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Illicit substance use, sexual risk, and HIV-positive gay and bisexual men: differences by serostatus of casual partners

Purcell, David Wa; Moss, Susana; Remien, Robert Hb; Woods, William Jc; Parsons, Jeffrey Td

Original papers

Objective: To examine the use of alcohol and illicit drugs among HIV-positive gay and bisexual men and to determine substance-use-related predictors of unprotected sex with casual partners who were HIV negative, HIV positive, or whose serostatus was unknown.

Design: Cross-sectional assessment of baseline data from a behavioral intervention.

Methods: From 1999 to 2001, we recruited 1168 HIV-positive gay and bisexual men in New York City and San Francisco and determined the prevalence of drinking and drug use, as well as the use of substances with sex. We then examined associations between substance use variables and risky sexual behaviors with casual partners by partner serostatus.

Results: Substance use was common, and the use of ‘party drugs’ [e.g. methamphetamine, nitrate inhalants (poppers), ketamine, and gamma hydroxybutyrate] was most often associated with sexual risk in multivariate models. Substance use before or during sex was not associated with risk with HIV-negative partners, but was associated with risk with HIV-positive and unknown-serostatus partners.

Conclusion: Substance use before or during sex was not associated with risk with HIV-negative partners, suggesting that disclosure by HIV-negative sexual partners of HIV-positive men may be important. Being a user of particular party drugs was associated with recent risk with HIV-negative partners. With partners whose serostatus was unknown, the use of certain party drugs and using substances in the context of sex was associated with risk, possibly as a result of reliance on assumptions of seroconcordance. This same pattern was seen for HIV-positive casual partners. These data have intervention implications for both HIV-positive and HIV-negative men.

From the aCenters for Disease Control and Prevention, Atlanta, GA, USA

bNew York State Psychiatric Institute and Columbia University, New York, NY, USA

cUniversity of California, San Francisco, CA, USA

dHunter College and the Graduate Center of the City University of New York, New York, NY, USA, and the Seropositive Urban Men's Intervention Trial team.

Correspondence to David W. Purcell, JD, PhD, Centers for Disease Control and Prevention, 1600 Clifton Road, MS E-37, Atlanta, GA 30333, USA. Tel: +1 404 639 1934; fax: +1 404 639 1950; e-mail: dpurcell@cdc.gov

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Introduction

Gay and bisexual men represent approximately 58% of men living with AIDS in the United States, and an additional 8% of men who have sex with men (MSM) also use injection drugs [1]. Men of color have been particularly affected by the epidemic, and they represent more than half of new AIDS cases among MSM in the USA every year since 1997 [1,2]. Although gay and bisexual men continue to be concerned about HIV prevention in their communities, recent data in North America, Australia, and Europe suggest a resurgence of unprotected anal sex, sexually transmitted diseases (STD), and HIV infections among these men [3–7]. Although there are many potential explanations for these trends, substance use is one factor frequently found to be associated with sexual risk behavior and the acquisition or transmission of STD or HIV among gay and bisexual men [8–11], including HIV-positive men [12].

Drinking alcohol and using illicit substances are both important to the health of HIV-positive MSM because they can impair immune functioning, react adversely with prescribed medications [13], are related to worse psychosocial and cognitive functioning [14], and potentially decrease adherence to HIV medications [15]. Data from almost 10 000 HIV-positive gay and bisexual men about their alcohol and other substance use during the past 5 years found that approximately 29% of the men had ‘possible’ alcohol abuse, 58% had used a substance other than alcohol, and 9% had injected drugs [16]. Other recent data of substance use in the past 3 months show robust rates of alcohol use (64%), marijuana (36%), nitrate inhalants or ‘poppers’ (27%), cocaine (13%) and amphetamines (12%) among urban, HIV-positive, gay and bisexual men [12]. Qualitative data from HIV-positive gay and bisexual men show that the relationship between substances and sexual risk is complex, and is related to at least three personal factors (behavioral, cognitive, and emotional), and three contextual factors (setting, partner type, and ethnicity) [17].

The potential link between substance use and risky sexual behavior among HIV-positive gay and bisexual men is important to understand so that interventions can be developed to minimize harms to both the infected individual and his partners (such as STD, HIV, and potential re-infection with HIV). Cross-sectional and longitudinal studies have documented an association between drinking or drug use and sexual risk behavior among gay and bisexual men [12,18–25], and longitudinal research shows that men who use certain substances are more likely to become HIV positive [8,26,27]. Studies that look at the link between overall substance use and sexual behavior (without requiring that the two occur at the same time) and studies examining substance use in the context of sexual behavior commonly find an association between substance use and sexual risk, whereas the findings from event-level data have been more mixed [28].

Recent studies have found that the use of specific ‘party drugs’ such as methamphetamine [21,29,30], poppers [12,17,23,31–33], ecstasy [34], and cocaine [35] are likely to be associated with sexual risk, whereas substances such as alcohol or marijuana are often not. Many of the substances associated with unprotected anal intercourse enhance sensations or ease anal penetration (by relaxing sphincter muscles, enhancing stimulation, or lowering inhibitions) [17,30,36,37]. Some of these drugs, particularly methamphetamines, inhibit sexual functioning, and have been associated with viagra use among HIV-positive gay and bisexual men [29]. Substance use also appears to have a greater effect on sexual risk with casual partners compared with primary or main partners [12,38,39].

In this study, we describe the alcohol and non-injection drug use among a diverse group of 1168 HIV-positive gay and bisexual men recruited for an HIV prevention intervention trial. First, we describe the prevalence of drinking alcohol and the use of illicit, non-injection drugs, as well as the prevalence of drinking and the use of illicit substances before or during sex. We include the use of viagra here because men often appear to use it with other party drugs, and we were interested in testing for independent effects on sexual risk. Next, we examined the univariate and multivariate associations between substance use variables and sexual risk. For all analyses, we focused on casual partners and on the sexual behaviors most likely to transmit HIV or STD; unprotected insertive anal intercourse (UIAI) and unprotected receptive anal intercourse (URAI). This study extends the current literature by describing risk practices by partner serostatus separately (HIV-negative partners, unknown-serostatus partners, and HIV-positive partners). This allowed us to examine whether substance use, or substance use in the context of sex, is differentially associated with risk based on the HIV-positive individual's knowledge or perception of the HIV serostatus of his casual partners.

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Methods

Participants

Data reported here are from the baseline quantitative survey gathered using audio-computer assisted self-interviewing technology from a diverse sample of 1168 HIV-positive gay and bisexual men in New York City and San Francisco. Data were collected as part of the Seropositive Urban Men's Intervention Trial, a multi-site randomized controlled trial of an HIV prevention intervention funded by the Centers for Disease Control and Prevention. This study was approved by the Centers for Disease Control and Prevention Institutional Review Board and by the Institutional Review Boards at both sites. The recruitment methods, eligibility, and demographics of the overall sample are described elsewhere in this issue [40].

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Measures

Alcohol use

Men were first asked if they drank any alcohol in the past 90 days. Men who drank alcohol in the past 90 days were then asked about how many times they drank before or during sex during those 90 days.

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Non-injection drug use

Men were first asked if they had used any non injection drugs in the past 90 days. Those who reported non-injection drug use were asked to indicate whether they had used any of the following nine types or classes of drugs: (i) speed/amphetamines; (ii) crystal (methamphetamine); (iii) barbiturates/tranquilizers; (iv) cocaine; (v) ecstasy; (vi) special K (ketamine); (vii) marijuana (pot, hash); (viii) poppers (amyl nitrate); and (ix) GHB (gamma hydroxybutyrate). Correlations between the use of speed/amphetamines and crystal were robust (r = 0.45) but were low enough that we decided to look at the relationships with each category separately. In addition to recording whether the men used each drug or not, we also calculated the number of these illicit, non-injection drugs used in the past 90 days (range from 0 to 9).

Regarding the link between substance use and sexual behavior, we asked the men who used illicit, non-injection drugs about how many times they had used any drugs before or during sex in the past 90 days. This question was a general measure of the use of substances before or during sex and was not specifically linked to specific sexual behaviors or partner serostatus. Finally, because of recent interest in the use of viagra and sexual risk among gay and bisexual men, we asked the men if they were ‘currently taking’ viagra. The use of viagra was not included in the total number of non-injection drugs described above.

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Sociodemographic and health characteristics

Demographic and health variables were used as control variables and were usually collapsed into categories for analyses; city (New York and San Francisco), race/ethnicity (black, Hispanic, white, other), sexual orientation (gay, non-gay), educational background (high school or less, some college or more), personal income (less than US$20 000, US$20 000 or more), and ever been diagnosed with AIDS (yes, no). Age was analysed as a continuous variable.

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Sexual risk behaviors

Sex behaviors of interest (insertive anal and receptive anal sex) were assessed by asking participants to indicate the frequency in the 3 months before baseline of these behaviors, with and without condoms. Separate frequencies were obtained for main partners (defined as ‘a partner you would call your boyfriend, spouse, significant other, or life partner’) and casual partners. For these analyses, frequencies were dichotomized into binary outcomes of ‘never’ or ‘ever in past 3 months’. Sexual risk behavior was analysed in terms of six binary outcomes with casual partners: two risk behaviors; (1) any UIAI, and (2) any URAI, by three serostatuses of casual partners; (1) HIV negative, (2) unknown serostatus, or (3) HIV positive.

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Analytical plan

In preliminary analyses, we determined the prevalence of substance use and substance use in the context of sex. Then we used logistic regression to determine associations between the six outcome variables (sex behavior × partner serostatus) and participant characteristics such as sociodemographics and health status to identify potential control variables needed in analyses of substance use and risk behavior. Sociodemographic and health variables that were significantly associated with a particular outcome (α = 0.05) at the univariate level were used to develop multiple regression models of risk behaviors.

The relationship between substance use and risk behavior was also assessed using logistic regression. We first determined the association between several substance use variables (individual substances, number of substances used, and substance use before or during sex) and each of the six outcomes (sex behavior × partner serostatus) in univariate models. Substance use variables that were significantly associated with a particular outcome (α = 0.05) were then used to develop multiple regression models of the risk behaviors.

Variables for the final six multiple regression models were determined using the automated step-wise selection process in the SAS Logistic Procedure (version 8.2). The main effects for substance use, demographics, and health status were added to the model if they were significant at the α = 0.05 level. After each additional step, effects already in the model were dropped if they did not remain significant (α = 0.05). This step-wise process was used to select an appropriate and parsimonious model given the large number of variables that were significantly associated with the risk behaviors in univariate models and the likely presence of intercorrelations among the substance use variables. Parameters were estimated using maximum likelihood with Fisher scoring.

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Results

Table 1 shows the prevalence of substance use for the overall sample and by city. Three-quarters of the sample drank alcohol in the past 90 days. Almost 60% of the sample had used an illicit drug in the past 90 days, and the most commonly used drugs were marijuana (42%), poppers (26%), cocaine (18%), and methamphetamine (10%). The current use of viagra was 12%, making it one of the more popular substances used by men. HIV-positive men in San Francisco were significantly more likely to have used marijuana, methamphetamine, speed/amphetamines, and GHB, whereas men in New York City were approximately two and a half times more likely to have used cocaine.

Approximately 35% of the sample used two or more illicit drugs and 15% used more than three drugs in the past 3 months. Drinking before or during sex was reported by 57% of men, and illicit non-injection substance use before or during sex was reported by over 47% of men. Men in San Francisco were significantly more likely to report using illicit, non-injection drugs before or during sex than were men in New York City.

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Univariate associations between participant characteristics and sexual risk behavior

We conducted univariate logistic regression models for each of the six outcomes, with participant characteristics including city, race, income, education, sexual orientation, age, and whether the participant had ever been diagnosed with AIDS (data not shown). Significant predictors for each particular outcome were entered into the multiple regression models described below.

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Univariate associations between substance use and sexual risk behavior

Tables 2–4 present crude odds ratios (OR) and 95% confidence intervals (CI) from univariate models of sexual risk by partner serostatus and substance use. We examined the relationships of 11 substance use variables (alcohol, the nine illicit, non-injection drugs, and viagra) with sexual risk. The results indicate that a majority of the substance use variables were significantly associated with sexual risk behaviors with casual partners, regardless of serostatus (Tables 2–4).

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Multiple regression models predicting sexual risk behavior

Tables 5–7 present adjusted OR and 95% CI from multiple regression models of the six outcomes of interest. The final models include only the control (sociodemographic and health) factors and substance use variables that were significantly associated with each risk behavior.

With respect to control variables, health status did not appear to be significantly associated with any risk behavior with casual partners regardless of partner serostatus. However, Tables 5–7 show several general patterns of association between other sociodemographic variables and risk behavior, and where significant, the direction of associations with risk was consistent across specific types of behavior and partner serostatus. Overall, younger participants had greater odds of engaging in risk than older participants. Gay-identified participants had greater odds of engaging in risk than non-gay-identified participants. Higher income participants had greater odds of engaging in risk than lower income participants. More-educated (more than high school) participants had greater odds of engaging in risk than less-educated participants. With respect to race, Hispanic individuals had greater odds of engaging in risk compared with whites, whereas African Americans and participants of other races did not significantly differ from whites.

After controlling for significant sociodemographic variables, the final multiple regression models show several significant associations between substance use and risk behaviors. For HIV-negative casual partners (Table 5), several substance use variables were significantly associated with risk behavior with these partners. In particular, the use of special K (ketamine) was significantly associated with UIAI (OR = 3.1), gamma hydroxybutyrate use was associated with UIAI (OR = 2.2) and URAI (OR = 3.2), and methamphetamine use was associated with URAI (OR = 2.0). Neither drinking nor illicit substance use before or during sex were associated with unprotected sexual behaviors with HIV-negative casual partners.

With casual partners of unknown HIV serostatus, Table 6 shows that several substance use variables were significantly associated with risk behavior with these partners. The use of gamma hydroxybutyrate was significantly associated with UIAI (OR = 5.2), the use of poppers was associated with UIAI (OR = 1.8) and URAI (OR = 1.5), and methamphetamine use was associated with URAI (OR = 2.3). Drinking alcohol before or during sex was associated with UIAI (OR = 1.7) and illicit drug use before or during sex was associated with URAI (OR = 1.8).

With HIV-positive casual partners (Table 7), a number of substance use variables were significantly associated with risk behavior with these partners. The use of gamma hydroxybutyrate was significantly associated with UIAI (OR = 2.4), the use of poppers was associated with URAI (OR = 1.8), and methamphetamine use was associated with UIAI (OR = 2.8) and URAI (OR = 4.3). Drinking alcohol before or during sex was also associated with both unprotected sexual behaviors, and illicit drug use before or during sex was associated with UIAI (OR = 1.6).

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Discussion

HIV-positive gay and bisexual men report significant drinking and substance use as well as drinking and substance use in the context of sex. Drinking and drug use, by themselves, can threaten physical and emotional functioning, as well as the use of medical care and adherence to HIV medications, among HIV-positive individuals [14,41,42]. In addition, the use of certain party drugs, such as methamphetamine, and gamma hydroxybutyrate was associated with sexual risk behaviors with casual partners, regardless of serostatus, even after controlling for the use of other substances. The use of poppers was associated with sexual risk only with HIV-positive or unknown-serostatus casual partners, whereas ketamine was associated with sexual risk only with HIV-negative casual partners. The contextual variables (drinking and drug use before or during sex) were associated with risk behaviors only with HIV-positive and unknown-serostatus casual partners. These findings pose a public health challenge for ensuring the health of HIV-positive gay and bisexual men and their sexual partners.

Recent media and research reports have particularly focused on methamphetamine as a drug that is fueling high-risk sexual behavior and HIV seroconversion among gay and bisexual men [27,30,43,44]. Our data suggest a more complex scenario, with men who report any use of various party drugs reporting more sexual risk behavior, mostly regardless of serostatus. In terms of the method of action, these drugs have some similarities in that they allow individuals to dissociate from reality and to escape the more mundane concerns of life, at least to some extent, and for varying lengths of time [45]. We can thus say that the use of these drugs is a marker of potential risk behavior, but we cannot determine whether these drugs cause risk or whether a third variable is associated with substance use and risk (e.g. individuals who have certain personality characteristics may be drawn to party drugs and risk).

These party drugs are often used in the context of sex and in sexually charged settings, such as dance clubs, circuit parties, sex clubs, and sex parties [46]. Interestingly, in univariate analyses, men who used drugs and drank alcohol before or during sex in the past 3 months were more likely to report engaging in risk behavior in the past 3 months with partners of all serostatuses. However, in multivariate analyses, men who used certain club drugs were more likely to report engaging in risk behavior, but men who reported drinking or using non-injection drugs in the context of sexual behavior did not report more risk with HIV-negative casual partners, only with HIV-positive and serostatus-unknown casual partners. This pattern may suggest the importance of the knowledge of a partner's serostatus among HIV-positive men. Qualitative data looking at sexual risk and substance use among HIV-positive men support this finding at the level of the sexual episode [17]. It may be that, with knowledge of a partner's HIV-negative serostatus, HIV-positive men are more able to enact their plans for safer sex, even if they use substances. The fact that a casual partner says he is ‘negative’, as opposed to not saying anything, and therefore being ‘unknown’ to the participant, may make one or both partners take more responsibility for keeping the HIV-negative partner uninfected. Interventions that attempt to encourage serostatus disclosure by HIV-positive individuals to their sexual partners have been found to reduce risk [47].

For unknown-serostatus partners, drinking before sex was associated with the riskiest sexual behavior (UIAI), and drug use before or during sex was associated with URAI. The pattern of results for unknown-serostatus partners is similar to that reported previously for analyses that combined HIV-negative and unknown-serostatus casual partners into one group [12]. With partners whose serostatus is unknown, substance use in the context of sex is related differently to particular sexual behaviors, suggesting that men may use substances in situations with partners of unknown serostatus to engage in unprotected behaviors, which may be more desirable for some men. For example, many party drugs facilitate receptive anal sex. In a sexual situation in which serostatus is unknown, drug use may allow the positive partner to make assumptions that his partner is also HIV positive, and thus make riskier behavior acceptable. Research shows that in the absence of knowledge, gay and bisexual men make assumptions about their partner's serostatus on the basis of a variety of contextual cues and characteristics [48,49]. Substance use in such a situation may allow men to ignore the fact that they do not know their partner's serostatus, and are actually making a potentially erroneous assumption. Finally, for HIV-positive partners, substance use and contextual variables were also associated with risk. It may be that substances are the social lubricant making risk more likely or facilitating certain sexual behaviors, but the men may have already chosen to accept the risk of unprotected sex with HIV-positive partners, not being as concerned about STI or re-infection as they would be about infecting an HIV-negative man. Substance use may also help HIV-positive men to find and have sex with other HIV-positive partners, which then leads to intentional or accidental unprotected sex.

The overall limitations of the SUMIT study are discussed elsewhere [40], but there are a few additional limitations of these particular analyses. First, the data are cross-sectional, so causation cannot be implied. Therefore, we cannot know whether substance use leads to unprotected sex, whether such sex is planned in advance and substances help it to happen, or whether some third variable such as having a risk-taking personality explain both substance use and transmission risk. In addition, we do not have episode-level data, so we do not know whether substance use during specific sexual episodes was associated with sexual risk behavior among the men or the serostatus of men in any particular sexual episode. Despite these limitations, this study adds to the literature by demonstrating that among HIV-positive MSM: (i) certain party drugs appear to be associated with unprotected sexual behavior with casual partners, regardless of the serostatus of the partner; (ii) focusing on one drug as the cause of problems among any group, such as the current focus on methamphetamine use among gay and bisexual men, is short-sighted and may ignore certain broader dynamics that transcend any particular drug; and (iii) the associations between ‘any substance use in the context of sex’ and ‘any sexual risk behavior in the past 3 months’ vary by the serostatus of the partner.

Substance use among HIV-positive gay and bisexual men is a potential threat to both personal and public health. To understand more about the complex dynamics for gay and bisexual men between HIV status, sexuality, and sexual risk behavior, it would be helpful to conduct additional quantitative and qualitative studies regarding these issues. Focusing on the role of serostatus disclosure by both HIV-positive and HIV-negative men is sorely needed. In addition, qualitative studies about substance use and sexual behavior will allow for a more nuanced understanding of the complex dynamics between sex, substance use, and risk. It is also important for doctors to talk about substance use with their patients, and the challenges that substance use may cause with utilizing medical care, adhering to HIV treatments, and engaging in safer sexual behavior. From a broader perspective, it is also important to understand substance use and sexual behavior in the context of HIV-positive mens’ lives, which may include an abundance of free time (as a result of disability) and potential boredom. Structural solutions that address some of the challenges HIV-positive gay and bisexual men face and tap into some of their altruism may help decrease the link between substance use and risk with HIV-unknown-serostatus partners. By starting to understand these individual and structural dynamics, we can address how some of these intertwined issues contribute to the HIV/AIDS epidemic among gay and bisexual men.

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Acknowledgements

The authors would also like to acknowledge the following people who contributed to this research: Cynthia Gómez, Colleen Hoff, Perry Halkitis, Ann O'Leary, David Bimbi, Rich Wolitski, Tim Matheson, Byron Mason, Carmen Mandic, Bonnie Faigeles, Nick Alvarado, Andrew Nelson Peterson, Eric Rodriguez, Paul Galatowitsch, Michael Marino, Aongus Burke, Michael Stirratt, Eric Martin, Gloria Abitol, Caroline Bailey, and Cindy Lyles.

Sponsorship: Research on SUMIT was funded by the Centers for Disease Control and Prevention through cooperative agreements with New Jersey City University (UR3/CCU216471) and the University of California, San Francisco (UR3/CCU916470).

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Keywords:

drug use; gay and bisexual men; HIV-positive; HIV transmission risk; men who have sex with men; substance use

© 2005 Lippincott Williams & Wilkins, Inc.