Men who have sex with men (MSM) remain at great risk for HIV infection. Program planners and policy makers need descriptions of interventions and quantitative estimates of intervention effects to make informed decisions concerning prevention funding and research. The number of intervention strategies for MSM that have been examined with strong research designs has increased substantially in the past few years.
1. To locate and describe outcome studies evaluating the effects of behavioral HIV prevention interventions for MSM.
2. To summarize the effectiveness of these interventions in reducing unprotected anal sex.
3. To identify study characteristics associated with effectiveness.
4. To identify gaps and indicate future research, policy, and practice needs.
We searched electronic databases, current journals, manuscripts submitted by researchers, bibliographies of relevant articles, conference proceedings, and other reviews for published and unpublished reports from 1988 through December 2007. We also asked researchers working in HIV prevention about new and ongoing studies.
Studies were considered in scope if they examined the effects of behavioral interventions aimed at reducing risk for HIV or STD transmission among MSM. We reviewed studies in scope for criteria of outcome relevance (measurement of at least one of a list of behavioral or biologic outcomes, e.g., unprotected sex or incidence of HIV infections) and methodologic rigor (randomized controlled trials or certain strong quasi-experimental designs with comparison groups).
Data collection and analysis
We used fixed and random effects models to summarize rate ratios (RR) comparing intervention and control groups with respect to count outcomes (number of occasions of or partners for unprotected anal sex), and corresponding prevalence ratios (PR) for dichotomous outcomes (any unprotected anal sex vs. none). We used published formulas to convert effect sizes and their variances for count and dichotomous outcomes where necessary. We accounted for intraclass correlation (ICC) in community-level studies and adjusted for baseline conditions in all studies. We present separate results by intervention format (small group, individual, or community-level) and by type of intervention delivered to the comparison group (minimal or no HIV prevention in the comparison condition versus standard or other HIV prevention in the comparison condition). We examine rate ratios stratified according to characteristics of participants, design, implementation, and intervention content. For small group and individual-level interventions we used a stepwise selection process to identify a multivariable model of predictors of reduction in occasions of or partners for unprotected anal sex. We used funnel plots to examine publication bias, and Q (a chi-squared statistic with degrees of freedom = number of interventions minus 1) to test for heterogeneity.
We found 44 studies evaluating 58 interventions with 18,585 participants. Formats included 26 small group interventions, 21 individual-level interventions, and 11 community-level interventions. Sixteen of the 58 interventions focused on HIV-positives. The 40 interventions that were measured against minimal to no HIV prevention intervention reduced occasions of or partners for unprotected anal sex by 27% (95% confidence interval [CI] = 15% to 37%). The other 18 interventions reduced unprotected anal sex by 17% beyond changes observed in standard or other interventions (CI = 5% to 27%).
Intervention effects were statistically homogeneous, and no independent variable was statistically significantly associated with intervention effects at alpha=.05. However, a multivariable model selected by backward stepwise elimination identified four study characteristics associated with reduction in occasions of or partners for unprotected anal sex among small group and individual-level interventions at alpha=.10. The most favorable reductions in episodes of or partners for unprotected anal sex (33% to 35% decreases) were observed among studies with count outcomes, those with shorter intervention spans (<=1 month), those with better retention in the intervention condition than in the comparison condition, and those with minimal to no HIV prevention intervention delivered to the comparison condition.
Because there were only 11 community-level studies we did not search for a multivariable model for community-level interventions. In stratified analyses including only one variable at a time, the greatest reductions (40% to 54% decreases) in number of episodes of or partners for unprotected anal sex among community-level interventions were observed among studies where groups were assigned randomly rather than by convenience, studies with shorter recall periods and longer follow-up, studies with more than 25% non-gay identifying MSM, studies in which at least 90% of participants were white, and studies in which the intervention addressed development of personal skills.
Behavioral interventions reduce self-reported unprotected anal sex among MSM. These results indicate that HIV prevention for this population can work and should be supported.
Results of previous studies provide a benchmark for expectations in new studies. Meta-analysis can inform future design and implementation in terms of sample size, target populations, settings, goals for process measures, and intervention content.
When effects differ by design variables, which are deliberately selected and planned, awareness of these characteristics may be beneficial to future designs. Researchers designing future small group and individual-level studies should keep in mind that to date, effects of the greatest magnitude have been observed in studies that used count outcomes and a shorter intervention span (up to 1 month).
Among small group and individual-level studies, effects were also greatest when the comparison condition included minimal to no HIV prevention content. Nevertheless, statistically significant favorable effects were also seen when the comparison condition included standard or other HIV prevention content. Researchers choosing the latter option for new studies should plan for larger sample sizes based on the smaller expected net intervention effect noted above.
When effects differ by implementation variables, which become evident as the study is conducted but are not usually selected or planned, caution may be advised so that future studies can reduce bias. Because intervention effects were somewhat stronger (though not statistically significantly so) in studies with a greater attrition in the comparison condition, differential retention may be a threat to validity. Extra effort should be given to retaining participants in comparison conditions.
Among community-level interventions, intervention effects were strongest among studies with random assignment of groups or communities. Therefore the inclusion of studies where assignment of groups or communities was by convenience did not exaggerate the summary effect. The greater effectiveness of interventions including more than 25% non-gay identifying MSM suggests that when they can be reached, these men may be more responsive than gay-identified men to risk reduction efforts. Non-gay identified MSM may have had less exposure to previous prevention messages, so their initial exposure may have a greater impact.
The greater effectiveness of interventions that include efforts to promote personal skills such as keeping condoms available and behavioral self-management indicates that such content merits strong consideration in development and delivery of new interventions for MSM. And the finding that interventions were most effective for majority white populations underscores the critical need for effective interventions for MSM of African and Latino descent.
Further research measuring the incidence of HIV and other STDs is needed. Because most studies were conducted among mostly white men in the US and Europe, more evaluations of interventions are needed for African American and Hispanic MSM as well as MSM in the developing world. More research is also needed to further clarify which behavioral strategies (e.g., reducing unprotected anal sex, having oral sex instead of anal sex, reducing number of partners, avoiding serodiscordant partners, strategic positioning, or reducing anal sex even with condom use) are most effective in reducing transmission among MSM, the messages most effective in promoting these behaviors, and the methods and settings in which these messages can be most effectively delivered.
「改變危險性行為(sexual risk behaviors)」的介入性處置以預防男男性交者的人類免疫缺乏病毒感染
男男性交者(men who have sex with men, MSM)一直是人類免疫缺乏病毒感染的高危險群方案規劃者以及政策制定者有必要知道介入措施的內容以及其量化的效果，以因應預防效果作出正確的決策。
1. 找出及描述關於男男性交者的行為及社會介入性處置的研究結果。 2. 統整這些男男性交者的介入性處置效果。 3. 依據介入性處置與參與者的特性，將研究結果分層。 4. 找出研究缺陷，且指出未來所需的研究、政策與實行。
我們搜尋了電子資料庫(包括Medline、PsycInfo等)、數種目前發行的期刊(AIDS、AIDS and Behavior、AIDS Education and Prevention、American Journal of Public Health、Journal of Acquired Immune Deficiency Syndromes等)、研究者所投稿的研究初稿、相關文章的參考書目、以及其他發表的文獻回顧，以及1988年至1997年間發表及未發表的研究報告。
只要研究目標是評估行為介入性處置能否減少人類免疫缺乏病毒或性病(sexually transmitted diseases, STD)傳染的研究，我們回顧研究的範圍為有相關結果(至少衡量一項清單上的行為或生物的結果，如不安全的性行為，HIR 感染率)並且研究方法嚴謹(隨機控制試驗或一些有對照組的半實驗設計)之研究
截至1998年6月為止，我們收案了13個合於收案條件且有關男男性交者的研究。其中1個研究是針對在人類免疫缺乏病毒採樣試驗後對情緒憂傷(emotional distress)的影響，而無性行為結果的報告，因而剔除。另外12個研究(7個為小規模介入性置處，3個為社區規模介入性處置，2個為獨立個體介入性處置)報告了介入性處置對於不安全性行為的效果。因為僅有少數研究報告保險套使用的所造成的影響(3個研究)、不管保險套使用與否對性伴侶數目的影響(4個研究)、或是對人類免疫缺乏病毒及性病發生率的影響(1個研究，該研究無感染發生)，我們此次並未強調這些研究的結果。 在本篇評論性文章中，我們將發表目前在考科藍軟體(Cochrane RevMan software)內所收案的試驗做統計，且在下列情形下做進一步完整的分析：收案社區規模型研究、可對基本情形做校正、可由更多樣的統計算式計算效果強度(effect size)(例：單因子變異數分析(oneway ANOVA)做F統計量(Fstatistic))、可同時進行連續性及二分法結果(continuous and dichotomous outcome)做統合分析。依據不安全性行為的盛行率，將獲得的結論以「高風險行為的減少」表達。 最後我們也提供分層分析的結果，包括：介入性處置的內容(人際溝通技巧的有無)、介入性處置的型式(社區規模vs.小規模或是獨立個體)、以及參與者的平均年齡(23～31歲vs. 32～36歲)。
介入性處置效果對減少不安全性行為的是有益的(odds c 0.73)，且具統計學意義(C1：0.60～0.88)，換句話說，發生不安全性行為的男性比率可下降23%。效果的量測在各個研究間具同質性(homogeneous)，下列幾種情形則稍微更具有益處：社區規模的介入性處置、介入性處置應用於20餘歲(相較於30餘歲)、有提升人際溝通技巧者。
這些研究都顯示，介入性處置可以使男男性交者的感染風險下降。然而就人類免疫缺乏病毒在第I區國家(Pattern I countries)的流行病學而言，這些嚴謹對照的介入性處置研究人數不多卻是令人格外注意。對於男男性交者的人類免疫缺乏病毒預防方法，仍需要更多、更嚴謹的評估，包括介入性處置的內容、族群特性、方法學特性等。
此翻譯計畫由臺灣國家衛生研究院(National Health Research Institutes, Taiwan)統籌。
行為的介入性處置可以減少男男性交者感染人類免疫缺乏病毒的機會，但仍需更多的研究來找出最好的方式。 使用保險套可以顯著減少男男性交者感染人類免疫缺乏病毒的風險。而減少不安全性行為的介入性處置包括：個別會談、社會與行為支持(例：同儕教育、自信與人際關係支持、討論意見及信仰、錄影帶等)。小規模族群與社區規模的介入性處置也被嘗試(像是團體諮商或工作坊、社區內的介入性處置、訓練社區內的領導者)。 本文獻回顧發現，這些介入性處置行為都可顯著減少男男性交者的風險，但仍需要更多研究來找出更具效果的策略及方法。