Moscucci M, Byrne L, Weintraub M, Cox C
Clin Pharmacol Ther. 1987 Mar;41(3):259-65. doi: 10.1038/clpt.1987.26.
We administered a questionnaire to assess maintenance of patients' blindness at the end of a double-blind clinical trial of Osmotic Release Oral System phenylpropanolamine (PPA) vs. placebo in mild obesity. Seventy-four percent of placebo participants and 43% of PPA participants guessed their treatment correctly. Appetite control was the most frequently reported basis for guessing PPA, even by placebo participants. Lack of adverse drug reactions was the most frequently reported basis for guessing placebo, even by PPA participants. Participants receiving either PPA or placebo and guessing PPA lost more weight, had less diet difficulty, and had more adverse drug reactions than had participants receiving either PPA or placebo and guessing placebo. Although blindness was probably maintained in the PPA group, the placebo group seems to have been, at least at the study's end, unblinded. These results suggest that in double-blind studies, differences in outcome or incidence of adverse drug reactions may act as unblinding factors.
在一项关于渗透释放口服系统苯丙醇胺（PPA）与安慰剂治疗轻度肥胖的双盲临床试验结束时，我们进行了一项问卷调查，以评估患者是否维持了盲态。74%的安慰剂组参与者和43%的PPA组参与者正确猜出了他们所接受的治疗。即使是安慰剂组参与者，食欲控制也是最常被报告的猜出PPA的依据。即使是PPA组参与者，缺乏药物不良反应也是最常被报告的猜出安慰剂的依据。与接受PPA或安慰剂且猜出是安慰剂的参与者相比，接受PPA或安慰剂且猜出是PPA的参与者体重减轻更多、饮食困难更少，但药物不良反应更多。尽管PPA组可能维持了盲态，但安慰剂组似乎至少在研究结束时已经破盲。这些结果表明，在双盲研究中，结果差异或药物不良反应发生率可能成为破盲因素。
