title: The use of natural language processing on narrative medication schedules to compute average weekly dose.
abstract: Medications with non-standard dosing and unstandardized units of measurement make the estimation of prescribed dose difficult from pharmacy dispensing data. A natural language processing tool named the SIG extractor was developed to identify and extract elements from narrative medication instructions to compute average weekly doses (AWDs) for disease-modifying antirheumatic drugs. The goal of this paper is to evaluate the performance of the SIG extractor.
  
  
  
  This agreement study utilized Veterans Health Affairs pharmacy data from 2008 to 2012. The SIG extractor was designed to extract key elements from narrative medication schedules (SIGs) for 17 select medications to calculate AWD, and these medications were categorized by generic name and route of administration. The SIG extractor was evaluated against an annotator-derived reference standard for accuracy, which is the fraction of AWDs accurately computed.
  
  
  
  The overall accuracy was 89% [95% confidence interval (CI) 88%, 90%]. The accuracy was ≥85% for all medications and route combinations, except for cyclophosphamide (oral) and cyclosporine (oral), which were 79% (95%CI 72%, 85%) and 66% (95%CI 58%, 73%), respectively.
  
  
  
  The SIG extractor performed well on the majority of medications, indicating that AWD calculated by the SIG extractor can be used to improve estimation of AWD when dispensed quantity or days' supply is questionable or improbable. The working model for annotating SIGs and the SIG extractor are generalized and can easily be applied to other medications. Copyright © 2016 John Wiley & Sons, Ltd.
authors.affiliation: George E. Wahlen Department of Veterans Affairs Medical Center, Salt Lake City, UT, USA.|University of Utah, Salt Lake City, UT, USA.
authors.forename: Chao-Chin
authors.initials: CC
authors.lastname: Lu
authors.affiliation: George E. Wahlen Department of Veterans Affairs Medical Center, Salt Lake City, UT, USA.|University of Utah, Salt Lake City, UT, USA.
authors.forename: Jianwei
authors.initials: J
authors.lastname: Leng
authors.affiliation: George E. Wahlen Department of Veterans Affairs Medical Center, Salt Lake City, UT, USA.|University of Utah, Salt Lake City, UT, USA.
authors.forename: Grant W
authors.initials: GW
authors.lastname: Cannon
authors.affiliation: George E. Wahlen Department of Veterans Affairs Medical Center, Salt Lake City, UT, USA.|University of Utah, Salt Lake City, UT, USA.
authors.forename: Xi
authors.initials: X
authors.lastname: Zhou
authors.affiliation: University of Utah, Salt Lake City, UT, USA.
authors.forename: Marlene
authors.initials: M
authors.lastname: Egger
authors.affiliation: George E. Wahlen Department of Veterans Affairs Medical Center, Salt Lake City, UT, USA.|University of Utah, Salt Lake City, UT, USA.
authors.forename: Brett
authors.initials: B
authors.lastname: South
authors.affiliation: George E. Wahlen Department of Veterans Affairs Medical Center, Salt Lake City, UT, USA.
authors.forename: Zach
authors.initials: Z
authors.lastname: Burningham
authors.affiliation: George E. Wahlen Department of Veterans Affairs Medical Center, Salt Lake City, UT, USA.
authors.forename: Qing
authors.initials: Q
authors.lastname: Zeng
authors.affiliation: George E. Wahlen Department of Veterans Affairs Medical Center, Salt Lake City, UT, USA.|University of Utah, Salt Lake City, UT, USA.
authors.forename: Brian C
authors.initials: BC
authors.lastname: Sauer
mesh_terms: D018501:Antirheumatic Agents / Q000008:administration & dosage*; D016001:Confidence Intervals; D003520:Cyclophosphamide / Q000008:administration & dosage; D016572:Cyclosporine / Q000008:administration & dosage; D004307:Dose-Response Relationship, Radiation; D004334:Drug Administration Schedule; D006801:Humans; D009323:Natural Language Processing; D010593:Pharmaceutical Services; D015203:Reproducibility of Results; D014481:United States; D014493:United States Department of Veterans Affairs
chemical_list: D018501:Antirheumatic Agents; D016572:Cyclosporine; D003520:Cyclophosphamide
keywords: DMARDs; computing-prescribed medication dose; narrative medication schedule; natural language processing; pharmacoepidemiology; pharmacy data