What substances are HIV-infected MSM using that are associated with transmission risk behavior?

Introduction: HIV-infected men-who-have-sex-with-men (MSM) who use substances are more likely to report HIV-transmission-risk-behavior (TRB; any unprotected anal intercourse with HIV-uninfected/unknown status partners within the past 3-months); however, the degree to which specific substances are associated with these behaviors is less understood.

Methods: 503 HIV-infected MSM who received primary care at an urban, northeast health center completed a computer-assisted questionnaire between 2004-2007, which included information on substance use and TRB. Sexually-transmitted-infection (STI) history, CD4-cell count, and HIV-plasma RNA were extracted from patients' electronic medical records. A series of bivariate/multivariable logistic regression procedures were used to examine the associations between TRB and a number of substance-use outcomes.

Results: On average, MSM were 41.9 years old (SD=8.32) and had a CD4 of 530 (SD=385); 75% identified as White, 51.7% had at least a college degree, 6.4% had a history of one or more STIs, and 41.8% had a detectable viral load. MSM reported using marijuana (34%), poppers (27%), crack/cocaine (21%), crystal methamphetamine (20%), GHB (9%), ecstasy (8%), ketamine (7%), opiates (7%), and heroin (1%). Controlling for age, CD4, viral load, education, STI history, and being on HAART, TRB was significantly associated with using the following substances within the past 3-months: marijuana (OR=2.42;p<0.001), poppers (OR=4.08;p<0.001), crack/cocaine (OR=2.04;p=0.003), crystal methamphetamine (OR=5.10;p<0.001), GHB (OR=3.38;p<0.001), ecstasy (OR=4.91;p<0.001), and ketamine (OR=6.48;p<0.001). Conclusions: HIV-infected MSM who engage in TRB are more likely to use myriad substances, which can have deleterious effects on clinical and behavioral outcomes. Interventions with this population should screen and include treatment for substance use problems.