The CLEF Chronicle: Patient Histories Derived from Electronic Health Records

Electronic patient records are typically optimised for delivering care to a single patient. They omit significant information that the care team can infer whilst including much of only transient value. They are secondarily an indelible legal record, comprised of heterogeneous documents reflecting local institutional processes as much as, or more than, the course of the patient's illness. By contrast, the CLEF Chronicle is a unified, formal and parsimonious representation of how a patient's illness and treatments unfold through time. Its primary goal is efficient querying of aggregated patient data for clinical research, but it also supports summarisation of individual patients and resolution of co-references amongst clinical documents. It is implemented as a semantic network compliant with a generic temporal object model whose specifics are derived from external sources of clinical knowledge organised around ontologies. We describe the reconstruction of patient chronicles from clinical records and the subsequent definition and execution of sophisticated clinical queries across populations of chronicles. We also outline how clinical simulations are used to test and refine the object model. Finally, we discuss a range of engineering and theoretical challenges raised by our work.