Contribution of Opioid-Involved Poisoning to the Change in Life Expectancy in the United States, 2000-2015

Drug poisoning mortality more than doubled in the United States from 2000 to 2015; poisoning mortality involving opioids more than tripled.^1,2 Increases in poisonings have been reported to have reduced life expectancy for non-Hispanic white individuals in the United States from 2000 to 2014.³ Specific contributions of drug, opioid, and alcohol poisonings to changes in US life expectancy since 2000 are unknown.

The number of deaths and death rates in 2000 and 2015 due to poisoning and the 12 leading causes of death in 2015 were estimated using the National Vital Statistics System Mortality file, based on death certificates registered in each state and the District of Columbia. The International Classification of Diseases, Tenth Revision (ICD-10), was used to classify cause of death.⁴ In ranked cause-of-death classification, poisoning is not considered a unique cause. Poisoning deaths are classified as subsets of unintentional injuries, suicides, homicides, or events of undetermined intent.⁴ICD-10 codes for specifically drug, opioid, or alcohol poisoning deaths were defined previously.^1,2,5

Period life tables for the US population in 2000 and 2015 were calculated to estimate life expectancy by age. Life expectancy at any given age is the average number of years of life remaining for those surviving to that age, based on observed period death rates. Changes in life expectancy at birth were partitioned into component parts using the change in the proportion of deaths from specific causes for each age group for 2000 vs 2015.⁴ Stata (StataCorp), version 13, was used to calculate life tables and Excel 2013 (Microsoft) for partitioning. The US Centers for Disease Control and Prevention determined the research was exempt from human subjects regulations because it used existing deidentified data.

Life expectancy at birth increased by 2.0 years overall, rising from 76.8 years in 2000 to 78.8 years in 2015. From 2000 to 2015, death rates related to heart disease, cancer, cerebrovascular diseases, diabetes, influenza and pneumonia, chronic lower respiratory diseases, and kidney disease decreased (Table), together contributing a gain of 2.25 years to the change in life expectancy (Figure). Death rates related to unintentional injuries, Alzheimer disease, suicide, chronic liver disease, and septicemia increased (Table), together contributing a loss of 0.33 years to change in life expectancy (Figure).

Drug-poisoning deaths increased from 17 415 in 2000 to 52 404 in 2015; the age-adjusted death rate per 100 000 population increased from 6.2 to 16.3 (difference, 10.1 [95% CI, 10.1 to 10.2]), with most of the increase (7.4 [95% CI 7.3 to 7.4]) related to opioid deaths (Table). Drug-poisoning deaths contributed a loss of 0.28 years in life expectancy. Most of this loss (96%) was unintentional; 0.21 years were lost to opioid-involved poisoning deaths. Alcohol poisoning contributed a loss of 0.02 years (Figure).

Between 2000 and 2015, life expectancy increased overall but drug-poisoning deaths contributed a loss of 0.28 years. This loss, mostly related to opioids, was similar in magnitude to losses from all the leading causes of death with increasing death rates during this period combined. Nearly all the life expectancy lost due to drug-poisoning deaths was unintentional and was therefore reflected in life lost to unintentional injury. However, unintentional injury appeared to account for less life lost than drug-poisoning deaths because of counterbalancing gains related to decreasing death rates from other unintentional injuries, particularly motor vehicle crashes.³

The finding for the contribution of opioid-involved poisoning deaths to the change in life expectancy is likely an underestimate because the accuracy and completeness of information recorded on death certificates affect cause-specific death rates. A specific drug is not recorded in as many as 25% of drug-poisoning deaths, although this percentage has modestly declined since 2010.

Increases in US life expectancy at birth have leveled off from a mean of 0.20 years gained annually from 1970 to 2000 to 0.15 years gained annually from 2000 to 2014.⁴ US life expectancy decreased from 2014 to 2015 and is now lower than in most high-income countries, with this gap projected to increase.⁶ These findings suggest that preventing opioid-related poisoning deaths will be important to achieving more robust increases in life expectancy once again.

Accepted for Publication: June 23, 2017.

Corresponding Author: Deborah Dowell, MD, MPH, National Center for Injury Prevention and Control, Centers for Disease Control and Prevention, 4770 Buford Hwy NE, MS F-62, Atlanta, GA 30341 (ddowell@cdc.gov).

Author Contributions: Drs Dowell and Arias had full access to all of the data in the study and take responsibility for the integrity of the data and the accuracy of the data analysis.

Concept and design: Dowell, Arias, Guy, Losby.

Acquisition, analysis, or interpretation of data: Dowell, Arias, Kochanek, Anderson, Guy, Baldwin.

Drafting of the manuscript: Dowell, Arias, Baldwin.

Critical revision of the manuscript for important intellectual content: All authors.

Statistical analysis: Arias, Kochanek, Anderson, Guy.

Administrative, technical, or material support: Losby, Baldwin.

Conflict of Interest Disclosures: All authors have completed and submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest and none were reported.

Disclaimer: The views expressed in this article are those of the authors and do not necessarily reflect the official position of the US Centers for Disease Control and Prevention.