TY - JOUR
T1 - Reexamining the recommended follow-up interval after obtaining an in-range international normalized ratio value
T2 - Results from the Veterans Affairs Study to Improve Anticoagulation
AU - Rose, Adam J.
AU - Ozonoff, Al
AU - Berlowitz, Dan R.
AU - Ash, Arlene S.
AU - Reisman, Joel I.
AU - Hylek, Elaine M.
N1 - Funding Information: Financial/nonfinancial disclosures: The authors have reported to CHEST the following conflicts of interest: Dr Rose is supported by a Career Development Award from the Health Services Research and Development Service of the US Department of Veterans Affairs. Dr Hylek has received honoraria from Bayer and Bristol-Myers Squibb and has served on advisory boards for Boehringer-Ingelheim, Bristol-Myers Squibb, and Sanofi-Aventis. Drs Ozonoff, Berlowitz, and Ash and Mr Reisman have reported that no potential conflicts of interest exist with any companies/organizations whose products or services may be discussed in this article.
PY - 2011/8/1
Y1 - 2011/8/1
N2 - Background: Patients receiving oral anticoagulation therapy should be tested often enough to optimize control, but excessive testing increases burden and cost. We examined the relationship between follow-up intervals after obtaining an in-range (2.0-3.0) international normalized ratio (INR) and anticoagulation control. Methods: We studied 104,451 patients who were receiving anticoagulation therapy from 100 anticoagulation clinics in the US Veterans Health Administration. Most patients (98,877) had at least one in-range INR followed by another INR within 56 days. For each such patient, we selected the last in-range INR and characterized the interval between this index value and the next INR. The independent variable was the site mean follow-up interval after obtaining an in-range INR. The dependent variable was the site mean risk-adjusted percentage of time in the therapeutic range (TTR). Results: The site mean follow-up interval varied from 25 to 38 days. As the site mean follow-up interval became longer, the risk-adjusted TTR was worse (-0.51% per day, P = .004). This relationship persisted when the index value was the first consecutive in-range INR (-0.63%, P < .001) or the second (-0.58%, P < .001), but not the third or greater (-0.12%, P = .46). Conclusions: Sites varied widely regarding follow-up intervals after obtaining an in-range INR (25-38 days). Shorter intervals were generally associated with better anticoagulation control, but after obtaining a third consecutive in-range value, this relationship was greatly attenuated and no longer statistically significant. Our results suggest that a maximum interval of 28 days after obtaining the first or second in-range value and consideration of a longer interval after obtaining the third or greater consecutive in-range value may be appropriate.
AB - Background: Patients receiving oral anticoagulation therapy should be tested often enough to optimize control, but excessive testing increases burden and cost. We examined the relationship between follow-up intervals after obtaining an in-range (2.0-3.0) international normalized ratio (INR) and anticoagulation control. Methods: We studied 104,451 patients who were receiving anticoagulation therapy from 100 anticoagulation clinics in the US Veterans Health Administration. Most patients (98,877) had at least one in-range INR followed by another INR within 56 days. For each such patient, we selected the last in-range INR and characterized the interval between this index value and the next INR. The independent variable was the site mean follow-up interval after obtaining an in-range INR. The dependent variable was the site mean risk-adjusted percentage of time in the therapeutic range (TTR). Results: The site mean follow-up interval varied from 25 to 38 days. As the site mean follow-up interval became longer, the risk-adjusted TTR was worse (-0.51% per day, P = .004). This relationship persisted when the index value was the first consecutive in-range INR (-0.63%, P < .001) or the second (-0.58%, P < .001), but not the third or greater (-0.12%, P = .46). Conclusions: Sites varied widely regarding follow-up intervals after obtaining an in-range INR (25-38 days). Shorter intervals were generally associated with better anticoagulation control, but after obtaining a third consecutive in-range value, this relationship was greatly attenuated and no longer statistically significant. Our results suggest that a maximum interval of 28 days after obtaining the first or second in-range value and consideration of a longer interval after obtaining the third or greater consecutive in-range value may be appropriate.
UR - http://www.scopus.com/inward/record.url?scp=80051518203&partnerID=8YFLogxK
U2 - https://doi.org/10.1378/chest.10-2738
DO - https://doi.org/10.1378/chest.10-2738
M3 - Article
SN - 0012-3692
VL - 140
SP - 359
EP - 365
JO - Chest
JF - Chest
IS - 2
ER -