Fatal opioid overdoses in the U.S. declined more than reported between 2017 and 2018

Background: In U.S. death records, many drug overdoses do not have classified drug involvement, which challenges surveillance of opioid overdoses across time and space.Objective: To estimate the 2017-2018 change in opioid overdose deaths that accounts for probable opioid involvement in unclassified drug overdose deaths.Methods: In this retrospective design study, data on all drug overdose decedents from 2017-2018 in the U.S. were used to calculate the year-to-year change in known opioid overdoses, predict opioid involvement in unclassified drug overdoses, and estimate the year-to-year change in corrected opioid overdoses, which include both known and predicted opioid deaths. We used the Multiple Cause of Death (MCOD) data from CDC.Results: We estimated that the decrease in the age-adjusted opioid overdose death rate from 2017-2018 was 7.0%. There is a striking variation across states. Age-adjusted opioid overdose death rates decreased by 9.9% in Ohio and more than 5.0% in other Appalachian states (Pennsylvania, West Virginia, Kentucky), while they increased by 6.8% in Delaware.Conclusions: Our models suggest that opioid overdose-related mortality declined from 2017 to 2018 at a higher rate than reported (7.0% versus than the reported 2.0%), potentially indicating that clinical efforts and federal, state, and local government policies designed to control the epidemic have been effective in most states. Our local area estimates can be used by researchers, policy-makers and public health officials to assess effectiveness of state policies and interventions in smaller jurisdictions implemented in response to the crisis.