The effects of an open design on trial participant recruitment, compliance and retention--a randomized controlled trial comparison with a blinded, placebo-controlled design.
The effects of an open design on trial participant recruitment, compliance and retention--a randomized controlled trial comparison with a blinded, placebo-controlled design.
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DOI：
10.1191/1740774504cn053oa
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发表时间：
2004-01-01
期刊：
影响因子：
--
通讯作者：
McGee, Magnus A
中科院分区：
文献类型：
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作者：
Avenell, Alison;Grant, Adrian M;McGee, Magnus A
背景技术背景：在随机试验中，是否使用安慰剂对照可能没有压倒性的理由。目的：我们评估了开放试验设计的效果（没有安慰剂，人们知道他们是什么片）与一个盲法，安慰剂对照设计的招募，依从性和保留在一个随机试验的继发性骨质疏松性骨折预防。我们在英国一家教学医院招募了70岁或70岁以上的骨折患者，进行了一项营养补充剂安慰剂对照试验，并进行了随机对照比较。随机化是2：1有利于盲法，安慰剂对照trial design.Results：从180名合格的参与者随机接受信息的基础上开放试验设计，134（74.4%）同意参加，相比之下，233（65.1%）的358人随机盲法，安慰剂对照设计（差异9.4%，95%置信区间1.3-17.4%）。不愿意服用安慰剂和希望了解片剂分配是不参加设盲、安慰剂对照设计的原因。片剂依从性无显著差异。开放试验受试者更有可能留在试验中一年（差异13.9%，95%置信区间3.1-24.6%），主要反映了开放试验无片剂组与开放试验片剂组相比的高保留率（差异23.6%，95%置信区间11.9-35.2%）。与设盲、安慰剂对照设计相比，开放试验中报告不良事件的比值比为0.64（95%置信区间为0.28-1.49），报告骨折为0.81（0.36-1.85）.结论：我们的结论是，使用开放试验设计可以提高参与者的招募和保留，从而提高普遍性和统计能力，但退出率在研究分配之间可能不同，并可能威胁到试验的内部有效性。
BACKGROUND: In randomized trials there may be no overriding reason whether or not to have a placebo control.PURPOSE: We assessed the effects of an open trial design (no placebo and people know what tablets they are given) compared with a blinded, placebo-controlled design on recruitment, compliance and retention within a randomized trial of secondary osteoporotic fracture prevention.METHODS: We undertook a randomized controlled comparison nested within a placebo-controlled trial of nutritional supplementation amongst people aged 70 years or over who had previously sustained a fracture, recruited in a UK teaching hospital. Randomization was 2:1 in favour of the blinded, placebo-controlled trial design.RESULTS: From 180 eligible participants randomized to receive information based on the open trial design, 134 (74.4%) consented to take part, compared with 233 (65.1%) of 358 people randomized to the blinded, placebo-controlled design (difference 9.4%, 95% confidence interval 1.3-17.4%). Reluctance to take a placebo and the desire to know tablet allocation were reasons given for not taking part in the blinded, placebo-controlled design. There was no significant difference in tablet compliance. Open trial participants were more likely to remain in the trial for one year (difference 13.9%, 95% confidence interval 3.1-24.6%), mainly reflecting the high retention of the open trial no tablet group compared to the open trial tablet group (difference 23.6%, 95% confidence interval 11.9-35.2%). The odds ratio for reporting an adverse event in the open trial compared to the blinded, placebo-controlled design was 0.64 (95% confidence interval 0.28-1.49), and for reporting a fracture was 0.81 (0.36-1.85).CONCLUSIONS: We conclude that using an open trial design may enhance participant recruitment and retention and thus improve generalizability and statistical power, but withdrawal rates may differ between the study allocations and may threaten the internal validity of the trial.