Assessment of anticoagulation knowledge and adherence in patients with atrial fibrillation (2023)


posted on 2023-05-28, 08:52 authored by Kehinde ObamiroKehinde Obamiro

Atrial fibrillation (AF) is the most common arrhythmia encountered in clinical practice, and is responsible for 20-30% of all strokes. AF-related strokes are more severe, and result in longer hospital stays and higher mortality compared to non-AF-related strokes. In Australia, the prevalence of AF is 5.35% in individuals aged 55 years and older, and it is associated with a cost of at least AUD$1.25 billion per year, resulting largely from the incidence of stroke, heart failure and premature mortality. Oral anticoagulant (OAC) therapy is highly effective for stroke prevention in patients with AF; however, it is also associated with the potential risk of bleeding. Evidence from clinical trials demonstrates that OAC therapy reduces the risk of stroke by 64% to 70%, and is associated with a rate of major bleeding events of up to 3.6% per year. For optimal benefit to be derived from OAC therapy, patients are required to adhere to the prescribed regimen and have sufficient knowledge regarding their medication. Various studies have demonstrated associations between suboptimal adherence and inadequate knowledge regarding OAC therapy with poor treatment outcomes. Suboptimal adherence to OAC therapy has been associated with increased risks of both bleeding and embolic events, while inadequate knowledge has been associated with poor anticoagulation control, which in turn is associated with poorer clinical outcomes. This suggests that OAC knowledge and adherence are important concepts to be considered in high quality management of patients with AF. Assessment of medication knowledge in routine clinical practice requires the use of validated psychometric instruments. The majority of studies conducted in patients with AF have utilised instruments of unknown validity to evaluate OAC knowledge. This makes it difficult to ascertain whether OAC knowledge has been appropriately assessed. In the last decade, the Anticoagulant Knowledge Assessment (AKA) by Briggs et al and the Oral Anticoagulant Knowledge test (OAK) by Zeolla et al were developed and validated to assess OAC knowledge. However, both the OAK and AKA are only able to assess knowledge related to the use of vitamin K antagonists (VKAs), and are not applicable to the direct-acting oral anticoagulants (DOACs). An instrument that caters for both patients taking VKAs and DOACs would be useful in clinical practice to identify knowledge deficit in patients with AF, and to guide subsequent educational intervention. Additionally, there is a lack of contemporary data regarding OAC knowledge level and the rate of non-adherence to OAC therapy in Australia, and their relationship with patient-related factors. Contemporary data are necessary to assess the adequacy of OAC knowledge in the population, and address any deficiencies or misconceptions. Furthermore, contemporary data are needed to identify the barriers to OAC adherence, and identify relevant predictors of non-adherence in the population. Studies related to OAC knowledge and adherence that have been conducted in Australia to date have focused primarily on participants taking VKAs (warfarin). Given the increased rate of prescription of DOACs, as well as switching of patients previously taking warfarin to DOACs, recent data on OAC therapy would be useful in evaluating the impact of DOAC prescribing on patients' knowledge level and adherence to therapy. Accordingly, the development of this thesis was guided by the Capability, Opportunity and Motivation Model of Behaviour (COM-B), which hypothesises that interaction between three components, Capability, Opportunity and Motivation (COM), influence the performance of Behaviour (B). Factors related to each of the three components were explored as they influence OAC adherence. Therefore, the overall objective of this research was to fill these gaps by developing an instrument that caters for all OACs, and assessing OAC knowledge and adherence in patients with AF. The specific aims were: ‚Äö To develop and validate a new OAC knowledge instrument that caters for both VKAs (warfarin) and the DOACs. ‚Äö To use this instrument, the Anticoagulation Knowledge Tool (AKT), to investigate the relationships between OAC knowledge, adherence and health literacy in patients with AF. ‚Äö To determine the level of OAC knowledge in patients with AF taking OAC therapy (either warfarin or a DOAC), identify any domains where significant knowledge gaps exist, and assess the association between patient-related factors and OAC knowledge. ‚Äö To estimate the proportion of patients who are non-adherent to OAC and identify predictors of adherence, and to determine if patient-related factors vary across levels of adherence in patients with AF. Due to the absence of a suitable instrument to assess OAC knowledge, we began this research by conducting a comprehensive review of the literature on anticoagulation knowledge, from which a draft instrument was developed. Ten anticoagulation experts were contacted to provide feedback on the draft instrument using a Likert scale, after which the content validity index for the instrument was calculated. For construct validity, three groups of participants comprising of 44 pharmacists, 50 patients and 50 members of the general public were tested using the instrument developed, and the results of these three cohorts were compared. Reliability analyses were conducted to determine if included items were measuring the same general construct, and if the instrument could provide consistent results. A subgroup of participants in the patient and pharmacist groups were re-tested approximately 2‚Äö-3 months after the initial testing to assess test retest reliability using Pearson's correlation coefficient, while internal consistency reliability was assessed by calculating a Cronbach's ˜í¬± value for the three groups. The final 28-item instrument, called the AKT, has a scale content validity index of 0.92, supporting content validity. The pharmacist group's mean score (94%) was significantly higher than that of the patient group (62%), and the patient group scored significantly higher than the general public group (20%) (p <0.001), supporting construct validity. Internal consistency reliability was acceptable with a Cronbach's ˜í¬± value of >0.7 across the three groups, and test-retest reliability was confirmed with a Pearson's correlation coefficient of 0.72 and 0.78 for the pharmacist and patient groups, respectively. After the development of the AKT, the instrument was piloted in a study involving 48 patients designed to investigate the relationships between OAC knowledge, adherence and health literacy in patients with AF. Participants were recruited from general practices for a face-to-face interview using the AKT to assess OAC knowledge; the Morisky Medication Adherence Scale (MMAS-8) to assess adherence; and the Short Test of Functional Health Literacy in Adults (s-TOFHLA) to assess health literacy. Participants had mean scores of 61.6 ¬¨¬± 15.8, 7.2 ¬¨¬± 1.1 and 24.7 ¬¨¬± 9.5 for the AKT, MMAS-8 and s-TOFHLA, respectively. Significant correlations were observed between OAC knowledge and health literacy with medication adherence (0.37, p = 0.009 and 0.30, p = 0.042, respectively), and between OAC knowledge and health literacy (0.31, p = 0.033). Participants with inadequate health literacy had a significantly lower mean knowledge score than those with adequate health literacy (55.8 ¬¨¬± 15.9 versus 66.1 ¬¨¬± 14.4, p = 0.022). In addition, participants who reported adequate adherence to OAC therapy had significantly higher knowledge scores than those who did not (67.5 ¬¨¬± 13.3 versus 56.1 ¬¨¬± 16.2, p = 0.011). After confirming the usability and adequacy of the AKT, the next phase of this research focused on assessing OAC knowledge and adherence in patients with AF in a nationally representative sample of patients with AF. The study was designed as an online survey to improve reachability and ensure better representation. Survey components used included the AKT, the Perception of Anticoagulant Treatment Questionnaires (assessing treatment expectations, convenience and satisfaction), a modified Cancer Information Overload scale to assess perception of information overload, and the MMAS-8 to assess OAC adherence. Although participants taking warfarin had a higher knowledge score compared to those taking DOACs (n = 386, 73.4 ¬¨¬± 13.2 versus 65.7 ¬¨¬± 13.7, p <0.001), knowledge gaps were generally observed in key areas of self-management including the following: missing a dose, drug interactions and recognising bleeding as an important side effect. Patient-related factors including age in years (p = 0.009) and perception of information overload (p <.001) were significant predictors of knowledge. To estimate the proportion of patients who were non-adherent to OAC therapy, and identify factors associated with adherence in the population, a secondary analysis of the data was conducted. Nonadherence to OAC therapy was common, as only 54.9% of participants reported a high adherence to OAC. Participants aged ‚Äöv¢¬ß65 years were less likely to have high adherence compared to older participants (OR, 0.54; 95% CI, 0.33 ‚Äö- 0.88; p = 0.013), while females were more likely to be highly adherent compared to males (OR, 1.69; 95% CI, 1.08 ‚Äö- 2.64; p = 0.023). Moreover, the result of the secondary analysis showed that treatment satisfaction (p <0.001) and perception of information overload (p <0.001) varied across adherence levels. Mapping the results from this research to the COM-B framework suggests that each of the components could be explored to improve OAC adherence. Improving knowledge and health literacy levels may increase patients' psychological capability to engage in the necessary thought process that would encourage adherence to OACs. Potentially, healthcare practitioners could use the results of this research to help shape patients' perception and beliefs concerning OAC th...


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Copyright 2018 the author Chapter 2 appears to be the equivalent of a post-peer-review, pre-copyedit version of an article published in American journal of cardiovascular drugs. The final authenticated version is available online at: Chapter 3 appears to be the equivalent of a post-print version of an article published as: Obamiro, K. O., Chalmers, L., Bereznicki, L. R. E., 2016. Development and validation of an oral anticoagulation knowledge tool (AKT). PLoS ONE 11(6), e0158071. Copyright: Copyright 2016 Obamiro et al. It is an open access article distributed under the terms of the Creative Commons Attribution 4.0 International (CC BY 4.0) License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Chapter 4 appears to be the equivalent of the pre-peer reviewed version of the following article: Rolls, C. A., Obamiro, K. O., Chalmers, L., Bereznicki, L. R. E., 2017. The relationship between knowledge, health literacy, and adherence among patients taking oral anticoagulants for stroke thromboprophylaxis in atrial fibrillation. Cardiovascular therapeutics, 35(6), 1-8, e12304, which has been published in final form at This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions. Chapter 5 appears to be the equivalent of the pre-peer reviewed version of the following article: Obamiro, K.O., Chalmers, L., Lee, K., Bereznicki, B. J., Bereznicki, L. R.E., Anticoagulation knowledge in patients with atrial fibrillation: An Australian survey. International journal of clinical practice, 72(3), e13072 which has been published in final form at This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions. Chapter 6 appears to be the equivalent of a post-print version of an article published as: Obamiro, K. O., Chalmers, L., Lee, K., Bereznicki, B. J., Bereznicki, L. R., 2018. Adherence to oral anticoagulants in atrial fibrillation: an Australian survey, Journal of cardiovascular pharmacology and therapeutics, 23(4), 337‚Äö-343

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How do we decide which patients with atrial fibrillation should be on anticoagulation? ›

INTRODUCTION — Most patients with atrial fibrillation (AF) should receive long-term oral anticoagulation to decrease the risk of ischemic stroke and other embolic events. For most patients, the benefit from anticoagulation outweighs the associated increase in the risk of bleeding.

How do you monitor anticoagulation therapy? ›

The level of anticoagulation may be monitored with the APTTActivated partial thromboplastin time and/or Anti factor Xa level, however monitoring(including the test and frequency) should be according to local guidelines. Prophylactic (low dose) heparin does not usually require monitoring.

What is the anticoagulation knowledge tool AKT? ›

The Anticoagulation Knowledge Tool (AKT) was developed to assess OAC knowledge and caters for both patients prescribed direct oral anticoagulants or vitamin K antagonist (VKA).

When should I start anticoagulation after atrial fibrillation? ›

For patients with a moderate clinical stroke/moderate-sized infarct on imaging (without hemorrhage on CT), anticoagulation may be started 6-7 days post-stroke. d. For patients with a severe clinical stroke/large-sized infarct on imaging (without hemorrhage on CT), anticoagulation may be started 12-14 days post-stroke.

What is the standard of care for atrial fibrillation? ›

Key Recommendations. Rate control is recommended in preference to rhythm control for the majority of patients who have atrial fibrillation. Preferred options for rate control therapy include non-dihydropyridine calcium channel blockers and beta blockers.

Why not give anticoagulants for atrial fibrillation? ›

Increasingly common factors such as previous bleeding, frailty, and an overall high bleeding risk are amongst the most frequently reported reasons for withholding anticoagulation.

What should you assess before giving anticoagulants? ›

Conduct thorough physical assessment before beginning drug therapy to establish baseline status, determine effectivity of therapy, and evaluate potential adverse effects. Obtain baseline status for complete blood count, fecal occult blood test (FOBT), and clotting studies to determine any potential adverse effects.

What should a client receiving anticoagulant be monitored for? ›

Once target anticoagulation is achieved, anticoagulation labs are monitored once daily. Patients on anticoagulant therapy must be educated about their increased risk for bleeding, monitoring for bleeding, managing bleeding if it occurs, and drug-specific information.

What is the patient teaching for anticoagulant therapy? ›

Take your anticoagulant at the same time every day, as directed by your doctor or nurse. This is important because it makes the medication work more effectively. If you miss or skip a dose, contact your doctor or clinic. Do not take a double dose.

What is the primary goal of anticoagulant therapy? ›

Anticoagulants are the mainstay of therapy for the acute and long-term prevention and treatment of numerous types of thromboembolic disorders. The prevention of thromboembolic stroke among patients with chronic atrial fibrillation (AF) is one of the primary indications for oral anticoagulation therapy.

Which clinical scoring tool can be used to help determine the potential safety of anticoagulation use? ›

Using the HAS-BLED score

A high score identifies patients who may be at high risk of bleeding, as well as potentially modifiable bleeding risk factors.

Which of these tests is used to monitor anticoagulant therapy? ›

The prothrombin time (PT) is a test that helps evaluate your ability to appropriately form blood clots. The international normalized ratio or INR is a calculation based on results of a PT that is used to monitor individuals who are being treated with the blood-thinning medication (anticoagulant) warfarin (Coumadin®).

What is the best blood thinner for atrial fibrillation? ›

For many years, warfarin was the first-choice blood thinner to prevent stroke in people with AFib. But a newer group of medications called direct oral anticoagulants (DOACs) are now considered the best blood thinners for AFib treatment. DOACs include Pradaxa, Xarelto, and Eliquis.

Why does atrial fibrillation cause blood clots? ›

AFib interferes with the flow of blood through your heart. This can cause blood to pool in your heart's upper chambers, which can cause blood clots to form.

What do you monitor a patient with atrial fibrillation? ›

  • Electrocardiogram (ECG or EKG). This quick and painless test measures the electrical activity of the heart. ...
  • Blood tests. These help a doctor rule out thyroid problems or detect other substances in the blood that may lead to A-fib .
  • Holter monitor. ...
  • Event recorder. ...
  • Echocardiogram. ...
  • Stress test. ...
  • Chest X-ray.
Oct 19, 2021

What are the main goals in treatment for atrial fibrillation? ›

Atrial fibrillation is treated with lifestyle changes, medicines, and procedures, including surgery, to help prevent blood clots, slow your heartbeat, or restore your heart's normal rhythm.

What is the main intervention used for atrial fibrillation treatment? ›

Cardioversion. Cardioversion may be recommended for some people with atrial fibrillation. It involves giving the heart a controlled electric shock to try to restore a normal rhythm. Cardioversion is usually carried out in hospital so the heart can be carefully monitored.

What is the first line of rhythm control for atrial fibrillation? ›

Beta-blockers and calcium channel blockers are first-line agents for rate control in AF. These drugs can be administered either intravenously or orally. They are effective at rest and with exertion. Intravenous diltiazem or metoprolol are commonly used for AF with a rapid ventricular response.

Does everyone with atrial fibrillation need blood thinners? ›

Research suggests that about 10 percent of AFib patients don't need blood thinners because their risk of having a stroke is so low. National data also suggests that an additional 20 percent of AFib patients are not taking a blood thinner when they should be.

Do people with AFib take anticoagulants? ›

If you have atrial fibrillation (AFib), your doctor may suggest long-term blood thinners, also called anticoagulants. They lower your risk for stroke caused by a blood clot, the most dangerous complication of AFib. Your doctor will use a formula to find out how high your risk of stroke is.

What is the nurse's responsibility in anticoagulant therapy? ›

The nurse must maintain constant vigilance of patients receiving anticoagulant therapy. She should become skilled in observing for signs and symptoms of bleeding. Equally important is the nurse's ability to gain the cooperation of the patient and to teach him how to care for and protect himself.

What is the role of the nurse in administering anticoagulants? ›

Before a patient commences an anticoagulation drug, the nurse should decide whether this is appropriate through careful consideration of the thrombosis and bleeding risks. For example, before anticoagulation drugs are administered for AF, a patient's risk of stroke and bleeding should be assessed.

What does a nurse do at an anticoagulation clinic? ›

Interprets INR and adjusts warfarin dosing, using practice guidelines and clinical judgment for each patient. Assesses for signs and symptoms of bleeding, thromboembolism and appropriately refers to physician. Identifies, triages or manages other medical problems through the appropriate health care provider.

What symptoms should a patient report when on anticoagulant therapy? ›

Signs of internal bleeding include severe headache or changes in strength in one part of the body, blood in the urine, bloody or dark stool, or vomiting blood. These signs should prompt immediate discussion with your healthcare provider, who may order a PT/INR test and an in-person evaluation.

What is the nurse's priority assessment for a patient receiving heparin treatment? ›

Rationale: When caring for a client who is receiving heparin, the nurse should monitor the aPTT to evaluate medication effectiveness. The aPTT evaluates the intrinsic and final common pathways of the coagulation cascade that are affected by heparin.

Should all AFib patients be on blood thinners? ›

If you have atrial fibrillation (AFib), your doctor may suggest long-term blood thinners, also called anticoagulants. They lower your risk for stroke caused by a blood clot, the most dangerous complication of AFib. Your doctor will use a formula to find out how high your risk of stroke is.

What is the 1 3 6 12 rule? ›

This '1–3–6–12' day rule states OAC would be started on day 1 following a transient ischaemic attack (TIA), day 3 following a mild stroke, day 6 following a moderate stroke and on day 12 following severe stroke.

What is the 1 3 6 12 day rule? ›

The 1-3-6-12-day rule is a known consensus with graded increase in delay of anticoagulation between 1 and 12 days after onset of ischemic stroke or transient ischemic attack (TIA), according to neurological severity based on European expert opinions.

Which risk calculator is utilized in clinical decision making for anticoagulation therapy with atrial fibrillation? ›

The GARFIELD-AF risk calculator was designed to help clinicians assess the future risk of mortality, ischaemic stroke and major bleeding (including haemorrhagic stroke), as a guide to using anticoagulants in patients with a new diagnosis of atrial fibrillation (AF).

What is the biggest concern with AFib? ›

Atrial fibrillation (A-fib) is an irregular and often very rapid heart rhythm (arrhythmia) that can lead to blood clots in the heart. A-fib increases the risk of stroke, heart failure and other heart-related complications.

What is the most important risk factor for AFib? ›

The risk for AFib increases with age. High blood pressure, the risk for which also increases with advancing age, accounts for about 1 in 5 cases of AFib.

What anticoagulants are used in atrial fibrillation? ›

Non-vitamin K oral anticoagulants (NOACs) are direct thrombin (dabigatran) or factor Xa (rivaroxaban, apixaban, edoxaban) inhibitors.

What is the rule of the following sequence 1 2 4 7 12 20 33? ›

1, 2, 4, 7, 12, 20, 33, 54, 88, ... with offset 1. This sequence counts the number of Fibonacci meanders. A Fibonacci meander is a meander which does not change direction to the left except at the beginning of the curve where it is allowed to make (or not to make) as many left turns as it likes.

What is the 6 12 6 rule? ›

The primary rule is what's known as the 6'/12′ rule. NEC 210-52 states the following (abbreviated for easier digestion): Receptacles are needed in every room of a home such that no point on a wall is over 6′ from an outlet. This means that you need an outlet within 6′ of a doorway or fireplace.

What is the 6 12 12 rule? ›

The NEC basically states that within any living area of a home, you must have an electrical receptacle (outlet) 6 feet from any obstruction or break in the wall, such as a doorway, and no more than 12 feet from the previous electrical receptacle (outlet), Figure 1.

What is optimal INR for atrial fibrillation? ›

For patients with AF or atrial flutter and moderate-to-severe mitral stenosis regardless CHA2DS2-VASc score anticoagulation with warfarin (INR 2.0-3.0), is recommended.


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