Risk factors for nonadherence to warfarin: results from the IN‐RANGE study

Platt, Alec B.; Localio, A. Russell; Brensinger, Colleen M.; Cruess, Dean G.; Christie, Jason D.; Gross, Robert; Parker, Catherine S.; Price, Maureen; Metlay, Joshua P.; Cohen, Abigail; Newcomb, Craig; Strom, Brian L.; Laskin, Mitchell; Kimmel, Stephen E.

doi:10.1002/pds.1556

Cited by 118 publications

(119 citation statements)

References 27 publications

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“…This is in contrast to previous research, which has found that VTE patients had higher differentials compared to AF patients 45. A possible explanation for this is our VTE patients were on average 10 years younger and younger age has been associated with worse adherence elsewhere 46, 47. Furthermore, as the AF population was more comorbid, VTE patients were likely to recognize the burden of their illness more than AF patients where AF is one of many illnesses.…”

Section: Discussioncontrasting

confidence: 86%

Associations between illness beliefs, medication beliefs, anticoagulation‐related quality of life, and INR control: Insights from the Switching Study

Bartoli-Abdou

Patel

Xie

et al. 2018

Research and Practice in Thrombosis and Haemostasis

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BackgroundAnticoagulation control with vitamin‐K antagonists (VKAs) in patients with atrial fibrillation (AF) or venous thromboembolism (VTE) can be measured using time in therapeutic range (TTR), where TTR >65% is considered good and low TTR may be associated with low adherence.MethodsThis cross‐sectional observational study compared illness beliefs, treatment beliefs, and treatment satisfaction of patients with TTR >75% and TTR <50% using validated tools to determine their association with TTR. Adults requiring chronic VKA therapy were recruited from 2 hospital anticoagulation clinics in London, UK.Results311 patients with TTR >75% and 214 with TTR <50% were recruited. TTR >75% patients had been taking warfarin on average over 2 years longer than TTR <50% patients (P < .001). Statistically significant differences in beliefs were found in all subscales other than in treatment control, general harm, and general overuse. Cluster analysis determined there were 4 distinct clusters of beliefs among patients. Multivariate binary logistic regression found VTE patients were least likely to have poor TTR (OR = 0.49; 95% CI 0.29, 0.77). Patients in the “cautious of therapy and fearful of illness” cluster were most likely to have low TTR (OR = 4.75; 95% CI 2.75, 8.77).ConclusionIllness perceptions, medication beliefs and treatment satisfaction were associated with INR control. VTE patients and those who were accepting of both illness and treatment were most likely to have optimal INR control.

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Section: Discussioncontrasting

confidence: 86%

Associations between illness beliefs, medication beliefs, anticoagulation‐related quality of life, and INR control: Insights from the Switching Study

Bartoli-Abdou

Patel

Xie

et al. 2018

Research and Practice in Thrombosis and Haemostasis

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“…This result indicates that stable patients were more compliant than unstable patients who were not compliant to warfarin therapy, but this result is without a statistically significant difference, P-value = 0.058, Figure 5. These findings are on line with a study that had found poor compliance with warfarin is a common risk factor for warfarin instability leading to serious complications 36,37 . Figure 16.…”

Section: Non-genetic Factorssupporting

confidence: 91%

Genetic and Non-Genetic Factors Association with Warfarin Long Term Therapy Stability in Sudan

Aldahab¹,

Elkhawad²

2016

AJPRHC

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Anticoagulation with warfarin is characterized by a wide inter-individual variations in dose requirements and INR (International Normalised Ratio) stability, as there are evidences that warfarin response variability is associated with CYP2C9 (cytochrome P450, family 2, subfamily C, polypeptide 9) and VKORC1 (Vitamin K epoxide reductase complex1) genetic polymorphisms. Carriers of CYP2C9*2 and VKORC11639G>A variant alleles are at greater risk of unstable anticoagulation therapy. Objectives: This retrospective case control study was directed to analyze the impact of genetic and non-genetic factors on warfarin therapy in Sudanese out-patients who were on long term warfarin therapy. Method: 118 Sudanese outpatients receiving warfarin treatment for at least six months, were interviewed for their non-genetic factors that included age, sex, indication for warfarin therapy, compliance, Vitamin K rich foods intake and concomitant drug therapy, in addition to their blood samples which were taken for DNA extraction and genotyping of CYP2C9*2 and VKORC11639G>A gene polymorphisms to study the genetic factors. INR stability % index was calculated, accordingly patients were classified into 2 groups, stable and unstable groups. Results: The frequencies of VKORC11639G>A alleles in Sudanese out-patients who were on long term warfarin therapy were 70.3% and 29.7% for the VKORC1/G and VKORC1/A alleles respectively. The frequencies of CYP2C9*2 alleles in Sudanese out-patients were 92.4% and 7.6% for CYP2C9*1 and CYP2C9*2 alleles respectively. Variables associated with low INR stability were VKCOR1/AA genotype (p-value = 0.028) and sex (p = 0.017). Variables that showed no association with INR stability were age (p-value = 0.259), compliance (p-value = 0.058). Vitamin K rich foods intake (p-value = 0.743), and mean stable warfarin dose (p-value = 0.439). Conclusion: Polymorphism in warfarin drug target gene VKORC1-11639G>A and sex are important elements of INR stability in Sudanese out-patients on long term warfarin therapy.

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“…Nosotros encontramos similares asociaciones con algunos de estos factores como edad y presencia de tres o más comorbilidades. Otra variable asociada a este grupo fue el "no bajo grado de instrucción", lo cual parecería ser antagónico; sin embargo, podría explicarse por una mayor independencia para tomar decisiones, tener menor confianza en el médico o una inapropiada información médica (28).…”

Section: Discussionunclassified

Factores asociados a la anticoagulación oral óptima en el adulto mayor con fibrilación auricular

et al. 2017

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RESUMENObjetivos: Determinar la calidad del control de la anticoagulación oral y los posibles factores asociados al tiempo de rango terapéutico. Material y métodos: Estudio retrospectivo con grupo control y exploración de posibles variables, realizado en pacientes ≥65 años con fibrilación no valvular e indicación de anticoagulación del Hospital Cayetano Heredia entre el 2011-2013. Se determinó el tiempo de rango terapéutico (TRT) por el método de Rosendaal y se consideró control óptimo (TRT ≥60%) y subóptimo (TRT <60%). Se realizó análisis univariado para los factores. Resultados: La mediana de la edad fue 82,23 años, 74 (51,75%) fueron mujeres. Ciento cuarenta pacientes tuvieron indicación de anticoagulación, 94 (67,14%) iniciaron warfarina, 28 (19,72%) tuvo control óptimo y 66 (46,48%) subóptimo. La edad ≥75 años (OR 25,5; IC: 7,8), no bajo grado de instrucción (OR 8; IC 3,61), ≥3 comorbilidades (OR 4,5; IC 2,33-9,39), discontinuidad terapéutica (OR 2,75; IC 1,44-5,52) y polifarmacia (OR 4,2; IC 2,16-8,80) se asociaron con control subóptimo, mientras que independencia funcional (OR 4,3; IC 2,16-9,47), no deterioro cognitivo (OR 7,8; IC 3,19) y género femenino (OR 3; IC 1,62-5,81) al control óptimo. Conclusiones: Un gran porcentaje de pacientes con indicación de ACO y con bajo riesgo de sangrado no iniciaron terapia anticoagulante; y el 50% de quienes la iniciaron, tuvo un control subóptimo. Los pacientes de mayor edad, con mayor comorbilidad y el uso de múltiples medicamentos se asociaron con control subóptimo; mientras que el género femenino y la independencia funcional se asociaron con control óptimo.PALABRAS CLAVE: Fibrilación atrial, warfarina, anciano, accidente cerebrovascular. (Fuente: DeCS BIREME). SUMMARY Objective:To determine the quality of oral anticoagulation control and the possible factors associated with time to reach therapeutic range. Methods: Retrospective study with a control group in patients ≥65 years old with nonvalvular atrial fibrillation who had indication for oral anticoagulation at Hospital Cayetano Heredia from 2011 to 2013. Time to therapeutic range (TTR) was determined by the Rosendal´s method, an optimal control was defined as TTR ≥60%. A multivariate analysis was performed. Results: Median age was 82.23 years; 74 (51.75%) were females; 140 patients had indication for anticoagulation; 94 (67.14%) started warfarin; 28 (19.72%) had optimal control and 66 did not (46.48%). Age ≥ 75 years (OR 25.5; and no low degree of instruction (OR

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Risk factors for nonadherence to warfarin: results from the IN‐RANGE study

Abstract: SUMMARYBackground-Warfarin is widely used to prevent stroke and venous thromboembolism despite its narrow therapeutic window. Warfarin nonadherence is a substantial problem, but risk factors have not been well elucidated.

Cited by 118 publications

References 27 publications

Associations between illness beliefs, medication beliefs, anticoagulation‐related quality of life, and INR control: Insights from the Switching Study

Associations between illness beliefs, medication beliefs, anticoagulation‐related quality of life, and INR control: Insights from the Switching Study

Genetic and Non-Genetic Factors Association with Warfarin Long Term Therapy Stability in Sudan

Factores asociados a la anticoagulación oral óptima en el adulto mayor con fibrilación auricular

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