title: Prompt repeat testing after out-of-range INR values: a quality indicator for anticoagulation care.
abstract: BACKGROUND
  Improved control of oral anticoagulation reduces adverse events. A program of quality measurement is needed for oral anticoagulation. The interval until the next test after an out-of-range International Normalized Ratio (INR) value (the "follow-up interval") could serve as a process of care measure.
  
  
  RESULTS
  We studied 104 451 patients cared for by 100 anticoagulation clinics in the Veterans Health Administration (VA). For each site, we computed the average follow-up interval after low (≤1.5) or high (≥4.0) INR. Our outcome was each site's average anticoagulation control, measured by percent time in therapeutic range (TTR); 59 837 patients (57%) contributed to the low INR analysis, 37 697 (36%) contributed to the high INR analysis, and all patients contributed to the dependent variable (mean site TTR). After a low INR, site mean follow-up interval ranged from 10 to 24 days. Longer follow-up intervals were associated with worse site-level control (1.04% lower for each additional day, P<0.001). After a high INR, site mean follow-up interval ranged from 6 to 18 days, with longer follow-up intervals associated with worse site-level control (1.12% lower for each additional day, P<0.001). These relationships were somewhat attenuated but still highly statistically significant when the proportion of INR values in-range was used as the dependent variable rather than TTR.
  
  
  CONCLUSIONS
  Prompt repeat testing after out-of-range INR values is associated with better anticoagulation control at the site level and could be an important part of a quality improvement effort for oral anticoagulation.
authors.affiliation: Center for Health Quality, Outcomes, and Economic Research, Bedford VA Medical Center, 200 Springs Road, Bedford, MA 01730, USA. adamrose@bu.edu
authors.forename: Adam J
authors.initials: AJ
authors.lastname: Rose
authors.forename: Elaine M
authors.initials: EM
authors.lastname: Hylek
authors.forename: Dan R
authors.initials: DR
authors.lastname: Berlowitz
authors.forename: Arlene S
authors.initials: AS
authors.lastname: Ash
authors.forename: Joel I
authors.initials: JI
authors.lastname: Reisman
authors.forename: Al
authors.initials: A
authors.lastname: Ozonoff
mesh_terms: D000284:Administration, Oral; D000368:Aged; D000925:Anticoagulants / Q000009:adverse effects* / Q000627:therapeutic use*; D001281:Atrial Fibrillation / Q000188:drug therapy*; D005260:Female; D005500:Follow-Up Studies; D006470:Hemorrhage / Q000453:epidemiology / Q000517:prevention & control; D006801:Humans; D019934:International Normalized Ratio / Q000379:methods*; D008297:Male; D008875:Middle Aged; D019984:Quality Indicators, Health Care; D012016:Reference Values; D012189:Retrospective Studies; D012307:Risk Factors; D013997:Time Factors; D014481:United States; D014493:United States Department of Veterans Affairs; D054556:Venous Thromboembolism / Q000188:drug therapy*
chemical_list: D000925:Anticoagulants