Thomas Elaine, Croft Peter R, Paterson Susan M, Dziedzic Krysia, Hay Elaine M
Primary Care Sciences Research Centre, Keele University, Keele, North Staffordshire ST5 5BG, UK.
Br J Gen Pract. 2004 Feb;54(499):93-6.
In randomised clinical trials (RCTs), outcome may be influenced by the opinions of the participants about the efficacy of treatments.
To examine how initial treatment preferences of participants in a shoulder pain trial affected functional outcome and future treatment preferences.
Observational cohort study nested within a multicentre, pragmatic RCT of steroid injection versus physiotherapy for unilateral shoulder pain.
Nine general practices in north Staffordshire.
Two hundred and seven adults were randomised in the trial. Disability scores and preferences of the participants for the trial treatments were elicited at two points: prior to randomisation and 6 months post-randomisation. A good functional outcome was defined as at least a halving in the disability score at the 6 months follow-up point.
Pre-randomisation preferences were: 40% for injection and 20% for physiotherapy, and 40% gave no preference. A good outcome was achieved in a higher percentage of participants who gave a pre-randomisation treatment preference compared with those who did not (62% compared with 48% percentage difference = 14%; 95% confidence interval [CI] = -1 to 27%) with similar percentages in each preferred treatment group. However, receiving the preferred treatment did not confer any additional benefit in those who expressed a preference (receiving preferred treatment = 56%; not receiving preferred treatment = 69%). At 6 months post-randomisation, participants with a good, as opposed to poor, outcome were more likely to report as their preferred treatment the one to which they had been randomised, irrespective of pre-randomisation preference and whether the preferred treatment was received.
This analysis suggests that preferences prior to treatment can affect outcome, but that treatment outcome is a stronger influence on post-treatment preferences. We present some empirical evidence to support the statement that treatment preferences can have important effects on the results of RCTs.
在随机临床试验（RCT）中，结局可能会受到参与者对治疗效果看法的影响。
研究肩部疼痛试验中参与者的初始治疗偏好如何影响功能结局和未来的治疗偏好。
一项观察性队列研究，嵌套于一项多中心、实用性随机对照试验中，该试验比较了类固醇注射与物理治疗对单侧肩部疼痛的疗效。
北斯塔福德郡的9家普通诊所。
207名成年人被随机分配到该试验中。在两个时间点收集参与者的残疾评分和对试验治疗的偏好：随机分组前和随机分组后6个月。良好的功能结局定义为在6个月随访时残疾评分至少减半。
随机分组前的偏好为：40%倾向注射，20%倾向物理治疗，40%无偏好。与无随机分组前治疗偏好的参与者相比，有随机分组前治疗偏好的参与者中获得良好结局的比例更高（62%对48%，百分比差异=14%；95%置信区间[CI]=-1至27%），每个偏好治疗组中的比例相似。然而，对于表达了偏好的参与者，接受偏好的治疗并未带来任何额外益处（接受偏好治疗的比例=56%；未接受偏好治疗的比例=69%）。在随机分组后6个月，与结局较差的参与者相比，结局良好的参与者更有可能报告他们被随机分配的治疗为其偏好的治疗，无论随机分组前的偏好如何，也无论是否接受了偏好的治疗。
该分析表明治疗前的偏好会影响结局，但治疗结局对治疗后的偏好影响更大。我们提供了一些实证证据来支持治疗偏好会对随机对照试验结果产生重要影响这一观点。
