title: Giving formulary and drug cost information to providers and impact on medication cost and use: a longitudinal non-randomized study.
abstract: BACKGROUND
  Providers wish to help patients with prescription costs but often lack drug cost information. We examined whether giving providers formulary and drug cost information was associated with changes in their diabetes patients' drug costs and use. We conducted a longitudinal non-randomized evaluation of the web-based Prescribing Guide ( www.PrescribingGuide.com ), a free resource available to Hawaii's providers since 2006, which summarizes the formularies and copayments of six health plans for drugs to treat 16 common health conditions. All adult primary care physicians in Hawaii were offered the Prescribing Guide, and providers who enrolled received a link to the website and regular hardcopy updates.
  
  
  METHODS
  We analyzed prescription claims from a large health plan in Hawaii for 5,883 members with diabetes from 2007 (baseline) to 2009 (follow-up). Patients were linked to 299 "main prescribing" providers, who on average, accounted for >88 % of patients' prescriptions and drug costs. We compared changes in drug costs and use for "study" patients whose main provider enrolled to receive the Prescribing Guide, versus "control" patients whose main provider did not enroll to receive the Prescribing Guide.
  
  
  RESULTS
  In multivariate analyses controlling for provider specialty and clustering of patients by providers, both patient groups experienced similar increases in number of prescriptions (+3.2 vs. +2.7 increase, p = 0.24), and days supply of medications (+141 vs. +129 increase, p = 0.40) averaged across all drugs. Total and out-of-pocket drug costs also increased for both control and study patients. However, control patients showed higher increases in yearly total drug costs of $208 per patient (+$792 vs. +$584 increase, p = 0.02) and in 30-day supply costs (+$9.40 vs. +$6.08 increase, p = 0.03). Both groups experienced similar changes in yearly out-of-pocket costs (+$41 vs + $31 increase, p = 0.36) and per 30-day supply (-$0.23 vs. -$0.19 decrease, p = 0.996).
  
  
  CONCLUSIONS
  Giving formulary and drug cost information to providers was associated with lower increases in total drug costs but not with lower out-of-pocket costs or greater medication use. Insurers and health information technology businesses should continue to increase providers' access to formulary and drug cost information at the point of care.
authors.affiliation: Department of Family Medicine and Community Health, University of Hawaii John A. Burns School of Medicine, 677 Ala Moana Blvd, Ste. 815, Honolulu, HI, 96813, USA. cwtseng@hawaii.edu.|Pacific Health Research and Education Institute, Honolulu, USA. cwtseng@hawaii.edu.|Veteran Affairs Pacific Islands Health Care System, Honolulu, USA. cwtseng@hawaii.edu.
authors.forename: Chien-Wen
authors.identifier: http://orcid.org/0000-0001-7162-2550
authors.initials: CW
authors.lastname: Tseng
authors.affiliation: Division of General Internal Medicine, Department of Medicine, University of California, San Francisco, USA.|Philip R. Lee Institute for Health Policy Studies, University of California, San Francisco, USA.
authors.forename: Grace A
authors.initials: GA
authors.lastname: Lin
authors.affiliation: Biostatistics and Data Management Core, University of Hawaii John A. Burns School of Medicine, Honolulu, USA.
authors.forename: James
authors.initials: J
authors.lastname: Davis
authors.affiliation: Daniel K. Inouye College of Pharmacy, University of Hawai'i at Hilo, Hilo, USA.
authors.forename: Deborah A
authors.initials: DA
authors.lastname: Taira
authors.affiliation: Division of Rheumatology, Department of Medicine, University of California, San Francisco, USA.
authors.forename: Jinoos
authors.initials: J
authors.lastname: Yazdany
authors.affiliation: Pacific Health Research and Education Institute, Honolulu, USA.
authors.forename: Qimei
authors.initials: Q
authors.lastname: He
authors.affiliation: Pacific Health Research and Education Institute, Honolulu, USA.
authors.forename: Randi
authors.initials: R
authors.lastname: Chen
authors.affiliation: Library Business Services, University of California, Los Angeles, USA.
authors.forename: Allison
authors.initials: A
authors.lastname: Imamura
authors.affiliation: Philip R. Lee Institute for Health Policy Studies, University of California, San Francisco, USA.|Division of Pulmonary and Critical Care, Department of Medicine, University of California, San Francisco, USA.
authors.forename: R Adams
authors.initials: RA
authors.lastname: Dudley
keywords: Electronic prescribing; Formularies; Medication use; Out-of-pocket cost; Prescription drug costs