Rectal Douching Among Men Who Have Sex with Men in Paris: Implications for HIV/STI Risk Behaviors and Rectal Microbicide Development

Hypo-osmolar rectal douche tenofovir formulation prevents simian/human immunodeficiency virus acquisition in macaques

In spite of the rollout of oral pre-exposure prophylaxis (PrEP), the rate of new HIV infections remains a major health crisis. In the United States, new infections occur predominantly in men having sex with men (MSM) in rural settings where access to PrEP can be limited. As an alternative congruent with MSM sexual behavior, we have optimized and tested tenofovir (TFV) and analog-based iso-osmolar and hypo-osmolar (HOsm) rectal douches for efficacy against rectal simian/human immunodeficiency virus (SHIV) infection of macaques. Single TFV HOsm high-dose douches achieved peak plasma TFV levels similar to daily oral PrEP, while other formulations yielded lower concentrations. Rectal tissue TFV-diphosphate (TFV-DP) concentrations at the portal of virus entry, however, were markedly higher after HOsm douching than daily oral PrEP. Repeated douches led to significantly higher plasma TFV and higher TFV-DP concentrations in rectal tissue at 24 hours compared with single douches, without detectable mucosal or systemic toxicity. Using stringent repeated intrarectal SHIV exposures, single HOsm high-dose douches delivered greater protection from virus acquisition for more than 24 hours compared with oral PrEP. Our results demonstrate a rapid delivery of protective TFV doses to the rectal portal of virus entry as a potential low-cost and safe PrEP alternative.

More than just oral PrEP: exploring interest in rectal douche, dissolvable implant, removable implant and injection HIV prevention approaches among racially diverse men who have sex with men in the Northeast Corridor

OBJECTIVES

HIV scholars and practitioners have worked to expand strategies for prevention among marginalised populations who are disproportionately impacted by the epidemic, such as racial minority men who have sex with men (MSM). Given this urgency, the objective of this study was to assess interest in biomedical prevention strategies.

METHODS

This exploratory and cross-sectional study investigated interest in four biomedical prevention tools-rectal douche, dissolvable implant, removable implant and injection-among a racially diverse sample of MSM from the Northeast Corridor region between Philadelphia and Trenton. Data were collected as part of screening for Connecting Latinos en Pareja, a couples-based HIV prevention intervention for Latino MSM and their partners.

RESULTS

A total of 381 individuals participated in the screener and provided information about their interest in bio tools. Approximately 26% of participants identified as black, 28% as white and 42% as 'other' or multiracial; 49% identified as Latino. Majority (54%) reported some form of child sexual abuse. Of the participants who reported being in a primary relationship (n=217), two-thirds reported unprotected anal sex within that relationship over the past 90 days (n=138, 64%) and approximately half (n=117, 54%) reported unprotected anal sex outside of the relationship in this period. Majority of participants reported interest in all bio tools assessed, including dissolvable implants (60%), removable implants (64%), rectal douching (79%) and injection (79%). Although interest in bio tools was broadly unassociated with demographics and sexual risk behaviours, analyses revealed significant associations between reports of child sexual abuse and interest in implant and injection methods.

CONCLUSIONS

The authors recommend investing in these prevention methods, particularly rectal douching and injection, as a means of preventing HIV among racial minority MSM. Given the interest in biomedical prevention tools, future studies should explore potential strategies for adherence.

Risk factors for HCV transmission in HIV-positive men who have sex with men in México

Purpose

In the last two decades transmission of hepatitis C virus (HCV) in HIV positive men who have sex with men (MSM) has been reported globally. Chemsex and specific sexual practices have been identified as risk factors. Our study aimed to identify risk factors for HCV transmission in MSM living with HIV attending in Mexico.

Methods

We conducted a case-control study from April to December 2019 at the Hospital de Infectología “La Raza” National Medical Center, in Mexico City. A case was defined as an HIV-infected MSM with positive HCV-antibody test. For each case, 3 controls were included, defined as HIV infected MSM with negative HCV-antibody test. A self-questionnaire covering sexual practices and other risk factors for HCV transmission was applied. Bivariate analysis was performed to obtain odds ratio (OR) using Chi-square test. Independent risk factors were identified in a subsequent analysis performing a logistic regression model.

Results

A total of 324 patients participated in the study, 81 cases and 243 controls. Median age was 30.5 years (IQR: 18–52) and 28.8 years (IQR: 21–45) in the case and control group, respectively. Most prevalent HCV genotype was 1a (79%). In the logistic regression model, sharing straw during cocaine inhalation (OR: 9.03; 95% CI; 1.35–13.52; P = 0.003), sharing sex toys (OR: 17.53, 95% CI; 6.85–44.86; P = 0.002), and ethyl chloride use for chemsex (OR: 2.26; 95% CI; 1.29–5.56; P = 0.037) were significant risk factors for HCV infection.

Conclusion

This study identifies risk factors for HCV transmission in Mexico in HIV positive MSM in congruence with the findings of many studies performed worldwide. This is the first study that indicates a possible association between ethyl chloride use in chemsex and HCV infection. Assessment of local populations for risk factors for HCV transmission may help to develop specifically targeted behavioral interventions to reduce HCV transmission.

Getting Clear About Rectal Douching Among Men Who Have Sex With Men

Receptive anal sex is the primary means through which HIV is transmitted among men who have sex with men (MSM). Recently, researchers have begun investigating the role that rectal douching may play in amplifying risk for transmission. Yet, there is limited research on the frequency with which MSM douche, the products they use, and how this may vary across sociodemographic characteristics. A U.S. national sample of 4745 MSM completed an online survey that assessed their douching behavior, demographic characteristics, sexual behavior, and their anal sexual positioning (i.e., top, bottom, versatile). Nearly two-thirds (65.8%) had engaged in rectal douching in the last three months. Among those who douched, water was commonly reported (84.2%) and 20.1% reported using commercial enemas (e.g., Fleet), as well as water and soap (15.0%)-numbers exceed 100% as some participants reported more than one. Men who douched reported significantly more receptive and insertive condomless anal sex acts in the prior 3 months. One-in-ten men reported rectal bleeding after douching. Compared to HIV-negative participants who had not taken PrEP, participants had higher odds of reporting douching in the past 3 months if they were HIV-negative and currently on PrEP (AOR = 1.82), HIV-negative and previously used PrEP (AOR = 1.58), and HIV-positive (AOR = 1.83). Douching was common in this sample. Given that douching could amplify risk for HIV transmission, healthcare providers should discuss douching safety with their patients, with a focus on harm reduction (e.g., reduce risk of bleeding, as opposed to abstinence from douching).

Implementation and Access to Pre-exposure Prophylaxis for Human Immunodeficiency Virus by Men Who Have Sex With Men in Europe

Pre-exposure prophylaxis (PrEP) is a significant public health intervention with proven efficacy and safety in the prevention of human immunodeficiency virus (HIV) infection, which has taken a considerable amount of time to reach Europe in relation to their transatlantic counterparts, namely, the United States of America (USA). There, it is perceived as being an essential prevention tool to be integrated within existing medical, behavioral and structural interventions in place for the management and containment of HIV infection in men who have sex with men (MSM). In a region such as Europe, with approximately double the USA population, it is estimated that not even 10% have proper access to PrEP, and given the lack of coordination with healthcare, taking PrEP has to be at their own expense. Here, we identify the reasons behind the 4-year lag in the approval of PrEP in the European Union/European Economic Area (and Europe in general) and explore the efficacy and effectiveness of PrEP needed to be confirmed with some implementation or demonstration studies conducted in the region. Independent of the data gathered, access of MSM to PrEP is far from ideal in Europe and much still needs to be done. The demonstration of the cost-effectiveness of PrEP alongside other social and behavioral factors needs to be addressed, while the clear populations within MSM that will benefit from this intervention are properly identified and make use of the latest recommendations of the World Health Organization that consider not only daily PrEP but also event-driven PrEP. The momentum for the proper implementation of PrEP in the EU is not lost, and with the existence of generics and even new formulations, there is a renewed opportunity for unleashing the public health benefits arising from this pharmacological tool with other interventions in place (e.g., condoms, testing, and counseling).

Development, Characterization and In Vivo Pharmacokinetic Assessment of Rectal Suppositories Containing Combination Antiretroviral Drugs for HIV Prevention

Receptive anal intercourse (RAI) contributes significantly to HIV acquisition underscoring the need to develop HIV prevention options for populations engaging in RAI practices. We explored the feasibility of formulating rectal suppositories with potent antiviral drugs for on-demand use. A fixed-dose combination of tenofovir (TFV) and elvitegravir (EVG) (40 mg each) was co-formulated in six different suppository bases (three fat- and three water-soluble). Fat-soluble witepsol H15 and water-soluble polyethylene glycol (PEG) based suppositories demonstrated favorable in vitro release and were advanced to assess in vivo pharmacokinetics following rectal administration in macaques. In vivo drug release profiles were similar for both suppository bases. Median concentrations of TFV and EVG detected in rectal fluids at 2 h were 1- and 2-logs higher than the in vitro IC50, respectively; TFV-diphosphate levels in rectal tissues met or exceeded those associated with high efficacy against rectal simian HIV (SHIV) exposure in macaques. Leveraging on these findings, a PEG-based suppository with a lower dose combination of tenofovir alafenamide (TAF) and EVG (8 mg each) was developed and found to achieve similar rectal drug exposures in macaques. This study establishes the utility of rectal suppositories as a promising on-demand strategy for HIV PrEP and supports their clinical development.

Topical delivery of long-acting antiretrovirals to prevent HIV acquisition

PURPOSE OF REVIEW

Although tremendous successes in HIV treatment and prevention have occurred in the past decade, existing HIV prevention options are inadequate, unacceptable or inaccessible to many. Topical antiretroviral-based preexposure prophylaxis (PrEP) options may offer effective, long-acting prevention to those who do not desire systemic exposure to anti-HIV drugs or who want greater control over their own prevention.

RECENT FINDINGS

Among long-acting topical PrEP agents, the dapivirine vaginal ring has advanced the furthest in product development; recent studies have shown high adherence and persistence and evidence of HIV protection in open-label studies as well as a well tolerated safety profile, across the life cycle in women. A range of other long-acting topical PrEP products for vaginal or rectal drug delivery are under development. Rigorous end-user research has explored how to develop products that are behaviorally congruent for the population at risk and has shown that no single product option will be desired by all, but rather different options will achieve the greatest prevention coverage.

SUMMARY

Topically delivered, long-acting antiretroviral PrEP options are being designed to align with user preferences and lifestyles, providing the potential to more effectively expand the HIV prevention method mix and use and achieve an important impact on HIV globally.

Association between rectal douching and HIV acquisition: the mediating role of condom use and rectal bleeding in a national online sample of Chinese men who have sex with men

OBJECTIVES

Previous studies have demonstrated that rectal douching (RD) is associated with HIV acquisition among men who have sex with men (MSM). However, the precise mechanism underlying the association between RD and HIV remains unclear.

METHODS

We recruited participants over WeChat from October 2017 to October 2018. Respondents received mailed HIV self-testing kits, uploaded images of HIV self-test results and completed an online electronic questionnaire simultaneously. The questionnaire assessed sociodemographic characteristics, RD practices and sexual risk behaviours. HIV status was measured as the result of the HIV self-testing. The Baron and Kenny statistical method was used to assess the association between RD and HIV, controlling for condomless anal intercourse (CAI) and rectal bleeding.

RESULTS

Of 1365 participants, 39.93% (545/1365) reported RD in the past 6 months, 60.07% had multiple male sexual partners and 43.08% had CAI in the past 6 months. The prevalence of HIV, based on self-testing, was 3.37% (46/1365). Multivariable logistic analysis showed RD was significantly associated with bottom sexual role (adjusted OR (aOR) 14.0; 95% CI 9.8 to 20.2), having multiple male sexual partners (aOR 1.8; 95% CI 1.4 to 2.2), CAI (aOR 1.3; 95% CI 1.0 to 1.6), rectal bleeding (aOR 2.0; 95% CI 1.6 to 2.6) and HIV infection (aOR 1.9; 95% CI 1.0 to 3.4). Baron and Kenny analysis found both CAI (aOR 2.2; 95% CI 1.2 to 4.1) and rectal bleeding (aOR 1.9; 95% CI 1.0 to 3.4) play a mediating role in the association between RD and HIV.

CONCLUSIONS

Our study results confirmed the relationship between RD and HIV, and found CAI and rectal bleeding mediated HIV infection in Chinese MSM who douched. Strategies should be encouraged to strengthen health education and reduce high-risk sexual behaviour in order to reduce the risk of HIV in MSM who use enemas. Rectal microbicides may represent an efficient means of providing HIV prophylaxis among MSM.

The use of inappropriate anal douching tool associates with increased HIV infection among men who have sex with men: a cross-sectional study in Shenyang, China

Background

Rectal douching (RD) is widely practiced by men who have sex with men (MSM), and is associated with increased risk of HIV infection. However, the mechanism of how RD increases the risk of HIV infection is not well understood, and there is limited data on RD behavior in MSM practicing anal sex in China. We examine the purpose of RD, its timing in relation to anal sex, the types of RD products used, and risky sexual behaviors among MSM reporting anal sex.

Methods

Between August 2017 and December 2018, a cross-sectional study was conducted among adult MSM in Shenyang, China. Data were collected on demographics, sexual behaviors, and RD for the most recent sexual intercourse by means of interviewer-administered face-to-face questionnaires. Blood samples were collected to test for antibodies to HIV and syphilis. Multivariable logistic regression models were used to assess the risk factors associated with HIV infection.

Results

A total of 515 eligible MSM participated in this survey (median age: 31 years). During the most recent anal intercourse, 28.3% (146/515) had condomless receptive anal intercourse (CRAI), 21.4% (110/515) practiced serosorting, and more than half (61.6%, 317/515) reported RD before or after anal sex. Of those practicing RD, 96.8% (307/317) conducted RD before sex, while 62.5% (198/317) conducted RD after sex. The douching devices used were primarily shower hoses (85.3%, 262/307), and relatively few MSM used commercial RD products (8.1%, 25/307) before sex. The prevalence of HIV-1 and syphilis was 11.7% and 13.2%, respectively. HIV infection was positively associated with RD, practicing RD before sex, the interaction between RD and CRAI using a shower hose for RD and other risk factors, practicing RD after sex, CRAI, using nitrite inhalants, main sexual role with males as bottom and syphilis infection.

Conclusions

RD is popular among Chinese MSM. Improper noncommercial RD tools use (such as shower hose), the interaction effect between RD and CRAI associated with HIV infection. Public health workers and the MSM community should publicize scientific knowledge and prevention approaches relating to RD and HIV transmission to MSM. We recommend that further studies should be conducted to understand the detailed mechanism between RD and increased HIV prevalence.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12889-021-10276-z.

Rectal douching among men who have sex with men in six cities in China: a cross-sectional study

Background Rectal douching, which is a common practice among men who have sex men (MSM) as a preparation for anal sex, may potentially increase the risk of HIV infection. However, little is known about the practice of rectal douching among Chinese MSM. This study investigated the characteristics of rectal douching and factors associated with rectal douching.

METHODS

Between January and March 2019, MSM aged ≥18 years in six cities in China were recruited to the study. Participants were asked to complete a self-administered online questionnaire. Chi-squared tests and multivariable logistic regression were used to examine factors associated with rectal douching by calculating odds ratios (ORs) and 95% confidence intervals (CIs).

RESULTS

Of 485 MSM in this study, 278 (57.3%) practiced rectal douching in the preceding 6 months. The most common reasons for douching before and after anal sex were hygiene/cleanliness (78.6% and 66.1% respectively) and HIV/STI prevention (8.5% and 17.4% respectively). The most used enemas and equipment before and after anal sex were tap water (73.5% and 70.2% respectively) and showerhead hoses (76.1% and 75.2% respectively). Men who engaged in both insertive and receptive anal sex (OR 8.84; 95% CI 4.52-17.30), exclusively receptive anal sex (OR 6.56; 95% CI 3.55-12.13), condom-less anal intercourse (OR 1.64; 95% CI 1.03-2.63) and anal sex after alcohol use (OR 1.54; 95% CI 1.00-2.35) were more likely to perform douching.

CONCLUSION

Rectal douching is common in MSM, some of whom may not realise the potential risks associated with douching. The co-occurrence of douching and other high-risk behaviours would make MSM more vulnerable to HIV. Health education aimed at informing MSM of the potential risks and addressing the high prevalence of douching are urgently needed.

Rectal douching in a community sample of men and women

Rectal douching (RD) may be a vector for sexually transmitted infection (STI) acquisition. The aim of this study was to describe the relationship between RD, and the prevalence of various STIs and sexual behaviors in a sample of women and men in Long Beach, California. Five hundred and forty-seven men (mean age 42.8 years) and 530 women (mean age 37 years) recruited from a community-based setting between April 2010 and August 2014 completed the Risk Behavior Assessment and a questionnaire eliciting information on use of lubricants and enemas for vaginal intercourse (VI) and anal intercourse (AI). Participants were screened for high-risk behaviors for human immunodeficiency virus infection including injection drug use. Bivariate analyses were conducted separately for women and men. Based on the empirical results, separate logistic regression models for women and men were constructed. Sensitivity analysis was conducted to assess model fit for reduced samples of only those men and women who reported AI. For men, RD was associated with a lower odds of being hepatitis C antibody positive, greater odds of being positive for hepatitis B virus surface antigen, syphilis, and using lubricants for receptive anal intercourse (RAI). RD in women was associated with higher odds of a positive test for syphilis, ever vaginally douching for VI, and using lubricants for RAI. Men and women who practice RD report positive syphilis test results and use of lubricants for RAI. RD should not be perceived as preventing STIs.

Seeing Is Believing? Unique Capabilities of Internet-Only Studies as a Tool for Implementation Research on HIV Prevention for Men Who Have Sex With Men: A Review of Studies and Methodological Considerations

BACKGROUND

In 2014, Grov et al published a comprehensive review cataloguing both men who have sex with men's (MSM's) sexual behavior transitions in online environments from the 1990s through 2013, as well as researchers' efforts in tandem to use the internet to engage MSM into research, treatment, and prevention.

METHODS

In this article, we discuss historical events and research having occurred in the half decade since the Grov et al publication.

RESULTS

Notable transitions include MSM's expanded use of geosocial networking apps, as well as other forms of social media accessed primarily through mobile devices, as well as the addition of biomedical prevention strategies (eg, pre-exposure prophylaxis and undetectable = untransmittable) to the proverbial HIV prevention toolkit. In tandem, researchers have rapidly expanded their employment of internet-mediated methods for the recruitment and engagement of key populations for HIV research, treatment, and prevention. In this article, we discuss methodological considerations for using the internet to conduct HIV prevention research with MSM: (1) sources of recruitment (eg, geosocial apps, Facebook, crowdsourced online panels); (2) design (eg, cross sectional, longitudinal, diaries); (3) incentives (including disincentivizing fraudulent participants and/or spam bots); (4) confidentiality; and (5) representativeness.

CONCLUSION

We conclude by discussing future directions in HIV prevention research in light of forthcoming technologies such as fifth generation (5G) mobile networks, combined use of self-collected biological data alongside self-report, and the utility of metadata and metaresearch to document, evaluate, and inform best practices.

Use of poppers and HIV risk behaviours among men who have sex with men in Paris, France: an observational study

The use of inhaled nitrites, or poppers, among men who have sex with men (MSM) is prevalent, yet has been associated with HIV seroconversion. We surveyed 580 MSM from a geosocial networking smartphone application in Paris, France, in 2016. Of the respondents, 46.7% reported popper use within the previous 3 months. Regression models adjusted for sociodemographic characteristics found that the use of poppers was significantly (P<0.05) associated with the following during the prior 3 months: condomless anal intercourse (adjusted relative risk (aRR) 1.27, 95% confidence interval (CI) 1.07-1.50), use of alcohol and/or drugs during sex once or twice (adjusted relative risk ratio (aRRR) 2.33, 95% CI 1.44-2.03), three to five times (aRRR 5.41, 95% CI 2.98-9.84) or six or more times (aRRR 4.09, 95% CI 2.22-7.56), participation in group sex (aRRR 3.70, 95% CI 2.33-5.90) and self-reported diagnosis with any sexually transmissible infection over the previous year (aRR 1.63, 95% CI 1.18-2.27), specifically chlamydia (aRR 2.75, 95% CI 1.29-4.29) and syphilis (aRR 2.27, 95% CI 1.29-4.29).

Perceived Candidacy for Pre-exposure Prophylaxis (PrEP) Among Men Who Have Sex with Men in Paris, France

Low perception of HIV risk is a challenge to PrEP implementation. We analyzed associations between perceptions of PrEP candidacy, behavioral indications for PrEP, and sexual behaviors. We recruited a sample of 580 MSM from a geosocial-networking smartphone application in Paris, France. A modified Poisson regression model was conducted to examine associations between perceived candidacy for PrEP and behavioral indications for PrEP, and relationships among engagement in group sex, transactional sex, HIV test history, and indications for PrEP. Adjusted risk ratios (aRR) and 95% confidence intervals (CIs) were calculated. For the outcome of perceived candidacy for PrEP, a multinomial logistic regression was performed, and adjusted relative risk ratios (aRRR) were calculated. Multivariate analyses were adjusted for socio-demographics. Respondents who considered themselves PrEP candidates were more likely to meet PrEP eligibility criteria compared to those who did not consider themselves candidates (aRR 1.65; 95% CI 1.34-2.03). Those who had engaged in group or transactional sex were more likely to have behavioral indications for PrEP (aRR 1.27; 95% CI 1.07-1.50, aRR 1.32; 95% CI 1.13-1.56, respectively), whereas HIV test history was not significantly associated with behavioral indications for PrEP. Respondents who had engaged in group sex or transactional sex were more likely to perceive themselves as candidates for PrEP (aRRR 2.24; 95% CI 1.21-4.16, aRRR 2.58; 95% CI 1.09-6.13, respectively), although those never tested for HIV were less likely to perceive themselves as candidates for PrEP (aRRR 0.18; 95% CI 0.03-0.91). The elucidation of candidacy perceptions and risk behaviors is key to furthering the effective implementation of PrEP engagement interventions.

Recruiting vulnerable populations to participate in HIV prevention research: findings from the Together 5000 cohort study

PURPOSE

The aim of the article was to examine factors associated with completing enrollment milestones in the Together 5000 cohort of at-risk men (n = 8661), transmen (n = 53), and transwomen (n = 63) who have sex with men.

METHODS

Between 2017 and 2018, participants completed an online enrollment survey and were offered opportunities to complete an incentivized secondary online survey as well as self-administered at-home HIV testing (OraSure). We explored factors associated with completing each study component.

RESULTS

In total, 8777 individuals completed our enrollment survey, 6166 (70.3%) completed the secondary survey, and 5010 returned the at-home HIV test kit that was mailed to them (81.3% of those mailed a kit). In our multivariable models, those who were White, with more years of education, were more likely to complete study components, although the magnitude of these associations was small. For example, 50.9% of those enrolled, 47.9% of those completing the secondary survey, and 46.8% of those completing HIV testing were persons of color-a statistically significant, but meaningfully insignificant decline.

CONCLUSIONS

These findings highlight the need for researchers to identify barriers that may prevent persons of color and younger individuals from participating in research studies.

Association between rectal douching and HIV and other sexually transmitted infections among men who have sex with men: a systematic review and meta-analysis

BACKGROUND

Men who have sex with men (MSM) are disproportionately affected by HIV and other STIs worldwide. Rectal douching, which is commonly used by MSM in preparation for anal sex, may increase the risk of HIV and other STIs by injuring the rectal mucosa. Results from individual studies reporting associations between rectal douching and HIV and other STIs among MSM are inconsistent. We performed a systematic review and meta-analysis to estimate the association between rectal douching and HIV and other STIs among MSM.

METHODS

We searched PubMed, Embase, Scopus and Web of Science for studies published from January 1970 to November 2018. Studies that reported ORs and 95% CIs of associations between rectal douching and infection with HIV/STIs, or reported enough data to calculate these estimates, were included. We assessed risk of bias using the Newcastle-Ottawa Scale. ORs were pooled using a random effects model.

RESULTS

Twenty-eight eligible studies were identified in our review, of which 24 (20 398 participants) were included in the meta-analysis. Rectal douching was associated with increased odds of infection with HIV (OR 2.80, 95% CI 2.32 to 3.39), and any STI other than HIV (including hepatitis B virus (HBV), hepatitis C virus (HCV), chlamydia, gonorrhoea, syphilis and human papillomavirus) (OR 2.46, 95% CI 1.95 to 3.11) among MSM. For specific STIs, douching was associated with increased odds of viral hepatitis (HBV, HCV) (OR 3.29, 95% CI 2.79 to 3.87), and chlamydia or gonorrhoea (OR 3.25, 95% CI 2.02 to 5.23). These associations remained significant in studies that adjusted for potential confounders.

CONCLUSION

Rectal douching may put MSM at increased risk for infection with HIV and other STIs. Longitudinal studies are needed to clarify this association, and health education materials should inform men of the potential for increased risk of infection with rectal douching.

Effect of rectal douching/enema on rectal gonorrhoea and chlamydia among a cohort of men who have sex with men on HIV pre-exposure prophylaxis

OBJECTIVES

Rectal douching/enema (RD) is a common practice among men who have sex with men (MSM) in preparation for sex. RD can break down the rectal mucosal barrier and potentially affect the rectal microbiome. The objective of this study was to understand if RD is associated with acquiring rectal infections (RI) with rectal gonorrhoea (NG) and/or chlamydia (CT).

METHODS

From 2013 to 2015, 395 adult HIV-uninfected MSM were enrolled in a randomised controlled study for pre-exposure prophylaxis (PrEP) adherence with routine sexual risk survey and testing. Using data from this cohort, baseline differences by RI were assessed using Pearson's χ² and Wilcoxon-Mann-Whitney test. Association between RD and RI was modelled using multivariable logistic regression adjusted for potential confounders (sexual behaviour, substance use and age) selected a priori. Effect modification by number of male partners and sensitivity analysis to rule out reverse causality were also conducted.

RESULTS

Of 395 participants, 261 (66%) performed RD and 133 (33%) had at least one NG/CT RI over 48 weeks. Number of condomless anal receptive sex (med: 4, p<0.001), male partners (med:6, p<0.001) and substance use (any of methamphetamine/hallucinogens/dissociative/poppers) (p<0.001) were associated with increased odds of RI. Controlling for potential confounders, odds of prevalent RI were 3.59 (p<0.001, 95% CI 1.90 to 6.78) and incident RI 3.87 (p=0.001, 95% CI 1.78 to 8.39) when douching weekly or more compared with not douching. MSM with more than six male partners had 5.34 (p=0.002, 95% CI 1.87 to 15.31) increased odds of RI when douching weekly or more compared with not douching.

CONCLUSION

Rectal hygiene with RD is a common practice (66%) among HIV-uninfected MSM on PrEP in this study, which increases the odds of acquiring rectal NG and/or CT independent of sexual risk behaviour, substance use and other factors. This suggests interventional approaches targeting rectal hygiene products and practices could reduce sexually transmitted infections.