Electronic Health Records (EHR) are generated from clinical routine care recording valuable information of broad patient populations, which provide plentiful opportunities for improving patient management and intervention strategies in clinical practice. To exploit the enormous potential of EHR data, a popular EHR data analysis paradigm in machine learning is EHR representation learning, which first leverages the individual patient's EHR data to learn informative representations by a backbone, and supports diverse health-care downstream tasks grounded on the representations. Unfortunately, such a paradigm fails to access the in-depth analysis of patients' relevance, which is generally known as cohort studies in clinical practice. Specifically, patients in the same cohort tend to share similar characteristics, implying their resemblance in medical conditions such as symptoms or diseases. In this paper, we propose a universal COhort Representation lEarning (CORE) framework to augment EHR utilization by leveraging the fine-grained cohort information among patients. In particular, CORE first develops an explicit patient modeling task based on the prior knowledge of patients' diagnosis codes, which measures the latent relevance among patients to adaptively divide the cohorts for each patient. Based on the constructed cohorts, CORE recodes the pre-extracted EHR data representation from intra- and inter-cohort perspectives, yielding augmented EHR data representation learning. CORE is readily applicable to diverse backbone models, serving as a universal plug-in framework to infuse cohort information into healthcare methods for boosted performance. We conduct an extensive experimental evaluation on two real-world datasets, and the experimental results demonstrate the effectiveness and generalizability of CORE.

翻译：电子健康记录（EHR）源自临床常规护理，记录了广泛患者群体的宝贵信息，为改进临床实践中的患者管理和干预策略提供了丰富机会。为挖掘EHR数据的巨大潜力，机器学习中一种流行的EHR数据分析范式是EHR表征学习，它首先利用单个患者的EHR数据通过主干网络学习信息性表征，并基于这些表征支持多种下游医疗任务。然而，该范式无法深入分析患者间的相关性，这在临床实践中通常被称为群体研究。具体而言，同一群体中的患者往往具有相似特征，这暗示了他们在症状或疾病等医学状况上的相似性。本文提出了一种通用的群体表征学习（CORE）框架，通过利用患者间的细粒度群体信息来增强EHR的利用率。具体而言，CORE首先基于患者诊断代码的先验知识开发了一个显式患者建模任务，该任务衡量患者间的潜在相关性，从而为每位患者自适应划分群体。基于构建的群体，CORE从群体内和群体间两个角度重新编码预提取的EHR数据表征，从而增强EHR数据表征学习。CORE可轻松应用于多种主干模型，作为一种通用插件式框架，将群体信息注入医疗方法中以提升性能。我们在两个真实数据集上进行了广泛的实验评估，实验结果表明了CORE的有效性和泛化能力。