Much a-Douche About Nothing? Rectal Douching, HIV, and Sexually Transmitted Infection Risks Among Men Who Have Sex With Men.

Abstract

A recent systematic review and meta-analysis identified a significant association between rectal douching and being diagnosed with HIV (odds ratio [OR], 2.80; 95% confidence interval [CI], 2.32–3.39) or other sexually transmitted infections (STIs; OR, 2.46; 95% CI, 1.95–3.11) among men who have sex with men (MSM).1 Douching is widely practiced in this population,2 which remains at significantly higher risk of HIV and STI acquisition in many settings despite recent advances in prevention technologies. However, the nature of the association, the potential causal mechanisms, and the implications of this finding for research and practice remain uncertain. This uncertainty can be resolved by considering relevant social and behavioral perspectives in study design.3 The review finds that people who report douching are more likely to report positive HIV and STI diagnoses. The hypothesized causal mechanism is physical or biochemical disruption of the anorectal epithelia, which continually produce a thin film of mucus that facilitates fecal transit and mobilizes immune cells. This disruptive effect has been observed in laboratory studies of douching with plain water and with preservative ingredients used in water-based lubricants.4 The resulting inflammation may facilitate HIV and STI acquisition. Cautions should be taken when interpreting the association observed in the review. Douching is an act done in preparation for receptive anal intercourse, which carries greater risk of HIV acquisition than insertive sex (OR, 6.90; 95% CI, 5.50–8.60).5 Thus, significant collinearity between douching and receptive anal intercourse may exist. Although the review included a subanalysis of studies that undertook multivariate regression, it may not be possible to disentangle the effect of potential confounders using data from cross-sectional survey designs. The diversity of sexual cultures and practices among MSM may be masked by survey questions that ask about receptive anal intercourse, particularly when answers are recoded into dichotomous or categorical variables, creating potential for residual confounding. For example, social research identifies sexual practices that are more prevalent among HIV-positive MSM6 and associated with HIV incidence among HIV-negative MSM.7,8 These include condomless anal intercourse with casual partners, group sex, use of sex toys, fisting, and “long play” sessions facilitated by stimulant drugs.9 All of these practices require douching for hygiene and comfort. A question about receptive anal intercourse, not otherwise specified, will fail to distinguish between risks attributable to douching versus sexual practices that require douching. A Dutch study that asked about toys, fisting, rimming, and other practices found no association between douching and current, laboratory-confirmed anorectal STI.10 Douching may therefore be a marker of higher-risk sexual practices,7 requiring more detailed inquiry into sexual practices to clarify its relationship with HIV/STI incidence. Moreover, the low transmission efficiency of HIV means the baseline risk is also low, and that is before a person adopts prevention strategies available to him/her. A person who correctly uses preexposure prophylaxis has almost no risk of infection, whereas a person living with HIV on effective treatment cannot pass the virus on, whether he/she douches or not.11 In populations and settings in which douching continues to predict HIV/STI incidence, sexual health care should make HIV treatment and preexposure prophylaxis widely accessible. Additional research is required to understand the nature of the association and the extent to which it represents a modifiable risk behavior, a marker of particular sexual cultures and practices as well as unmet prevention needs. In crafting educational responses, the experienced practitioner avoids the risk-framed, “just say no” message with its ever-present danger of provoking reactance.12 Nobody likes being told what (not) to do. What matters is identifying what can practicably be done to moderate the risk. To this end, we need to better understand the social practices and sexual contexts in which douching plays a part.