Ascertainment of stroke from administrative data to support a pragmatic embedded clinical trial.

The goal of this observational study was to identify stroke hospitalizations using International Classification of Disease (ICD)-10 codes and use these codes to develop an ascertainment algorithm for use in pragmatic clinical trials, reducing or eliminating the need for manual chart adjudication in future. Using VA (Veterans Affairs) electronic medical records, 9959 patient charts with ICD-10 codes indicating stroke were screened and a sample of 304 were adjudicated by three clinical reviewers. Hospitalizations were categorized as stroke or non-stroke and positive predictive value (PPV) was calculated for each ICD-10 code that was sampled.