ID: HR23-669
Presenting author: Courtney McKnight

Presenting author biography:

Dr. Courtney McKnight is a Clinical Assistant Professor in the Department of Epidemiology at the School of Global Public Health at New York University. Dr. McKnight specializes in mixed methods research focused on the epidemiology of drug use, drug overdose, HIV and HCV infection.

Understanding known and unknown fentanyl use: a mixed methods examination of drug overdose risk among people who inject drugs (PWID) during a spike in fatal drug overdose

Courtney McKnight, Allen Weng, Marley Reynoso, Sarah Kimball, Maggie Thompson, Don Des Jarlais
Background:
Deaths due to drug overdose in the United States (US) increased 75% between 2015-2020, largely due to fentanyl, which is being added to heroin often without the knowledge of people who use it. In New York City (NYC), drug overdose deaths increased significantly between 2019-2020, from 21.9 per 100,000 in 2019 to 30.5 per 100,000, with fentanyl involved in 77% of deaths. Using a convergence design, this study examined knowledge of fentanyl use by comparing self-reported (SR) drug use, urine toxicology (UT) results, and data from in-depth interviews with PWID.

Methods
Surveys (N=273) and in-depth interviews (N=155) were conducted in 2021-2022 to investigate drug use, overdose, and experiences with fentanyl. Drug toxicology testing was conducted (N=273) for fentanyl, heroin, other opioids, and stimulants. Using UT results and SR drug use, accuracy of fentanyl exposure was classified into three categories: true-positive (SR+/UT+), false-negative (SR-/UT+) and true-negative (SR-/UT-). Accuracy of fentanyl exposure was compared to several covariates. Thematic analysis was used to identify themes related to experiences with fentanyl and drug overdose.

Results
Urine toxicology results detected 226 (83%) PWID positive for fentanyl and 100 (37%) positive for heroin. The false-negative rate was 81% for fentanyl and 0% for heroin. Fentanyl true-positive PWID were more likely to be young, >1 overdose, higher injection frequency, and use stimulants. False-negative PWID were more likely to use strategies to avoid overdose. Qualitative data indicate that false-negative PWID trusted their drug supplier to inform them of fentanyl in their drugs and had less knowledge about the ubiquity of fentanyl.

Conclusions
Use of fentanyl was common among PWID in this study, but the majority were unaware. A variety of harm reduction strategies are being used to reduce overdose risk, but some may not be effective.