Unprotected anal intercourse and substance use before and after HIV diagnosis among recently HIV-infected men who have sex with men.

OBJECTIVE The objective of this study was to assess associations between unprotected anal intercourse (UAI) and substance use before and after HIV diagnosis among recently HIV-infected MSM. STUDY DESIGN Two hundred seven MSM completed computer-assisted self-interviews regarding type and timing of sexual activity and substance use with their last 3 partners. Date of HIV diagnosis was extracted from medical records. Generalized estimating equations, including interaction terms, were used to assess associations between substance use and UAI before and after HIV diagnosis. RESULTS Among partners with whom sexual activity occurred before diagnosis, UAI was associated with methamphetamine use alone (odds ratio = 7.12) and a combination of methamphetamine and other substances (odds ratio = 4.06). However, after HIV diagnosis, UAI was associated with use of substances other than methamphetamine (odds ratio = 3.36), but not methamphetamine alone. CONCLUSIONS Use of illicit substances may be differentially associated with UAI based on knowledge of HIV status and could have implications for prevention of HIV transmission.