title: Storing and Querying Longitudinal Data Sets in an Open Source EHR.
abstract: The cityEHR is an example of an open source EHR system which stores clinical data as collections of XML documents. The records gathered in routine clinical care are a rich source of longitudinal data for use in clinical studies. We describe how the standard language XQuery can be used to identify cohorts of patients, matching specified criteria. We discuss methods for ensuring good data quality and the issues in implementing XML queries on longitudinal data sets.
authors.affiliation: Seven Informatics Ltd, Oxford, UK.
authors.forename: John
authors.initials: J
authors.lastname: Chelsom
authors.affiliation: Seven Informatics Ltd, Oxford, UK.
authors.forename: Naveed
authors.initials: N
authors.lastname: Dogar
mesh_terms: D015331:Cohort Studies; D004282:Documentation / Q000379:methods; D057286:Electronic Health Records / Q000458:organization & administration* / Q000706:statistics & numerical data; D006801:Humans; D016247:Information Storage and Retrieval / Q000379:methods; D008137:Longitudinal Studies
keywords: Cohort Studies; EHR; HL7 CDA; Longitudinal Data; XQuery