Leveraging electronic health records for phenotyping

With the adoption of electronic health records (EHRs) and subsequent increase in the availability of clinical data in electronic form has come the opportunity to use that data for research. While using EHR data for research has been suggested for decades, specific changes in research capabilities in the last few years have exploded their potential. Genome-wide association studies use many more genotype-phenotype pairs to identify associations. The cost of genotyping data has dropped to the point that the cost of creating phenotypes can now be the limiting factor in a study. EHR data can be extracted inexpensively from existing records, overcoming that limit. Other research activities, such as comparative effectiveness research and creating a learning healthcare system, also benefit from analysis using EHR data. Through initiatives like eMERGE and i2b2, researchers have advanced our capabilities and understanding of using EHRs for phenotyping. Challenges remain, and overcoming these challenges will be critical in maximizing the promise of secondary use for EHR data.