title: Warfarin time in therapeutic range and its impact on healthcare resource utilization and costs among patients with nonvalvular atrial fibrillation.
abstract: BACKGROUND
  Warfarin is efficacious for reducing stroke risk among patients with nonvalvular atrial fibrillation (NVAF). However, the efficacy and safety of warfarin are influenced by its time in therapeutic range (TTR).
  
  
  OBJECTIVE
  To assess differences in healthcare resource utilization and costs among NVAF patients with low (<60%) and high (≥60%) warfarin TTRs in an integrated delivery network (IDN) setting.
  
  
  METHODS
  Patients with NVAF were identified from an electronic medical record database. Patients were required to have ≥6 international normalized prothrombin time ratio (INR) tests. NVAF patients were grouped into two cohorts: those with warfarin TTR <60% (low TTR) and those with warfarin TTR ≥60% (high TTR). Healthcare resource utilization and costs were evaluated during a 12 month follow-up period. Multivariable regressions were used to assess the impact of different warfarin TTRs on healthcare costs.
  
  
  RESULTS
  Among the study population, greater than half (54%, n = 1595) had a low TTR, and 46% (n = 1356) had a high TTR. Total all-cause healthcare resource utilization was higher among patients in the low TTR cohort vs. the high TTR cohort (number of encounters: 70.2 vs. 56.1, p < 0.001). After adjusting for patient characteristics, total all-cause healthcare costs and stroke-related healthcare costs were $2398 (p < 0.001) and $687 (p = 0.02) higher, respectively, for patients in the low TTR cohort vs. the high TTR cohort.
  
  
  CONCLUSIONS
  In this retrospective study, we were only able to evaluate the association and not the causality between healthcare resource utilization and costs with the different warfarin TTRs.
  
  
  CONCLUSIONS
  Many warfarin-treated NVAF patients have a low warfarin TTR. NVAF patients with low vs. patients with high warfarin TTR used healthcare resources to a greater extent, which was reflected in higher healthcare costs.
authors.affiliation: a a Ochsner Health System, Department of Hospital Medicine , New Orleans , LA , USA.
authors.forename: Steve
authors.initials: S
authors.lastname: Deitelzweig
authors.affiliation: b b Geisinger Health System, Enterprise Pharmacy , Danville , PA , USA.
authors.forename: Michael
authors.initials: M
authors.lastname: Evans
authors.affiliation: c c Bristol-Myers Squibb, Health Economics & Outcomes Research , Plainsboro , NJ , USA.
authors.forename: Eric
authors.initials: E
authors.lastname: Hillson
authors.affiliation: d d Pfizer Inc., Global Value & Health - Outcomes & Evidence , New York , NY , USA.
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Trocio
authors.affiliation: c c Bristol-Myers Squibb, Health Economics & Outcomes Research , Plainsboro , NJ , USA.
authors.forename: Amanda
authors.initials: A
authors.lastname: Bruno
authors.affiliation: e e Pfizer Inc., US Medical Affairs , New York , NY , USA.
authors.forename: Wilson
authors.initials: W
authors.lastname: Tan
authors.affiliation: f f Novosys Health, Health Economics and Outcomes Research , Green Brook , NJ , USA.
authors.forename: Melissa
authors.initials: M
authors.lastname: Lingohr-Smith
authors.affiliation: c c Bristol-Myers Squibb, Health Economics & Outcomes Research , Plainsboro , NJ , USA.
authors.forename: Prianka
authors.initials: P
authors.lastname: Singh
authors.affiliation: f f Novosys Health, Health Economics and Outcomes Research , Green Brook , NJ , USA.
authors.forename: Jay
authors.initials: J
authors.lastname: Lin
mesh_terms: D000328:Adult; D000368:Aged; D000925:Anticoagulants / Q000627:therapeutic use*; D001281:Atrial Fibrillation / Q000097:blood / Q000188:drug therapy*; D005260:Female; D017048:Health Care Costs; D006295:Health Resources / Q000706:statistics & numerical data*; D006801:Humans; D019934:International Normalized Ratio; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D013997:Time Factors; D014859:Warfarin / Q000627:therapeutic use*
chemical_list: D000925:Anticoagulants; D014859:Warfarin
keywords: Costs; Healthcare systems; International normalized ratio; Nonvalvular atrial fibrillation; Warfarin