Decrease in injection and rise in smoking and snorting of heroin and synthetic opioids, 2000–2021

Background

Injecting, smoking, and snorting heroin/synthetic opioids is each associated with unique health risks. It is unclear how route of administration (ROA) preferences have shifted during the opioid epidemic.

Methods

Using 2000–2021 admissions data from SAMHSA TEDS-A, we analyzed trends in heroin/synthetic opioid ROA preferences and factors associated with these preferences.

Results

7,881,318 heroin/synthetic opioid admissions reported injection, smoking, or snorting preference. Nationally, injection peaked in 2014 (69.9 %) and nadired in 2021(52.2 %), snorting nadired in 2014 (24.9 %) and peaked in 2021 (36.4 %), and smoking rose steadily from 2.5 % in 2005 to a peak of 11.4 % in 2021. From 2000–2021, the number of states with ≥10 % smoking rates grew from 2 to 27 (highest: 57.0 % in Arizona in 2021). In 2021, increased adjusted prevalence ratios (APR) of non-injection versus injection use were associated with older age at first opioid use (APR 1.52 [95 % CI: 1.51, 1.54] for those 30+ relative to ≤20), and all race/ethnicities relative to non-Latino White individuals (highest: Black individuals, APR 1.77 [1.75, 1.78]). Geography strongly predicted smoking versus snorting (Mountain APR 6.91 [6.64, 7.19], Pacific APR 6.61 [6.35, 6.88], reference: New England).

Conclusions

ROA preferences of heroin/synthetic opioids have changed substantially since 2000, with: 1) recent decreases in injection nationally; 2) increased smoking, particularly in the western US; and, 3) recent increased snorting in the eastern US. Smoking is now prevalent and growing. Public health implications include an increasing number of smoking-related fatal overdoses and the probable reduction of injection-specific morbidity and increase in smoking-specific morbidity.