Stroke Risk Calculators in the Era of Electronic Health Records Linked to Administrative Databases

Abstract

Medicine is a science of uncertainty and an art of probability . —Sir William Osler, 1904 Electronic health records (EHRs) linked to administrative databases can unlock the potential of clinical data by overcoming limitations of current cohort-derived risk calculators. EHRs can facilitate implementation of risk-based approaches, whereas current manual or web-based risk calculators pose prohibitive practical barriers to widespread use. We discuss how EHRs can be used: (1) To derive increasingly precise risk equations calibrated to the populations in which they will be applied; (2) To facilitate communication of individual risk to patients; and (3) To provide population-based risk information for researchers, administrators, and policymakers. Several risk calculators directly predict the outcome of stroke.1–3 Stroke is also included as part of a composite outcome in other calculators,4 an approach that may grow in popularity as the concept of stroke as a cardiovascular disease (CVD) risk equivalent becomes more widely accepted. Guidelines state that the level of stroke and CVD risk should inform decision-making about initiating treatments such as aspirin or lipid-lowering agents.5 These strategies are based on the observation that the respective relative risk reduction of aspirin and statin therapies is similar for most subpopulations, and therefore the absolute benefit of treatment is proportional to the absolute risk of stroke or coronary heart disease. Because clinicians do not accurately estimate cardiovascular risk,6,7 adhering to these guidelines requires the use of explicit risk calculators. At least 110 stroke and CVD risk scoring methods exist.8 Early systems typically relied on a points-based system that required clinicians to manually calculate the sum of points associated with various risk factors. More recent calculators allow clinicians to input parameters directly into a website that uses a multivariate equation to predict risk. A recent study comparing 2 …