Substance Abuse, HAART Nonadherence, Risky Sex All Linked

Emma Hitt, PhD

August 17, 2011

August 17, 2011 (Atlanta, Georgia) — Amphetamines and injection drug use were most strongly associated with missed dosing and risky sexual behaviors in a large study of HIV-infected patients in primary care, new research suggests.

Matthew J. Mimiaga, ScD, MPH, assistant professor at Harvard Medical School and an investigator at the Fenway Institute, both in Boston, Massachusetts, presented the findings here during a poster session at the 2011 National HIV Prevention Conference (NHPC) here.

"It was necessary to do this study because we know that substance use in general is associated with other risk behaviors, such as unprotected anal sex and poor medication adherence," Dr. Mimiaga told Medscape Medical News. "In addition, it is important to identify the specific drugs that are impeding the ability to take one’s medications as prescribed so that interventions can be targeted effectively," he added.

The researchers analyzed baseline data from 3413 HIV-infected patients engaged in HIV care in 4 cites (Seattle, Washington; Birmingham, Alabama; San Diego, California; and Boston, Massachusetts). All participants completed a "patient-reported outcomes" assessment at baseline. Multivariable logistic regression was used to examine the association of demographic characteristics with sexual behaviors.

Overall, 28% of participants reported using drugs or alcohol before sex, 27% had unprotected anal sex, 25% had unprotected vaginal sex, and 15% missed a dose of medication within the past 7 days.

In addition, within the past 3 months, 3% had used injection drugs, 6% had used opiates, 8% had used crack cocaine, 25% had used amphetamines, and 41% had used marijuana.

The drugs that stood out as being most significant in terms of medication adherence or risky sexual behavior were amphetamines (ie, "crystal meth" and other stimulants) and injection drug use compared with no use of these medications. Amphetamine use within the past 3 months was linked to increased risk of engaging in anal sex (odds ratio [OR], 1.43; P < .001), increased risk for unprotected anal sex (OR, 2.41; P < .001), and increased risk of missing a dose of medication within the past 7 days (OR, 3.23; P < .001).

The risks were even greater for injection drug use. Patients who used injection drugs within the past 3 months were more likely to have anal sex (OR, 1.50; P < .001), to have unprotected anal sex (OR, 8.81; P < .001), and to miss a dose of medication within the past 7 days (OR, 7.92; P < .001).

In comparison, marijuana users had a lesser increased risk for anal sex episodes and missing medication (P < .05 for both) but were not more likely to have unprotected anal sex than nonusers.

The researchers also found that amphetamine and opiate use was more common in the past 3 months in younger than older patients. Black patients were more likely to use crack cocaine than whites. Major depression was strongly associated with marijuana and injection drug use.

"I think this study helps document the high prevalence of substance use in HIV-infected patients seen in the primary care setting and helps document the level of substance abuse, and the importance of being able to triage patients into necessary substance abuse treatment programs is the main clinical relevance," Dr. Mimiaga said.

The study was not commercially funded. Dr. Mimiaga has disclosed no relevant financial relationships.

2011 National HIV Prevention Conference (NHPC): Abstract 006M. Presented August 15, 2011.


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