School of Public Health, University of California, Berkeley, California, USA.
AIDS. 2010 Mar 13;24(5):621-35. doi: 10.1097/QAD.0b013e328337798a.
OBJECTIVE(S): Few HIV prevention interventions have been evaluated in randomized controlled trials (RCTs). We examined design, implementation, and contextual considerations that may limit detection of a positive or adverse effect in HIV prevention trials.
A systematic review of late phase RCTs for prevention of sexual transmission of HIV that randomly allocated intervention and comparison groups; evaluated interventions to prevent sexual transmission in nonpregnant populations; and reported HIV incidence as the primary or secondary outcome.
PubMed/MEDLINE, other electronic databases, and electronic conference proceedings of recent HIV/AIDS-related conferences were searched to identify published or unpublished trials meeting the inclusion criteria. Descriptive, methodological, and contextual factors were abstracted from each trial.
The review included 37 HIV prevention RCTs reporting on 39 unique interventions. Only six RCTs, all evaluating biomedical interventions, demonstrated definitive effects on HIV incidence. Five of the six RCTs significantly reduced HIV infection: all three male circumcision trials, one trial of sexually transmitted infection treatment and care, and one vaccine trial. One microbicide trial of nonoxynol-9 gel produced adverse results. Lack of statistical power, poor adherence, and diluted versions of the intervention in comparison groups may have been important issues for the other trials that demonstrated 'flat' results.
Almost 90% of HIV prevention trials had 'flat' results, which may be attributable to trial design and/or implementation. The HIV prevention community must not only examine evidence from significant RCTs, but must also examine flat trials and address design and implementation issues that limit detection of an effect.
少数艾滋病毒预防干预措施已经在随机对照试验（RCT）中进行了评估。我们研究了设计、实施和背景因素，这些因素可能会限制艾滋病毒预防试验中阳性或不良效果的检测。
对预防艾滋病毒性传播的后期阶段 RCT 进行系统评价，这些 RCT 随机分配了干预组和对照组；评估了预防非孕妇群体性传播的干预措施；并将艾滋病毒发病率作为主要或次要结局进行报告。
通过 PubMed/MEDLINE、其他电子数据库和最近与艾滋病毒/艾滋病相关会议的电子会议记录，搜索符合纳入标准的已发表或未发表的试验。从每个试验中提取描述性、方法学和背景因素。
综述纳入了 37 项艾滋病毒预防 RCT，报告了 39 项独特的干预措施。只有 6 项 RCT，均评估生物医学干预措施，对艾滋病毒发病率有明确影响。这 6 项 RCT 中的 5 项显著降低了艾滋病毒感染率：所有 3 项男性包皮环切试验、1 项性传播感染治疗和护理试验以及 1 项疫苗试验。1 项非诺孕酯凝胶的杀微生物剂试验产生了不良结果。缺乏统计能力、依从性差以及对照组中干预措施的稀释版本可能是其他显示“平坦”结果的试验的重要问题。
近 90%的艾滋病毒预防试验结果“平坦”，这可能归因于试验设计和/或实施。艾滋病毒预防界不仅必须审查来自重大 RCT 的证据，还必须审查“平坦”试验，并解决限制效果检测的设计和实施问题。
