Public health surveillance with electronic medical records: at risk of surveillance bias and overdiagnosis

ARTICLE Public health surveillance consists in the systematic collection, analysis and interpretation of data, closely integrated with the timely dissemination and use of these data to help prevent and control diseases and injuries.1 Surveillance is traditionally conducted with data tailored to address a specific health problem, for instance, data on risk behaviours from periodic health surveys or data on cancers collected in dedicated registries. These data and methods of collection are ‘designed’ for specific surveillance activities.2 In the past two decades, methods of surveillance have radically changed with the development of information technology, making easier the collection of data for public health surveillance.3 In particular, data from health care providers have become highly accessible through electronic medical records (EMRs), which offers fantastic opportunities for the surveillance of several conditions. EMR is a digital record of patient’s health and health care from hospitals, nursing homes, physician’s offices or pharmacies.3 All kinds of medical events are recorded in EMRs, being diagnoses, laboratory results, treatments, drug prescriptions, vital signs or clinical outcomes. EMRs increase the availability of clinical information, can help decision making and improve quality and efficiency of care. Furthermore, shared EMRs are cardinal for the evolution of health professionals’ …