TY - JOUR
T1 - Can we predict daily adherence to warfarin?
T2 - Results from the international normalized ratio adherence and genetics (IN-RANGE) study
AU - Platt, Alec B.
AU - Russell Localio, A.
AU - Brensinger, Colleen M.
AU - Cruess, Dean G.
AU - Christie, D.
AU - Gross, Robert
AU - Parker Maureen- Price, Catherine S.
AU - Metlay, Joshua P.
AU - Cohen, Abigail
AU - Newcomb, Craig W.
AU - Strom, Brian L.
AU - Laskin, Mitchell S.
AU - Kimmel, Stephen E.
N1 - Funding Information:
Funding/Support: The IN-RANGE study was supported by grants from the National Institutes of Health [R01-HL66176] and the Agency for Health Research and Quality [ P01-HS11530 ]. Dr Kimmel was also supported by P20RR020741 and K24HL070936 .
Funding Information:
Financial/nonfinancial disclosures: The authors have reported to CHEST the following conflicts of interest: Dr Kimmel has served as a consultant and/or received research funding from several pharmaceutical companies, including Pfizer, Merck, Novartis, GlaxoSmithKline, Centocor, and Bayer, all unrelated to this paper. Dr Kimmel has received investigator-initiated research funding from the National Institutes of Health, the Agency for Health Research and Quality, and the Aetna Foundation for warfarin research. Dr Gross has served as a consultant and/or received research funding from GlaxoSmithKline and Bristol-Myers Squibb, and Dr Strom has served as a consultant to Bristol-Myers Squibb and other pharmaceutical companies, all unrelated to this paper. Drs Platt, Localio, Cruess, Christie, Parker, Metlay, and Cohen; Mss Brensinger and Price; and Messrs Newcomb and Laskin have reported that no potential conflicts of interest exist with any companies/organizations whose products or services may be discussed in this article.
PY - 2010/4/1
Y1 - 2010/4/1
N2 - Background: Warfarin is the primary therapy to prevent stroke and venous thromboembolism. Significant periods of nonadherence frequently go unreported by patients and undetected by providers. Currently, no comprehensive screening tool exists to help providers assess the risk of nonadherence at the time of initiation of warfarin therapy. Methods: This article reports on a prospective cohort study of adults initiating warfarin therapy at two anticoagulation clinics (university- and Veterans Affairs-affiliated). Nonadherence, defined by failure to record a correct daily pill bottle opening, was measured daily by electronic pill cap monitoring. A multivariable logistic regression model was used to develop a point system to pre-dict daily nonadherence to warfarin. Results: We followed 114 subjects for a median of 141 days. Median nonadherence of the partici-pants was 14.4% (interquartile range [IQR], 5.8-33.8). A point system, based on nine demographic, clinical, and psychosocial factors, distinguished those demonstrating low vs high levels of nonad-herence: four points or fewer, median nonadherence 5.8% (IQR, 2.3-14.1); five points, 9.1% (IQR, 5.9-28.6); six points, 14.5% (IQR, 7.1-24.1); seven points, 14.7% (IQR, 7.0-34.7); and eight points or more, 29.3% (IQR, 15.5-41.9). The model produces a c-statistic of 0.66 (95% CI, 0.61-0.71), suggesting modest discriminating ability to predict day-level warfarin nonadherence. Conclusions: Poor adherence to warfarin is common. A screening tool based on nine demographic, clinical, and psychosocial factors, if further validated in other patient populations, may help to identify groups of patients at lower risk for nonadherence so that intensified efforts at increased monitoring and intervention can be focused on higher-risk patients.
AB - Background: Warfarin is the primary therapy to prevent stroke and venous thromboembolism. Significant periods of nonadherence frequently go unreported by patients and undetected by providers. Currently, no comprehensive screening tool exists to help providers assess the risk of nonadherence at the time of initiation of warfarin therapy. Methods: This article reports on a prospective cohort study of adults initiating warfarin therapy at two anticoagulation clinics (university- and Veterans Affairs-affiliated). Nonadherence, defined by failure to record a correct daily pill bottle opening, was measured daily by electronic pill cap monitoring. A multivariable logistic regression model was used to develop a point system to pre-dict daily nonadherence to warfarin. Results: We followed 114 subjects for a median of 141 days. Median nonadherence of the partici-pants was 14.4% (interquartile range [IQR], 5.8-33.8). A point system, based on nine demographic, clinical, and psychosocial factors, distinguished those demonstrating low vs high levels of nonad-herence: four points or fewer, median nonadherence 5.8% (IQR, 2.3-14.1); five points, 9.1% (IQR, 5.9-28.6); six points, 14.5% (IQR, 7.1-24.1); seven points, 14.7% (IQR, 7.0-34.7); and eight points or more, 29.3% (IQR, 15.5-41.9). The model produces a c-statistic of 0.66 (95% CI, 0.61-0.71), suggesting modest discriminating ability to predict day-level warfarin nonadherence. Conclusions: Poor adherence to warfarin is common. A screening tool based on nine demographic, clinical, and psychosocial factors, if further validated in other patient populations, may help to identify groups of patients at lower risk for nonadherence so that intensified efforts at increased monitoring and intervention can be focused on higher-risk patients.
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U2 - 10.1378/chest.09-0039
DO - 10.1378/chest.09-0039
M3 - Article
C2 - 19903973
AN - SCOPUS:77950804766
SN - 0012-3692
VL - 137
SP - 883
EP - 889
JO - CHEST
JF - CHEST
IS - 4
ER -