervene in the problem.”Alina Denham, a doctoral candidate involved in the study, said, “You would think [coroners] would not be able to identify opioid involvement in a death as well as a medical doctor trained in it would.”  However, Hill and her colleagues found coroners were used in the majority of their death investigations.In understanding the symptoms related to accidental opioid overdose, the researchers hope medical examiners will be able to use these commonalities to pinpoint the actual cause of overdose fatalities moving forward.  In the meantime, unfortunately, the numbers will likely still be too low and the practice of not identifying specific substances continues.

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US opioid crisis: 100,000 overdose deaths may have gone uncountedThe Opioid Epidemic Might Be Much Worse Than We Thought