Mortality Data from Opioid, Heroin Overdoses May be Inaccurate

Deaths related to opioids and heroin have been rising in the United States. The impact of the opioid epidemic varies greatly from state to state, as does the proportion of patients dying from opioids versus heroin.

A factor that complicates understanding the full scope of the opioid epidemic is that up to one-quarter of death certificates do not disclose the exact drug responsible. This makes creating targeted enforcement and treatment programs difficult.

The authors of a new study published by the American Journal of Preventive Medicine developed a novel way to refine these data and develop a truer picture of the opioid epidemic. The investigators believe that the novel method can help develop effective approaches against drug misuse.

When using the new method, overall mortality rates were 24% higher for opioids and 22% higher for heroin.

The authors noted that opioid-related mortality rates may be underreported in Pennsylvania, Indiana, New Jersey, and Arizona, while it was overestimated in South Carolina, New Mexico, Ohio, Connecticut, Florida, and Kentucky, according to the study.

Heroin-related death rates were observed to be underestimated in a majority of states, but the authors found that the rates were significantly underestimated in Pennsylvania, Indiana, New Jersey, Louisiana, and Alabama.

"A crucial step to developing policy to combat the fatal drug epidemic is to have a clear understanding of geographic differences in heroin- and opioid-related mortality rates,” said study author Christopher J. Ruhm, PhD. “The information obtained directly from death certificates understates these rates because the drugs involved in the deaths are often not specified."

Data for drug-related deaths of residents were gathered from the CDC’s Multiple Cause of Death (MCOD) files between 2008 and 2014. The MCOD data includes information from death certificates on cause of death, age, race/ethnicity, gender, year, weekday, and place of death.

The death certificate may also list 1 or more drugs involved as immediate or contributory causes of death as codes, including T-codes 40.0-40.4 and 40.6 for opioids and T-code 40.1 for heroin, according to the authors.

Overall, there were 36,450 fatal overdoses in 2008 and 47,055 in 2014. The authors found that unspecified drugs were mentioned in approximately half of cases.

To evaluate corrected rates, information from death certificates where at least 1 specific drug category was identified were used to represent drug involvement when it was unspecified, according to the study. After, the authors applied these corrections to each state’s opioid- or heroin-related death rates.

The investigators found that the corrections drastically changed state mortality rankings, according to the study.

"For instance, Pennsylvania had the 32nd highest reported opioid mortality rate and the 20th highest reported heroin death rate, but ranked seventh and fourth based on corrected rates,” Dr Ruhm said. “Similarly, Indiana's rankings moved from 36th and 29th to 15th and 19th, respectively, and Louisiana's from 40th and 31st to 21st and 20th, respectively. There were 19 states whose corrected and reported opioid rankings differed by at least five places and eight states where this occurred for heroin."

Understanding the inaccuracies caused by a lack of specificity of drug involvement on death certificates is important since federal programs target states that are thought to have a large burden of opioid or heroin use, according to the study. Accurate data could result in better programs for the individuals who need it, the authors noted.

"More fundamentally, geographic disparities in drug poisoning deaths are substantial and a correct assessment of them is almost certainly a prerequisite for designing policies to address the fatal drug epidemic," Dr Ruhm concluded.