JAMIA: EMRs enable genetic study of peripheral artery disease
EMR-based data, used across institutions in a structured way, offer great potential for diverse research studies, including those related to understanding the genetic bases of common diseases, according to new research published in this month's Journal of the American Medical Informatics Association.
Iftikhar J. Kullo, MD, from the Mayo Clinic's divisions of cardiovascular diseases and biomedical informatics and statistics in Rochester, Minn., and colleagues demonstrated the feasibility of leveraging EMRs to launch a genome-wide association study (GWAS) of peripheral artery disease (PAD).
The researchers created a biorepository of DNA and plasma by recruiting patients referred for non-invasive lower extremity arterial evaluation or stress ECG. PAD was defined as a resting/post-exercise ankle-brachial index (ABI) less than or equal to 0.9, a history of lower extremity revascularization, or having poorly compressible leg arteries. Controls were patients without evidence of PAD.
Demographic data and laboratory values were extracted from the EMR. Medication use and smoking status were established by natural language processing of clinical notes. Other risk factors and co-morbidities were ascertained based on ICD-9-CM codes, medication use and laboratory data. The researchers analyzed age, sex, body mass index, race, geographical distribution, risk factors, co-morbidities, smoking status and medications.
According to the authors, of 1,802 patients with an abnormal ABI, 115 had non-atherosclerotic vascular disease, such as vasculitis, Buerger's disease, trauma and embolism (phenocopies) based on ICD-9-CM diagnosis codes, and were excluded.
The PAD cases (66 years, 64 percent men) were older than controls (61 years, 60 percent men) but had similar geographical distribution and ethnic composition. Among PAD cases, 85.6 percent had an abnormal ABI, 13.8 percent had poorly compressible arteries and 0.6 percent had a history of lower extremity revascularization, the authors found.
In a random sample of 95 cases and 100 controls, risk factors and co-morbidities ascertained from EMR-based algorithms had good concordance compared with manual record review; the precision ranged from 67 to 100 percent and recall from 84 to 100 percent.
“This study demonstrates use of the EMR to ascertain phenocopies, phenotype heterogeneity and relevant covariates to enable a GWAS of PAD,” the authors concluded. “Biorepositories linked to EMR may provide a relatively efficient means of conducting GWAS and several significant advantages over traditional approaches to genomic medicine research by simplifying logistics, reducing timelines and overall costs through efficient data acquisition."
Iftikhar J. Kullo, MD, from the Mayo Clinic's divisions of cardiovascular diseases and biomedical informatics and statistics in Rochester, Minn., and colleagues demonstrated the feasibility of leveraging EMRs to launch a genome-wide association study (GWAS) of peripheral artery disease (PAD).
The researchers created a biorepository of DNA and plasma by recruiting patients referred for non-invasive lower extremity arterial evaluation or stress ECG. PAD was defined as a resting/post-exercise ankle-brachial index (ABI) less than or equal to 0.9, a history of lower extremity revascularization, or having poorly compressible leg arteries. Controls were patients without evidence of PAD.
Demographic data and laboratory values were extracted from the EMR. Medication use and smoking status were established by natural language processing of clinical notes. Other risk factors and co-morbidities were ascertained based on ICD-9-CM codes, medication use and laboratory data. The researchers analyzed age, sex, body mass index, race, geographical distribution, risk factors, co-morbidities, smoking status and medications.
According to the authors, of 1,802 patients with an abnormal ABI, 115 had non-atherosclerotic vascular disease, such as vasculitis, Buerger's disease, trauma and embolism (phenocopies) based on ICD-9-CM diagnosis codes, and were excluded.
The PAD cases (66 years, 64 percent men) were older than controls (61 years, 60 percent men) but had similar geographical distribution and ethnic composition. Among PAD cases, 85.6 percent had an abnormal ABI, 13.8 percent had poorly compressible arteries and 0.6 percent had a history of lower extremity revascularization, the authors found.
In a random sample of 95 cases and 100 controls, risk factors and co-morbidities ascertained from EMR-based algorithms had good concordance compared with manual record review; the precision ranged from 67 to 100 percent and recall from 84 to 100 percent.
“This study demonstrates use of the EMR to ascertain phenocopies, phenotype heterogeneity and relevant covariates to enable a GWAS of PAD,” the authors concluded. “Biorepositories linked to EMR may provide a relatively efficient means of conducting GWAS and several significant advantages over traditional approaches to genomic medicine research by simplifying logistics, reducing timelines and overall costs through efficient data acquisition."