| Title | Can We Predict Daily Adherence to Warfarin? Results from the IN-RANGE Study. | | Author(s) | Platt AB, Localio AR, Brensinger CM, Cruess DG, Christie JD, Gross R, Parker CS, Price M, Metlay JP, Cohen A, Newcomb CW, Strom BL, Laskin MS, Kimmel SE | | Institution | (1) Center for Health Equity Research and Promotion, Philadelphia VA Medical Center; | | Source | Chest 2009 Nov 10. | | Abstract | 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: Prospective cohort study of adults initiating warfarin therapy at two anticoagulation clinics (University and VA-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 predict daily nonadherence to warfarin.
RESULTS: We followed 114 subjects for a median of 141 days. Median nonadherence of the participants 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 versus high levels of nonadherence: 4 points or less, median nonadherence 5.8% (IQR 2.3-14.1); 5 points, 9.1% (IQR 5.9-28.6); 6 points, 14.5% (IQR 7.1-24.1); 7 points, 14.7% (IQR 7.0-34.7); 8 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 may, 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. | | Language | ENG | | Pub Type(s) | JOURNAL ARTICLE
| | PubMed ID | 19903973 |
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