van der Windt D A, Koes B W, van Aarst M, Heemskerk M A, Bouter L M
Department of General Practice, Faculty of Medicine, Erasmus University, Rotterdam, The Netherlands.
Br J Gen Pract. 2000 May;50(454):371-4.
Conducting a pragmatic randomised trial in primary care is often accompanied by practical problems. Such problems are seldom reported and may constitute useful lessons for researchers planning future trials.
To address the difficulties involved in patient recruitment and to present measures to minimise bias during outcome assessment.
A recently conducted trial comparing the effects of corticosteroid injections and physiotherapy for painful stiff shoulder was used to illustrate problems related to patient recruitment and outcome assessment.
Recruitment of patients was not without difficulties despite careful preparation. Recruitment was discontinued after 20 months, when 109 of the intended 120 patients had been admitted to the trial. The shoulder trial mainly included patient-oriented subjective outcome measures. Subgroup analyses demonstrated that patient preferences might have had some influence on outcome.
General practitioners might be willing or unwilling to participate in research for many reasons. The researcher should take these motivations into account when inviting physicians to take part in research. Strategies to enhance enrolment should be prepared before the start of the trial. When blinding of patients is problematic, patient preferences should be assessed before randomisation and their influence on the outcome studied. Although involving a blinded independent observer enables a more objective assessment of outcome, the success of blinding should be clearly evaluated.
在基层医疗中开展实用随机试验常常伴随着实际问题。此类问题很少被报道，可能会为计划开展未来试验的研究人员提供有益的经验教训。
解决患者招募过程中遇到的困难，并提出在结果评估期间尽量减少偏倚的措施。
以最近一项比较皮质类固醇注射和物理治疗对疼痛性肩周炎疗效的试验为例，说明与患者招募和结果评估相关的问题。
尽管进行了精心准备，但患者招募并非没有困难。在20个月后招募工作停止，此时计划招募的120名患者中有109名被纳入试验。肩周炎试验主要包括以患者为导向的主观结果指标。亚组分析表明，患者偏好可能对结果产生了一些影响。
全科医生可能出于多种原因愿意或不愿意参与研究。研究人员在邀请医生参与研究时应考虑这些动机。在试验开始前应制定提高入组率的策略。当对患者进行盲法处理存在问题时，应在随机分组前评估患者偏好及其对所研究结果的影响。虽然让一名盲法独立观察者参与能够对结果进行更客观的评估，但应明确评估盲法的成功程度。
