A Research Update from the National Institute on Drug Abuse —
October 2005
Drug abuse is a significant risk factor for HIV/AIDS in the U.S.
- An estimated 1 million people in the U.S. are living
with HIV/AIDS; about one-third of these cases are
linked directly or indirectly to injection drug use.
- In 2003, more than one quarter (11,326) of the
43,171 AIDS cases reported in the U.S. involved
injection drug use.
Some populations are at greater risk.
While anyone can be affected by HIV, some populations are
at increased risk due to a number of complex
biological, social, and economic factors. For example, while
African Americans make up approximately 12
percent of the U.S. population, they accounted for half of
the total AIDS cases diagnosed in 2003. Moreover,
African-American women accounted for 69 percent of female
HIV diagnoses during 2000-2003. In 2001, HIV infection was
the leading cause of death for African-American women,
aged 25-34, African-American men of all ages, and Hispanic
women, aged 35-44. To address these disparities, NIDA is
encouraging research to look at the relationship between
drug abuse and the incidence/prevalence of HIV/AIDS and
AIDS-related morbidity and mortality among these
populations. The goal is to identify effective prevention and
intervention approaches.
Linkages between drug abuse and HIV/AIDS
Early in the epidemic, it became apparent that the HIV virus was being spread, not only through sexual contact
with infected people, but also through the sharing of injection equipment and drug solutions by injection drug users
(IDUs). With such a significant number of HIV cases acquired through injection drug use, effective prevention
interventions were needed. NIDA's research showed that comprehensive HIV prevention--including drug addiction
treatment and community-based outreach, in combination with testing and counseling for HIV and other infections-
-is an effective approach. Such an approach continues to be important in reducing HIV infection risk and
preventing the spread of HIV and other blood-borne infections in drug-abusing populations.
In addition to injection drug use, drug abuse plays other, less recognized, roles in HIV transmission. First, drug
intoxication affects users' mental status and judgment, which, in turn, can increase the likelihood that they will
engage in high-risk sexual behavior. Further, addiction to drugs, as documented for crack cocaine, can further
increase users' exposure to unprotected sex as a means to obtain drugs. Finally, physiological consequences of
drug abuse may alter susceptibility to infection and interact with HIV treatment drugs.
NIDA-supported HIV/AIDS research
In fiscal year 2004, nearly one-third of NIDA's budget was directed to research related to HIV/AIDS and drug
abuse. This significant investment of resources has yielded a number of promising results. For example, recently,
two multi-center research teams, supported in part by NIDA, independently determined through mathematical
modeling that routine HIV-screening of populations with a prevalence rate as low as 1% can provide important
health and survival benefits. The studies also suggest that screening that leads to a diagnosis of HIV infection may
further lower health care costs by preventing high-risk practices and decreasing virus transmission. These studies
demonstrated that HIV screening is as cost effective as screening for conditions, such as breast cancer and high
blood pressure.
Over the years, NIDA's HIV/AIDS research has shown that: (1) addressing co-occurring disorders, such as
Hepatitis C, can improve outcomes; (2) effective HIV-prevention interventions can be tailored to high risk
populations, and (3) drug abuse treatment is a primary means of preventing HIV/AIDS in drug abusers.
Drug abuse, HIV, Hepatitis C
HIV is not the only disease that impacts injection drug users. Another virus, Hepatitis C (HCV), often co-occurs
with HIV in IDUs. Approximately 400,000 individuals in the United States are co-infected with HCV and HIV. As
many as 85-to-90% of HIV-infected IDUs may also be co-infected with HCV. Chronic HCV and HIV co-infection
results in a net increase in the severity of HCV-associated medical consequences, as well as an accelerated
progression to end-stage liver disease and death, as compared to individuals with HCV infection alone. HIV
infection enhances the risk of severe liver disease, especially among drug addicts co-infected with HCV.
Drug abuse prevention effective for specific
populations
NIDA's research has shown that tailoring prevention
intervention programs for specific populations can reduce
HIV risk behaviors. For example, research shows that
school/community-based prevention programs designed
for inner-city African American boys can be effective in
reducing high-risk behaviors, including drug abuse and
risky sexual practices that can lead to HIV infection.
Drug abuse treatment is HIV prevention
NIDA-supported research shows that drug abuse
treatment programs can reduce the risk of HIV
transmission by promoting abstinence from drug use and
reducing HIV-related risk behaviors. For example, the reduction in crack cocaine use after behavioral treatment
was accompanied by a significant drop in HIV risk, mainly as a result of fewer sexual partners and less
unprotected sex. Similarly, numerous studies show that conventional opioid agonist therapy (i.e., methadone
treatment) for IDUs is an effective strategy for decreasing HIV transmission. There is also evidence suggesting
that buprenorphine, a new partial opioid agonist, could curb the spread of HIV.