Gulliford Martin C, van Staa Tjeerd P, McDermott Lisa, McCann Gerard, Charlton Judith, Dregan Alex
Department of Primary Care and Public Health Sciences, King's College London, Capital House, 42 Weston St, London SE1 3QD, UK.
Trials. 2014 Jun 11;15:220. doi: 10.1186/1745-6215-15-220.
There is growing interest in conducting clinical and cluster randomized trials through electronic health records. This paper reports on the methodological issues identified during the implementation of two cluster randomized trials using the electronic health records of the Clinical Practice Research Datalink (CPRD).
Two trials were completed in primary care: one aimed to reduce inappropriate antibiotic prescribing for acute respiratory infection; the other aimed to increase physician adherence with secondary prevention interventions after first stroke. The paper draws on documentary records and trial datasets to report on the methodological experience with respect to research ethics and research governance approval, general practice recruitment and allocation, sample size calculation and power, intervention implementation, and trial analysis.
We obtained research governance approvals from more than 150 primary care organizations in England, Wales, and Scotland. There were 104 CPRD general practices recruited to the antibiotic trial and 106 to the stroke trial, with the target number of practices being recruited within six months. Interventions were installed into practice information systems remotely over the internet. The mean number of participants per practice was 5,588 in the antibiotic trial and 110 in the stroke trial, with the coefficient of variation of practice sizes being 0.53 and 0.56 respectively. Outcome measures showed substantial correlations between the 12 months before, and after intervention, with coefficients ranging from 0.42 for diastolic blood pressure to 0.91 for proportion of consultations with antibiotics prescribed, defining practice and participant eligibility for analysis requires careful consideration.
Cluster randomized trials may be performed efficiently in large samples from UK general practices using the electronic health records of a primary care database. The geographical dispersal of trial sites presents a difficulty for research governance approval and intervention implementation. Pretrial data analyses should inform trial design and analysis plans.
Current Controlled Trials ISRCTN 47558792 and ISRCTN 35701810 (both registered on 17 March 2010).
通过电子健康记录开展临床和整群随机试验的兴趣与日俱增。本文报告了在利用临床实践研究数据链（CPRD）的电子健康记录实施两项整群随机试验过程中发现的方法学问题。
两项试验在初级保健中完成：一项旨在减少急性呼吸道感染时不适当的抗生素处方；另一项旨在提高医生对首次中风后二级预防干预措施的依从性。本文利用文献记录和试验数据集，报告了在研究伦理和研究治理批准、全科医疗招募与分配、样本量计算与效能、干预实施以及试验分析方面的方法学经验。
我们获得了英格兰、威尔士和苏格兰150多个初级保健机构的研究治理批准。抗生素试验招募了104个CPRD全科医疗诊所，中风试验招募了106个，目标诊所数量在六个月内招募完成。干预措施通过互联网远程安装到实践信息系统中。抗生素试验中每个诊所的平均参与者数量为5588人，中风试验中为110人，诊所规模的变异系数分别为0.53和0.56。结果测量显示干预前后12个月之间存在显著相关性，系数范围从舒张压的0.42到开具抗生素处方的会诊比例的0.91，定义用于分析的诊所和参与者资格需要仔细考虑。
利用初级保健数据库的电子健康记录，在来自英国全科医疗的大样本中可以高效地进行整群随机试验。试验地点的地理分散给研究治理批准和干预实施带来了困难。试验前的数据分析应为试验设计和分析计划提供信息。
当前受控试验ISRCTN 47558792和ISRCTN 35701810（均于2010年3月17日注册）。
