Opioid overdose deaths in US may be underreported by 28%, indicating the crisis is far worse than it appears
The opioid crisis in the US could be far worse than currently estimated. The number of people who have died from opioid overdoses could be 28% higher and have not been added to the already overwhelming toll due to incomplete death records.
This discrepancy is more pronounced in several states, including Alabama, Mississippi, Pennsylvania, Louisiana, and Indiana, where the estimated number of deaths more than doubles, according to researchers from the University of Rochester Medical Center (URMC) Department of Public Health Sciences.
The team found that nearly 72% of unclassified (meaning the drugs involved in the cause of death were not indicated) drug overdoses that occurred between 1999 and 2016 involved prescription opioids, heroin, or fentanyl. This translates into an estimated 99,160 additional opioid-related deaths or approximately 28% more than reported.
Based on their findings, the researchers say the corrected estimates of opioid-related deaths in this study are not trivial and show that the human toll has been substantially higher than reported, by several thousand lives taken each year.
The study was a secondary data analysis of drug overdoses in 1999–2016 obtained from the National Center for Health Statistics Detailed Multiple Cause of Death records. Drug overdoses with known drug classification comprised 78.2% of the cases, and unclassified drug overdoses comprised 21.8%
“In the database of US death records, 21.8% of drug overdoses do not have a classified drug as having caused the overdose. These drug overdoses would be indicated by the exclusive use of ICD-10 code T50.9 — 'Poisoning by, adverse effect of and underdosing of other and unspecified drugs, medicaments and biological substances" — alongside an underlying cause of death indicating a drug overdose. Using our corrected numbers, we found that there were 28% or close to 30% more opioid overdose deaths than previously reported,” senior author of the study Dr Elaine Hill told MEA WorldWide (MEAWW).
“A substantial share of fatal drug overdoses is missing information on specific drug involvement, leading to underreporting of opioid-related death rates and a misrepresentation of the extent of the opioid crisis,” said Dr Hill, an economist and assistant professor in the URMC Department of Public Health Sciences.
According to the Centers for Disease Control and Prevention (CDC), 47,600 people died from opioid overdoses in 2017, but fatal opioid overdoses are probably underreported.
“Undercounting occurs because the drug involved in an overdose is not always specified on death certificates. The drivers of this phenomenon are not fully understood, but are potentially related to inadequate training for coroners without medical experience and variation in substances included in toxicological testing across jurisdictions,” say the researchers in their study published in the journal Addiction.
In addition to the cause of death, the analyzed records also include any additional medical issues that might have contributed to death. Employing a statistical analysis, the researchers were able to correlate the information in the death records of unclassified overdose deaths with contributing causes associated with known opioid-related deaths, such as previous opioid use and chronic pain conditions.
“We separated drug overdoses into two separate bins: drug overdoses with a causal-drug indicated, and drug overdoses without a causal-drug indicated. We then generated a model of opioid involvement in the first set of drug overdoses using contributing causes of death that are not drug-specific (for example, cranial fractures; atrial fibrillation). We then used this model and applied it to the second bin of drug overdoses,” Dr Hill added.
She explains, “By doing so, we obtained probabilities of opioid involvement in this set of drug overdoses. We then calculate the sum of known opioid overdoses and predicted probabilities of opioid involvement for all drug overdoses in the second bin. This provided us with a new estimate of the overall scale of the opioid overdose epidemic.”
While the overall percentage of unclassified deaths declined over time, a phenomenon that the researchers speculate is due to a more focused effort by federal, state, and local officials to understand the scope of the crisis, in several states, the number remained high.
“We found that 71.8% of unclassified drug overdoses in 1999–2016 involved opioids, translating into 99,160 additional opioid-related deaths. Importantly, there was a striking geographic variation in undercounting of opioid overdoses. We found that the absolute increase in opioid overdose rates with this correction is dramatic in certain US states,” says the research team.
According to the analysis, the new estimates show that in Alabama, Mississippi, Pennsylvania, Louisiana, and Indiana, the number of opioid-related deaths increased by more than 100%.
In Pennsylvania, for example, the number of reported opioid-related deaths was 12,374. The study estimates the actual number of deaths was 26,586. Consequently, the state's total number of deaths places it behind only California and Florida, states with significantly higher populations, and moves Pennsylvania from the fifteenth to sixth in terms of highest per capita death rates in 2016, says the team.
The researchers say that the underreporting of opioid-related deaths is very dependent upon location and this new data changes their perception of the intensity of the problem.
"Understanding the true extent and geography of the opioid crisis is a critical factor in the national response to the epidemic and the allocation of federal and state resources to prevent overdoses, treat opioid use disorders, regulate the prescription of opioid medications, and curb the illegal trafficking of drugs," added Dr Hill.