HIV transmission risk through anal intercourse: systematic review, meta-analysis and implications for HIV prevention
01 Aug 2010-International Journal of Epidemiology (Oxford University Press)-Vol. 39, Iss: 4, pp 1048-1063
TL;DR: It was demonstrated that it would require unreasonably low numbers of AI HIV exposures per partnership to reconcile the summary per-act and per-partner estimates, suggesting considerable variability in AI infectiousness between and within partnerships over time.
Abstract: Background The human immunodeficiency virus (HIV) infectiousness of anal intercourse (AI) has not been systematically reviewed, despite its role driving HIV epidemics among men who have sex with men (MSM) and its potential contribution to heterosexual spread. We assessed the per-act and per-partner HIV transmission risk from AI exposure for heterosexuals and MSM and its implications for HIV prevention.
Methods Systematic review and meta-analysis of the literature on HIV-1 infectiousness through AI was conducted. PubMed was searched to September 2008. A binomial model explored the individual risk of HIV infection with and without highly active antiretroviral therapy (HAART).
Results A total of 62 643 titles were searched; four publications reporting per-act and 12 reporting per-partner transmission estimates were included. Overall, random effects model summary estimates were 1.4% [95% confidence interval (CI) 0.2–2.5)] and 40.4% (95% CI 6.0–74.9) for per-act and per-partner unprotected receptive AI (URAI), respectively. There was no significant difference between per-act risks of URAI for heterosexuals and MSM. Per-partner unprotected insertive AI (UIAI) and combined URAI–UIAI risk were 21.7% (95% CI 0.2–43.3) and 39.9% (95% CI 22.5–57.4), respectively, with no available per-act estimates. Per-partner combined URAI–UIAI summary estimates, which adjusted for additional exposures other than AI with a ‘main’ partner [7.9% (95% CI 1.2–14.5)], were lower than crude (unadjusted) estimates [48.1% (95% CI 35.3–60.8)]. Our modelling demonstrated that it would require unreasonably low numbers of AI HIV exposures per partnership to reconcile the summary per-act and per-partner estimates, suggesting considerable variability in AI infectiousness between and within partnerships over time. AI may substantially increase HIV transmission risk even if the infected partner is receiving HAART; however, predictions are highly sensitive to infectiousness assumptions based on viral load.
Conclusions Unprotected AI is a high-risk practice for HIV transmission, probably with substantial variation in infectiousness. The significant heterogeneity between infectiousness estimates means that pooled AI HIV transmission probabilities should be used with caution. Recent reported rises in AI among heterosexuals suggest a greater understanding of the role AI plays in heterosexual sex lives may be increasingly important for HIV prevention.
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TL;DR: The results of this study show that many of the top-selling brands of water-based sexual lubricants available in SA are hyperosmolar, which may have the potential to increase HIV acquisition and transmission, if they are used during UAI.
Abstract: Background . Men who have sex with men (MSM) are at high risk for HIV acquisition and transmission. There is a high HIV-transmission potential associated with unprotected anal intercourse (UAI), which requires sexual lubrication for comfortable, non-traumatic anal sex. Lubricant distribution remains poor in many developing nations and MSM have been known to substitute a number of common household or food products to ensure comfortable anal sex. Concern has been raised about the potential toxicity of lubricants used during anal sex. Epithelial injury is related to the osmolality of the lubricant product. Objective . To analyse commercially available water-based sexual lubricant products to ascertain their osmolality and potential to cause rectal epithelial damage. Methods. The osmolality and glycerol concentration was determined for eight of the most frequently purchased water-based sexual lubricants and some commonly used household/food products. Results . Osmolality ranged from 270 - 9 440 mosmol/l (Lubrimaxxx Premium, containing phytosqualane, and JO H 2 O Water Based Lubricant, respectively). Seven (88%) of the commercial lubricants had high osmolalities, with two products approaching 10 000 mosmol/l, far in excess of serum which has an osmolality of ~280 mosmol/l. Conclusion . The results of this study show that many of the top-selling brands of water-based sexual lubricants available in SA are hyperosmolar. Given that hyperosmolar products have been shown in vitro and in vivo to cause epithelial injury, they may have the potential to increase HIV acquisition and transmission, if they are used during UAI. Awareness needs to be raised about the mucosal safety of lubricants designed for use during anal sex.
21 citations
Cites background from "HIV transmission risk through anal ..."
...Receptive UAI is approximately 16 times more likely to result in HIV transmission than unprotected vaginal intercourse due to the fact that the anal mucosa is thinner than vaginal mucosa and does not self-lubricate before or during intercourse.([2]) The HIV transmission risk associated with UAI applies equally to women engaging in this sexual behaviour....
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TL;DR: Results indicate that GBM sex-drug use behavior features rational decision-making strategies linked to anal sex roles, and that sexual behavior research can benefit from partnership analysis.
Abstract: This study analyzed event-level partnership data from a computer-assisted survey of 719 gay and bisexual men (GBM) enrolled in the Momentum Health Study to delineate potential linkages between anal sex roles and the so-called "sex drugs," i.e., erectile dysfunction drugs (EDD), poppers, and crystal methamphetamine. Univariable and multivariable analyses using generalized linear mixed models with logit link function with sexual encounters (n = 2514) as the unit of analysis tested four hypotheses: (1) EDD are significantly associated with insertive anal sex roles, (2) poppers are significantly associated with receptive anal sex, (3) both poppers and EDD are significantly associated with anal sexual versatility, and (4) crystal methamphetamine is significantly associated with all anal sex roles. Data for survey respondents and their sexual partners allowed testing these hypotheses for both anal sex partners in the same encounter. Multivariable results supported the first three hypotheses. Crystal methamphetamine was significantly associated with all anal sex roles in the univariable models, but not significant in any multivariable ones. Other multivariable significant variables included attending group sex events, venue where first met, and self-described sexual orientation. Results indicate that GBM sex-drug use behavior features rational decision-making strategies linked to anal sex roles. They also suggest that more research on anal sex roles, particularly versatility, is needed, and that sexual behavior research can benefit from partnership analysis.
21 citations
TL;DR: The authors concluded that the rate of AI was relatively low among heterosexuals and that, “even among those who do engage in AI, most do so at significantly lower rates than VI”, and suggested that AI is unlikely to account for a large fraction of new HIV infections in Africa, but its role should not be underestimated given its higher transmission efficiency.
Abstract: In this issue (see page 411) , Kalichman et al 1 report the results of a cross-sectional study on anal intercourse (AI) of heterosexual men and women in South Africa (SA).1 This study is a welcome addition to the literature, since there are relatively few studies quantifying rates of AI among heterosexual populations, especially in SA. Overall, 14% men and 10% women reported AI in the previous 3 months. Among those, 56% did in at least 50% of all sex acts and reported using condoms as often for AI as for vaginal intercourse (VI). Despite this, the authors concluded that the rate of AI was relatively low among heterosexuals and that, “even among those who do engage in AI, most do so at significantly lower rates than VI” (total VI = 9.90, total AI = 8.47) based on reported mean frequencies of all (protected and unprotected) VI and AI (table 3)*. However, we believe that the observed differences in unprotected VI and AI are not sufficient to assert this with confidence, especially for men (mean frequency of unprotected AI and VI acts: 3.61 and 4.56 respectively for females, 3.11 and 3.04 for males). They further argued that, although the role of AI remains unclear, the HIV epidemic in SA cannot be primarily attributed to AI and that AI “should neither be the focus of nor ignored by HIV prevention interventions in SA.” They also suggest that, relative to VI, AI is unlikely to account for a large fraction of new HIV infections in Africa, but its role should not be underestimated given its higher transmission efficiency.
As stated by the authors, an important limitation of these results is that the AI rate may be underestimated, given the sensitivity of subject matter and the interviewing method used (self-administered questionnaire with minimal assistance). Studies …
21 citations
TL;DR: Habitual condom use among younger men who have sex with men (YMSM), aged 16–29, surveyed in New Zealand, highlights the value of early, engaging and sustained condom promotion.
Abstract: Objectives Our objectives were to investigate demographic and behavioural factors associated with condom use and to examine how habitual condom use was across partner types and sexual positions among younger men who have sex with men (YMSM), aged 16–29, surveyed in New Zealand. Methods We analysed the 2006–2011 national HIV behavioural surveillance data from YMSM who reported anal intercourse in four scenarios of partner type and sexual position: casual insertive, casual receptive, regular insertive and regular receptive. For each, respondents’ condom use was classified as frequent (always/almost always) or otherwise, with associated factors identified with multivariate mixed-effect logistic regression. Habitual condom use across scenarios was examined using a latent variable technique that estimated the intraclass correlation coefficient (ICC). Results Frequent condom use was reported for 63.6% of 5153 scenarios reported from 2412 YMSM. Frequent use increased from boyfriend to fuckbuddy to casual partners. Infrequent use was associated with online recruitment, Pacific ethnicity, less education, HIV positivity, sex with women, having ≥20 sexual partners versus 1 and reporting insertive and receptive sexual positions. Frequent condom use was associated with having two to five sexual partners versus one and shorter regular partnerships. The ICC=0.865 indicated highly habitual patterns of use; habitual infrequent condom use was most prevalent with regular partners (53.3%) and habitual frequent condom use was most prevalent with casual partners (70.2%) and for either sexual position (50.5% and 49.1%). Conclusions Habitual condom use among YMSM highlights the value of early, engaging and sustained condom promotion. Public health should provide better and more compelling condom education, training and promotion for YMSM.
21 citations
DOI•
01 Jan 2015
TL;DR: In this article, the authors present a Table of Table of contents of the paper "A.K.A., Table of Contents" and Table of Content: https://www.goup.com/
Abstract: ......................................................................................................................................... ii Preface ........................................................................................................................................... iii Table of
21 citations
Cites background from "HIV transmission risk through anal ..."
..., 2009), a risk that extends equally to both males and females alike (Baggaley et al., 2010; Beyrer et al., 2012; Boily et al., 2009)....
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References
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TL;DR: A new quantity is developed, I 2, which the authors believe gives a better measure of the consistency between trials in a meta-analysis, which is susceptible to the number of trials included in the meta- analysis.
Abstract: Cochrane Reviews have recently started including the quantity I 2 to help readers assess the consistency of the results of studies in meta-analyses. What does this new quantity mean, and why is assessment of heterogeneity so important to clinical practice?
Systematic reviews and meta-analyses can provide convincing and reliable evidence relevant to many aspects of medicine and health care.1 Their value is especially clear when the results of the studies they include show clinically important effects of similar magnitude. However, the conclusions are less clear when the included studies have differing results. In an attempt to establish whether studies are consistent, reports of meta-analyses commonly present a statistical test of heterogeneity. The test seeks to determine whether there are genuine differences underlying the results of the studies (heterogeneity), or whether the variation in findings is compatible with chance alone (homogeneity). However, the test is susceptible to the number of trials included in the meta-analysis. We have developed a new quantity, I 2, which we believe gives a better measure of the consistency between trials in a meta-analysis.
Assessment of the consistency of effects across studies is an essential part of meta-analysis. Unless we know how consistent the results of studies are, we cannot determine the generalisability of the findings of the meta-analysis. Indeed, several hierarchical systems for grading evidence state that the results of studies must be consistent or homogeneous to obtain the highest grading.2–4
Tests for heterogeneity are commonly used to decide on methods for combining studies and for concluding consistency or inconsistency of findings.5 6 But what does the test achieve in practice, and how should the resulting P values be interpreted?
A test for heterogeneity examines the null hypothesis that all studies are evaluating the same effect. The usual test statistic …
45,105 citations
TL;DR: A checklist contains specifications for reporting of meta-analyses of observational studies in epidemiology, including background, search strategy, methods, results, discussion, and conclusion should improve the usefulness ofMeta-an analyses for authors, reviewers, editors, readers, and decision makers.
Abstract: ObjectiveBecause of the pressure for timely, informed decisions in public health
and clinical practice and the explosion of information in the scientific literature,
research results must be synthesized. Meta-analyses are increasingly used
to address this problem, and they often evaluate observational studies. A
workshop was held in Atlanta, Ga, in April 1997, to examine the reporting
of meta-analyses of observational studies and to make recommendations to aid
authors, reviewers, editors, and readers.ParticipantsTwenty-seven participants were selected by a steering committee, based
on expertise in clinical practice, trials, statistics, epidemiology, social
sciences, and biomedical editing. Deliberations of the workshop were open
to other interested scientists. Funding for this activity was provided by
the Centers for Disease Control and Prevention.EvidenceWe conducted a systematic review of the published literature on the
conduct and reporting of meta-analyses in observational studies using MEDLINE,
Educational Research Information Center (ERIC), PsycLIT, and the Current Index
to Statistics. We also examined reference lists of the 32 studies retrieved
and contacted experts in the field. Participants were assigned to small-group
discussions on the subjects of bias, searching and abstracting, heterogeneity,
study categorization, and statistical methods.Consensus ProcessFrom the material presented at the workshop, the authors developed a
checklist summarizing recommendations for reporting meta-analyses of observational
studies. The checklist and supporting evidence were circulated to all conference
attendees and additional experts. All suggestions for revisions were addressed.ConclusionsThe proposed checklist contains specifications for reporting of meta-analyses
of observational studies in epidemiology, including background, search strategy,
methods, results, discussion, and conclusion. Use of the checklist should
improve the usefulness of meta-analyses for authors, reviewers, editors, readers,
and decision makers. An evaluation plan is suggested and research areas are
explored.
17,663 citations
TL;DR: The problem of making a combined estimate has been discussed previously by Cochran and Yates and Cochran (1937) for agricultural experiments, and by Bliss (1952) for bioassays in different laboratories as discussed by the authors.
Abstract: When we are trying to make the best estimate of some quantity A that is available from the research conducted to date, the problem of combining results from different experiments is encountered. The problem is often troublesome, particularly if the individual estimates were made by different workers using different procedures. This paper discusses one of the simpler aspects of the problem, in which there is sufficient uniformity of experimental methods so that the ith experiment provides an estimate xi of u, and an estimate si of the standard error of xi . The experiments may be, for example, determinations of a physical or astronomical constant by different scientists, or bioassays carried out in different laboratories, or agricultural field experiments laid out in different parts of a region. The quantity xi may be a simple mean of the observations, as in a physical determination, or the difference between the means of two treatments, as in a comparative experiment, or a median lethal dose, or a regression coefficient. The problem of making a combined estimate has been discussed previously by Cochran (1937) and Yates and Cochran (1938) for agricultural experiments, and by Bliss (1952) for bioassays in different laboratories. The last two papers give recommendations for the practical worker. My purposes in treating the subject again are to discuss it in more general terms, to take account of some recent theoretical research, and, I hope, to bring the practical recommendations to the attention of some biologists who are not acquainted with the previous papers. The basic issue with which this paper deals is as follows. The simplest method of combining estimates made in a number of different experiments is to take the arithmetic mean of the estimates. If, however, the experiments vary in size, or appear to be of different precision, the investigator may wonder whether some kind of weighted meani would be more precise. This paper gives recommendations about the kinds of weighted mean that are appropriate, the situations in which they
4,335 citations
TL;DR: The viral load is the chief predictor of the risk of heterosexual transmission of HIV-1, and transmission is rare among persons with levels of less than 1500 copies of HIV -1 RNA per milliliter.
Abstract: Background and Methods We examined the influence of viral load in relation to other risk factors for the heterosexual transmission of human immunodeficiency virus type 1 (HIV-1). In a community-based study of 15,127 persons in a rural district of Uganda, we identified 415 couples in which one partner was HIV-1–positive and one was initially HIV-1–negative and followed them prospectively for up to 30 months. The incidence of HIV-1 infection per 100 person-years among the initially seronegative partners was examined in relation to behavioral and biologic variables. Results The male partner was HIV-1–positive in 228 couples, and the female partner was HIV-1–positive in 187 couples. Ninety of the 415 initially HIV-1–negative partners seroconverted (incidence, 11.8 per 100 person-years). The rate of male-to-female transmission was not significantly different from the rate of female-to-male transmission (12.0 per 100 person-years vs. 11.6 per 100 person-years). The incidence of seroconversion was highest among ...
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TL;DR: A theoretical strategy of universal voluntary HIV testing and immediate treatment with ART, combined with present prevention approaches, could have a major effect on severe generalised HIV/AIDS epidemics.
1,948 citations