Title
Facilitating pharmacogenetic studies using electronic health records and natural-language processing: a case study of warfarin.
Abstract
Objective DNA biobanks linked to comprehensive electronic health records systems are potentially powerful resources for pharmacogenetic studies. This study sought to develop natural-language-processing algorithms to extract drug-dose information from clinical text, and to assess the capabilities of such tools to automate the data-extraction process for pharmacogenetic studies. Materials and methods A manually validated warfarin pharmacogenetic study identified a cohort of 1125 patients with a stable warfarin dose, in which 776 patients were managed by Coumadin Clinic physicians, and the remaining 349 patients were managed by their providers. The authors developed two algorithms to extract weekly warfarin doses from both data sets: a regular expression-based program for semistructured Coumadin Clinic notes; and an advanced weekly dose calculator based on an existing medication information extraction system (Med Ex) for narrative providers' notes. The authors then conducted an association analysis between an automatically extracted stable weekly dose of warfarin and four genetic variants of VKORC1 and CYP2C9 genes. The performance of the weekly dose-extraction program was evaluated by comparing it with a gold standard containing manually curated weekly doses. Precision, recall, F-measure, and overall accuracy were reported. Associations between known variants in VKORC1 and CYP2C9 and warfarin stable weekly dose were performed with linear regression adjusted for age, gender, and body mass index. Results The authors' evaluation showed that the Med Ex-based system could determine patients' warfarin weekly doses with 99.7% recall, 90.8% precision, and 93.8% accuracy. Using the automatically extracted weekly doses of warfarin, the authors successfully replicated the previous known associations between warfarin stable dose and genetic variants in VKORC1 and CYP2C9.
Year
DOI
Venue
2011
10.1136/amiajnl-2011-000208
JOURNAL OF THE AMERICAN MEDICAL INFORMATICS ASSOCIATION
Keywords
Field
DocType
linear regression,information extraction,gold standard,association analysis,regular expression,genetics,natural language processing
Pharmacogenetics,Data mining,Pharmacogenetic Study,Body mass index,Warfarin dose,Gold standard,Cohort,Warfarin,Medicine,VKORC1
Journal
Volume
Issue
ISSN
18
4
1067-5027
Citations 
PageRank 
References 
18
1.09
6
Authors
15
Name
Order
Citations
PageRank
Hua Xu132332.99
Min Jiang2181.09
Matt Oetjens3181.09
Erica A Bowton4192.13
Andrea H Ramirez5182.10
Janina M Jeff6191.45
Melissa A. Basford718415.24
Jill M. Pulley812612.84
James D Cowan9302.79
Xiaoming Wang10181.09
Marylyn D. Ritchie1169286.79
Daniel R. Masys1227147.38
Dan M. Roden1317718.14
Dana C. Crawford1413714.54
Joshua C. Denny1593297.43