Department of Health Care Management and Policy, University of Surrey, Guildford, GU2 7XH, UK.
BMC Med Inform Decis Mak. 2011 Oct 13;11:61. doi: 10.1186/1472-6947-11-61.
The evaluation of demonstration sites set up to provide improved access to psychological therapies (IAPT) comprised the study of all people identified as having common mental health problems (CMHP), those referred to the IAPT service, and a sample of attenders studied in-depth. Information technology makes it feasible to link practice, hospital and IAPT clinic data to evaluate the representativeness of these samples. However, researchers do not have permission to browse and link these data without the patients' consent.
To demonstrate the use of a mixed deterministic-probabilistic method of secure and private record linkage (SAPREL)--to describe selection bias in subjects chosen for in-depth evaluation.
We extracted, pseudonymised and used fuzzy logic to link multiple health records without the researcher knowing the patient's identity. The method can be characterised as a three party protocol mainly using deterministic algorithms with dynamic linking strategies; though incorporating some elements of probabilistic linkage. Within the data providers' safe haven we extracted: Demographic data, hospital utilisation and IAPT clinic data; converted post code to index of multiple deprivation (IMD); and identified people with CMHP. We contrasted the age, gender, ethnicity and IMD for the in-depth evaluation sample with people referred to IAPT, use hospital services, and the population as a whole.
The in IAPT-in-depth group had a mean age of 43.1 years; CI: 41.0-45.2 (n=166); the IAPT-referred 40.2 years; CI: 39.4-40.9 (n=1118); and those with CMHP 43.6 years SEM 0.15. (n=12210). Whilst around 67% of those with a CMHP were women, compared to 70% of those referred to IAPT, and 75% of those subject to in-depth evaluation (Chi square p<0.001). The mean IMD score for the in-depth evaluation group was 36.6; CI: 34.2-38.9; (n=166); of those referred to IAPT 38.7; CI: 37.9-39.6; (n=1117); and of people with CMHP 37.6; CI 37.3-37.9; (n=12143).
The sample studied in-depth were older, more likely female, and less deprived than people with CMHP, and fewer had recorded ethnic minority status. Anonymous linkage using SAPREL provides insight into the representativeness of a study population and possible adjustment for selection bias.
旨在提供更多心理治疗途径的示范基地评估包括对所有被确定患有常见心理健康问题（CMHP）的人、被转介至 IAPT 服务的人以及深入研究的参与者样本进行研究。信息技术使得对实践、医院和 IAPT 诊所数据进行链接以评估这些样本的代表性成为可能。然而，如果没有患者的同意，研究人员是没有权限浏览和链接这些数据的。
展示一种安全且私密的记录链接混合确定性-概率方法（SAPREL）的应用，以描述为深入评估而选择的受试者中的选择偏差。
我们提取、假名化并使用模糊逻辑来链接多个健康记录，而无需研究人员了解患者的身份。该方法可以被描述为一种三方协议，主要使用确定性算法和动态链接策略；尽管包含一些概率链接元素。在数据提供方的安全港中，我们提取了：人口统计学数据、医院使用情况和 IAPT 诊所数据；将邮政编码转换为多个剥夺指数（IMD）；并确定了患有 CMHP 的人。我们比较了深入评估样本的年龄、性别、族裔和 IMD 与转介至 IAPT、使用医院服务和整个人口的情况。
在 IAPT-深入组中，平均年龄为 43.1 岁；置信区间：41.0-45.2（n=166）；IAPT 转介组为 40.2 岁；置信区间：39.4-40.9（n=1118）；CMHP 组为 43.6 岁，SEM 为 0.15（n=12210）。虽然大约 67%的 CMHP 患者为女性，而 IAPT 转介组为 70%，深入评估组为 75%（卡方检验，p<0.001）。深入评估组的平均 IMD 评分为 36.6；置信区间：34.2-38.9；（n=166）；IAPT 转介组为 38.7；置信区间：37.9-39.6；（n=1117）；CMHP 组为 37.6；置信区间 37.3-37.9；（n=12143）。
与 CMHP 患者相比，深入研究的样本年龄更大，更有可能为女性，贫困程度更低，记录少数民族身份的比例也更低。使用 SAPREL 进行匿名链接提供了对研究人群代表性的深入了解，并可能对选择偏差进行调整。
