Even as researchers have identified a recent plateau in rates of heroin use in the United States, they remain deeply concerned by the existing rate of use, in particular its impact on rising hepatitis C virus (HCV) and HIV rates among people who inject drugs (PWID), Reuters Health reports.

Nora Volkow, MD, director of the National Institute on Drug Abuse, and colleagues conducted a study in which they analyzed data from adult respondents to the 2002 to 2018 National Surveys on Drug Use. These data provided a representative sample of the U.S. population, outside of the incarcerated population. The study authors published their findings in JAMA.

The average age among the 800,500 respondents to the survey was 35 years old. Fifty-three percent were women.

The proportion of the respondents who reported using heroin in the past year increased from 0.17% in 2002 to 0.32% in 2018, for an average annual increase in the rate of 5.6%. More specifically, the heroin use rate only increased between 2002 and 2016, for an average annual increase of 7.6%, and then plateaued through 2018.

The prevalence of reported injection of heroin during the previous year was 0.09% in 2002 and increased to 0.17% in 2018, for an average annual increase of 6.9%. The prevalence of heroin use disorder (addiction to heroin) increased from 0.10% in 2002 to 0.21% in 2018, for an average annual increase of 6.0%. Within this time period, the rate remained stable between 2002 and 2008, increased by an average of 11.3% annually between 2008 and 2015 and then plateaued between 2015 and 2018.

Between 2002 and 2018, the proportion of the survey respondents who reported injecting heroin during the previous year increased continuously among both men and women, those 35 to 49 years old, whites and those living in the Northeast and West.

Among those 18 to 25 years old and those in the Midwest, heroin injection initially increased during the overall study period and then plateaued.

In 2018, the prevalence of reported injection of heroin during the past year was highest among those in the Northeast (0.32% reported such injection), 26- to 34-year-olds (0.31%), 35- to 49-year-olds (0.22%), 18- to 25-year-olds (0.21%), men (0.21%) and whites (0.19%).

Among the 3,200 survey respondents reporting any heroin use, the proportion reporting injecting the drug did not significantly increase during the study period, with 44% reporting doing so during 2002 to 2004 and 49% reporting doing so during 2017 to 2019. Nor did the 2,000 people with heroin use disorder report a significant increase in heroin injection, with 57% reporting doing so during the earlier period and 58% reporting doing so during the latter period.

“The stable prevalence of injection among heroin users and those with heroin use disorder over these years suggests that increases in heroin injection are related to overall increases in heroin use rather than increases in the propensity to inject,” the study authors concluded.

Speaking with Reuters Health, Volkow made a connection between this century’s overall rise in heroin injection and the rise of hep C and HIV cases among PWID. According to the Centers for Disease Control and Prevention, new hep C cases began a sharp increase around 2010, in particular among those in their 20s and 30s. Until recently, national HIV rates among PWID had charted a decline stretching back to around 2000.

“HIV and hepatitis testing and treatment, sterile syringe provision and use of the U.S. Food and Drug Administration–approved medications for opioid use disorder should be expanded, particularly among populations at greatest risk (i.e., adults residing in the Northeast region, adults aged 18 to 49 years, men and non-Hispanic whites),” Volkow and her colleagues concluded in their paper.

To read the Reuters Health article, click here.

To read the study abstract, click here.