ARCHIVED All Wales Advice on the Role of Oral Anticoagulants for the Prevention of Stroke and Systemic Embolism in People with Atrial Fibrillation

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1 ARCHIVED All Wales Advice on the Role of Oral Anticoagulants for the Prevention of Stroke and Systemic Embolism in People with Atrial Fibrillation THESE RECOMMENDATIONS HAVE BEEN SUPERSEDED. PLEASE CLICK HERE FOR CURRENT RECOMMENDATIONS. October 2012

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3 All Wales Advice on the Role of Oral Anticoagulants for the Prevention of Stroke and Systemic Embolism in People with Atrial Fibrillation CONTENTS BACKGROUND 4 AWMSG STATEMENTS INITIAL ASSESSMENT CHOICE OF ANTICOAGULANT PRESCRIBING RESPONSIBILITY LEVEL OF INR CONTROL ADDITIONAL CONSIDERATIONS 18 References 19 Appendix 1 21 Appendix 2 22 This document should be cited as: All Wales Medicines Strategy Group. All Wales advice on the role of oral anticoagulants for the prevention of stroke and systemic embolism in people with atrial fibrillation. October

4 All Wales Medicines Strategy Group BACKGROUND In March 2012 and May 2012, the National Institute for Health and Clinical Excellence (NICE) published technology appraisals (TA) 249 and 256, which recommended dabigatran etexilate (Pradaxa ) and rivaroxaban (Xarelto ), respectively, as treatment options for the prevention of stroke and systemic embolism in atrial fibrillation (see Table 1) 1,2. Many health boards in Wales have subsequently developed comprehensive guidance regarding the use of dabigatran etexilate. Less health board guidance is currently available for rivaroxaban. A multiprofessional collaborative group was established to consider the variations in existing guidance and to promote the safe, effective and equitable use of oral anticoagulant therapies. The following statements have been developed by the All Wales Medicines Strategy Group (AWMSG) to support the interpretation and implementation of NICE TA249 and TA256 1,2 (see Table 1); the AWMSG statements are linked to this guidance and to each other, and therefore should not be quoted separately. This document relates to warfarin, dabigatran etexilate and rivaroxaban for the indication of prevention of stroke and systemic embolism in people with atrial fibrillation; it does not consider any other indications. AWMSG STATEMENTS 1.0 INITIAL ASSESSMENT All clinicians considering the initiation of oral anticoagulants should: document a risk assessment (including renal function); 1.1 document the discussion between the clinician and the person about the risks and benefits of treatment, using accredited decision aids where possible. The focus of atrial fibrillation management should be to identify affected people and undertake stroke risk assessment using the CHADS 2, or 1.2 the more recently introduced CHA 2 DS 2 -VASc, risk assessment tool. 1.3 Assessment of bleeding risk should be carried out using an appropriate tool, such as HAS-BLED. For people with a CHADS 2 score 2, chronic oral anticoagulation therapy is recommended, unless contraindicated. People with a CHADS 2 score < 2 require further assessment, and the CHA 2 DS 2 -VASc risk assessment tool can aid the decision. 4

5 All Wales Advice on the Role of Oral Anticoagulants for the Prevention of Stroke and Systemic Embolism in People with Atrial Fibrillation 2.0 CHOICE OF ANTICOAGULANT Use of warfarin first line* for most people will support the managed entry of the newer agents For some individuals, it may be necessary to consider an alternative agent after an informed discussion between the clinician and the person. This recommendation will be reviewed in 12 months. If a person is unable to achieve an INR within the target therapeutic range whilst taking warfarin (see Section 4.0. Level of INR control), dabigatran etexilate /rivaroxaban may be considered as an alternative. Evidence suggests that warfarin is not an effective intervention when time in therapeutic range is less than 58% 3,4. (See Statement 2.4 on medicines adherence.) The decision about whether to start treatment with dabigatran etexilate /rivaroxaban should be made after an informed discussion between the clinician and the person about the risks and benefits of dabigatran etexilate /rivaroxaban compared with warfarin, per NICE TA249 and TA256 1,2. People in whom adherence to medicines is known to be an issue may not be suitable for dabigatran etexilate /rivaroxaban. Poor adherence to any oral anticoagulant regimen is likely to be associated with increased risk of thrombosis or bleeding. The prescriber should make efforts to understand and address the reasons for non-adherence before switching to an alternative medicine. 3.0 PRESCRIBING RESPONSIBILITY Should initiation of the new oral anticoagulants be restricted to specific groups of prescribers? For people with a new diagnosis of atrial fibrillation, the decision to initiate dabigatran etexilate /rivaroxaban should be on the advice of secondary care clinicians with an interest in stroke prevention and management of atrial fibrillation. For people with existing atrial fibrillation, the decision to switch from current therapy to dabigatran etexilate /rivaroxaban for this indication should be carried out by clinicians with an interest in stroke prevention and management of atrial fibrillation. It may be appropriate for GP practices that provide level 3 and 4 anticoagulation services to make the decision to switch to dabigatran etexilate /rivaroxaban, depending on health board service models. 5

6 All Wales Medicines Strategy Group 4.0 LEVEL OF INR CONTROL Where warfarin is prescribed, time in therapeutic range should not be 4.1 assessed within the initiation period (normally 1 3 months). A monitoring period of six months (after the initiation period) would give 4.2 a good indication of time in therapeutic range. 4.3 Ability to measure time in therapeutic range is advised 5. Unexplained, recurrent extreme INR variation is a useful alternative marker of INR control in addition to time in therapeutic range. 4.4 If prescribers identify extreme INRs, medicines adherence should be considered, as outlined in Statement ADDITIONAL CONSIDERATIONS 5.1 All suspected adverse reactions to dabigatran etexilate /rivaroxaban should be reported directly to the MHRA through the Yellow Card Scheme using the electronic form at or the cards available at the back of the BNF. * Use of the term first line relates to the preferred treatment option, but does not preclude the use of other agents where appropriate. AWMSG advice does not affect the clinical freedom of the prescriber. Table 1. NICE TA249 and TA256 recommendations 1,2 NICE TA249: Dabigatran etexilate for the prevention of stroke and systemic embolism in atrial fibrillation 1.1 Dabigatran etexilate is recommended as an option for the prevention of stroke and systemic embolism within its licensed indication, that is, in people with nonvalvular atrial fibrillation with one or more of the following risk factors: previous stroke, transient ischaemic attack or systemic embolism left ventricular ejection fraction below 40% symptomatic heart failure of New York Heart Association (NYHA) class 2 or above age 75 years or older age 65 years or older with one of the following: diabetes mellitus, coronary artery disease or hypertension. NICE TA256: Rivaroxaban for the prevention of stroke and systemic embolism in people with atrial fibrillation 1.1 Rivaroxaban is recommended as an option for the prevention of stroke and systemic embolism within its licensed indication, that is, in people with nonvalvular atrial fibrillation with one or more risk factors such as: congestive heart failure hypertension age 75 years or older diabetes mellitus prior stroke or transient ischaemic attack. 1.2 The decision about whether to start treatment with dabigatran etexilate/rivaroxaban should be made after an informed discussion between the clinician and the person about the risks and benefits of dabigatran etexilate/rivaroxaban compared with warfarin. For people who are taking warfarin, the potential risks and benefits of switching to dabigatran etexilate/rivaroxaban should be considered in light of their level of international normalised ratio (INR) control. 6

7 All Wales Advice on the Role of Oral Anticoagulants for the Prevention of Stroke and Systemic Embolism in People with Atrial Fibrillation 1.0 INITIAL ASSESSMENT 1.1 All clinicians considering the initiation of oral anticoagulants should: document a risk assessment (including renal function); document the discussion between the clinician and the person about the risks and benefits of treatment, using accredited decision aids where possible. 1.2 The focus of atrial fibrillation management should be to identify affected people and undertake stroke risk assessment using the CHADS 2, or the more recently introduced CHA 2 DS 2 -VASc, risk assessment tool. Assessment of bleeding risk should also be carried out using an appropriate tool, such as HAS-BLED. 1.3 For people with a CHADS 2 score 2, chronic oral anticoagulation therapy is recommended, unless contraindicated. People with a CHADS 2 score < 2 require further assessment, and the CHA 2 DS 2 -VASc risk assessment tool can aid the decision. Where a diagnosis of atrial fibrillation has been established (permanent or paroxysmal), a risk benefit assessment should be performed and options discussed with the patient to inform the decision of whether or not to prescribe antithrombotic therapy. Table 2. CHADS 2 scoring system Risk factor Score None 0 C Heart failure 1 H Hypertension 1 A Age 75 1 D Diabetes mellitus 1 S 2 Stroke/transient ischaemic attack 2 Table 3. CHA 2 DS 2 -VASc scoring system Risk factor Score None 0 C Heart failure/lv dysfunction 1 H Hypertension 1 A 2 Age 75 2 D Diabetes mellitus 1 S 2 Stroke/transient ischaemic attack/thromboembolism 2 V Vascular disease 1 A Age Sc Female 1 7

8 All Wales Medicines Strategy Group The CHADS 2 scoring system was previously recommended as the primary stroke risk stratification tool 6. The 2010 European Society of Cardiology (ESC) guidelines for the management of atrial fibrillation stated: The CHADS 2 stroke risk stratification scheme should be used as a simple initial (and easily remembered) means of assessing stroke risk, particularly suited to primary care doctors and non-specialists. In patients with a CHADS 2 score of 2, chronic OAC [oral anticoagulant] therapy, e.g. with a VKA [vitamin k antagonist], is recommended in a dose adjusted [approach] to achieve an INR value in the range of , unless contraindicated. 6 The advice to consider chronic oral anticoagulation therapy for patients with a CHADS 2 score 2 is consistent with the RE-LY and ROCKET-AF study populations (see Section 2.2). NICE TA256 notes that the population in the study comparing dabigatran etexilate with warfarin (RE-LY) had a lower risk of stroke (mean CHADS 2 score 2.1) than the population in the ROCKET-AF trial (mean CHADS 2 score of 3.47) 2. An inclusion criterion of the ROCKET-AF trial was a baseline CHADS 2 score of 2 7. CHA 2 DS 2 -VASc is increasingly recognised as an alternative assessment tool. Guidance from several health boards in Wales refer to the use of the CHADS 2 or CHA 2 DS 2 -VASc scoring systems, setting a score 2 for both as the point of initiation of chronic oral anticoagulation. It has been found that, compared with CHADS 2, CHA 2 DS 2 -VASc redistributes many patients, particularly older women, from the low- to high-risk categories 8. With regards to the CHA 2 DS 2 -VASc scoring system, the recently updated ESC guidelines for the management of atrial fibrillation (2012) state: The CHA 2 DS 2 -VASc score is recommended as a means of assessing stroke risk in non-valvular AF. In patients with a CHA 2 DS 2 -VASc score of 0 (i.e., aged < 65 years with lone AF) who are at low risk, with none of the risk factors, no antithrombotic therapy is recommended. In patients with a CHA 2 DS 2 -VASc score 2, OAC therapy [...] is recommended unless contraindicated. 9 This approach will increase the number of patients that are recommended oral anticoagulants, and should be considered in the context of the following: there remain concerns over the applicability of data for the [new oral anticoagulants] to very elderly patients with multiple comorbidities, polypharmacy, compliance issues etc., who are often managed by primary care physicians. 9 8

9 All Wales Advice on the Role of Oral Anticoagulants for the Prevention of Stroke and Systemic Embolism in People with Atrial Fibrillation Anderson et al (2012) suggest that using the CHA 2 DS 2 -VASc scoring system instead of CHADS 2 widens the indication for oral anticoagulant prophylactic therapy of atrial fibrillation: Overall, 56.3% and 85.1% of the population were at high risk of stroke ( 2 points) according to CHADS 2 and CHA 2 DS 2 -VASc, respectively. In addition, 26.9% had an increased bleeding risk according to HAS-BLED. 10 Table 4. CHADS 2 score and adjusted stroke rate 6,11 Adjusted stroke rate CHADS 2 score (% per year) Table 5. CHA 2 DS 2 -VASc score and adjusted stroke rate 6,12 Adjusted stroke rate CHA 2 DS 2 -VASc score (% per year) The CHADS 2 measure was introduced into the Quality and Outcomes Framework (QoF) in : AF5. The percentage of patients with atrial fibrillation in whom stroke risk has been assessed using the CHADS 2 risk stratification scoring system in the preceding 15 months (excluding those whose previous CHADS 2 score is greater than 1). AF6. In those patients with atrial fibrillation in whom there is a record of a CHADS 2 score of 1 (latest in the preceding 15 months), the percentage of patients who are currently treated with anti-coagulation drug therapy or antiplatelet therapy 9

10 All Wales Medicines Strategy Group AF7. In those patients with atrial fibrillation whose latest record of a CHADS 2 score is greater than 1, the percentage of patients who are currently treated with anti-coagulation therapy. 13 The predicted risk of thrombotic stroke must be considered in the context of an assessment of bleeding risk. The AWMSG guidance document Warfarin Monitoring includes a comprehensive risk assessment designed to highlight patients who may be at increased risk of bleeding and complications associated with warfarin use 14. This highlights concerns such as memory loss and falls but does not provide a score, unlike HAS-BLED (see Table 6). Some GP software systems include calculators for CHADS 2, and a smaller proportion also include CHA 2 DS 2 -VASc risk assessment tools. HAS-BLED is not currently incorporated. According to the 2012 ESC guidelines for the management of atrial fibrillation: A formal bleeding risk assessment is recommended for all patients with AF, and in patients with a HAS-BLED score 3, caution and regular review are appropriate, as well as efforts to correct the potentially reversible risk factors for bleeding. The HAS-BLED score per se should not be used to exclude patients from OAC therapy but allows clinicians to make an informed assessment of bleeding risk. 9 Example of good practice The collaborative group supported the completion of a pro forma for each patient for whom oral anticoagulation therapy is being considered in order to promote the safe and effective use of medication. Cardiff and Vale University Health Board has developed a summary sheet Atrial Fibrillation: stroke risk assessment and antithrombotic treatment recommendation 15, which includes the following: Patient details Consultant Directorate Date CHADS 2 score; CHA 2 DS 2 -VASc score if CHADS 2 score < 2 HAS-BLED score Renal function Patient consent Documented discussion of risks and benefits Choice of antithrombotic medication Identification of relevant criteria within licensed indication Doctor s details Signature of doctor Authorising consultant Date of signing 10

11 All Wales Advice on the Role of Oral Anticoagulants for the Prevention of Stroke and Systemic Embolism in People with Atrial Fibrillation Table 6. Clinical characteristics comprising the HAS-BLED bleeding risk score, as defined in ESC guidelines for the management of atrial fibrillation 6 Letter Clinical characteristic* Points awarded H Hypertension 1 A Abnormal renal and liver function (1 point each) 1 or 2 S Stroke 1 B Bleeding 1 L Labile INRs 1 E Elderly (e.g. age > 65 years) 1 D Drugs or alcohol (1 point each) 1 or 2 Maximum 9 points *Hypertension is defined as systolic blood pressure > 160 mmhg. Abnormal kidney function is defined as the presence of chronic dialysis or renal transplantation or serum creatinine 200 micromoles/l. Abnormal liver function is defined as chronic hepatic disease (e.g. cirrhosis) or biochemical evidence of significant hepatic derangement (e.g. bilirubin more than twice upper limit of normal, in association with aspartate aminotransferase/alanine aminotransferase/alkaline phosphatase more than three times upper limit normal, etc.). Bleeding refers to previous bleeding history and/or predisposition to bleeding, e.g. bleeding diathesis, anaemia, etc. Labile INRs refers to unstable/high INRs or poor time in therapeutic range (e.g. < 60%). Drugs/alcohol use refers to concomitant use of drugs, such as antiplatelet agents, non-steroidal anti-inflammatory drugs, or alcohol abuse, etc. INR: international normalised ratio. 11

12 All Wales Medicines Strategy Group 2.0 CHOICE OF ANTICOAGULANT Since the introduction of the new oral anticoagulants, NICE has not specified a particular anticoagulant of choice. TA249 and TA256 make the following statements: Dabigatran etexilate is recommended as an option for the prevention of stroke and systemic embolism within its licensed indication 1. Rivaroxaban is recommended as an option for the prevention of stroke and systemic embolism within its licensed indication 2. Whilst recognising the financial constraints of the NHS, the focus of this guidance is on safety. The long-term safety and efficacy of both dabigatran etexilate and rivaroxaban in large populations involving complex elderly patients are yet to be determined, and the lack of readily available antidotes should be noted. The availability of antidotes will alter the balance of risk and benefit considerably. 2.1 Use of warfarin first line* for most people will support the managed entry of the newer agents. For some individuals, it may be necessary to consider an alternative agent after an informed discussion between the clinician and the person. This recommendation will be reviewed in 12 months *Use of the term first line relates to the preferred treatment option, but does not preclude the use of other agents where appropriate. AWMSG advice does not affect the clinical freedom of the prescriber for individual patients. Patients with atrial fibrillation at risk of stroke that are currently well controlled on warfarin should remain on warfarin. Patient factors such as the ability to manage dose changes and attend INR monitoring should be considered. 2.2 If a person is unable to achieve an INR within the target therapeutic range whilst taking warfarin (see Section 4.0. Level of INR control), dabigatran etexilate /rivaroxaban may be considered as an alternative. Evidence suggests that warfarin is not an effective intervention when time in therapeutic range is less than 58% 3,4. (See Statement 2.4 on medicines adherence.) NICE TA249 and TA256 state: For people who are taking warfarin, the potential risks and benefits of switching to [dabigatran etexilate/rivaroxaban] should be considered in light of their level of international normalised ratio (INR) control. 1,2 In undertaking appraisals TA249 and TA256, evidence from two pivotal trials was considered by the respective NICE Evidence Review Groups (ERGs) 1,2 : RE-LY and ROCKET-AF were randomised, non-inferiority trials of dabigatran etexilate and rivaroxaban, respectively, versus warfarin in patients with atrial fibrillation and at risk of stroke 7,16. 12

13 All Wales Advice on the Role of Oral Anticoagulants for the Prevention of Stroke and Systemic Embolism in People with Atrial Fibrillation The NICE ERG for TA249 noted that, based on an analysis in the submission produced for the Food and Drug Administration (FDA): the greatest benefit of dabigatran was in the lowest quartile of INR control and that, in people with good INR control with warfarin, little or no additional benefit in terms of effectiveness would be gained with dabigatran 1. The endpoints of RE-LY were subdivided by INR control into four groups (time in therapeutic range < 58.5%, > 58.5%, < 66.8%, > 66.8% and < 74.2%) 3 ; the published paper suggests that the lowest level of time in therapeutic range for which warfarin shows benefit in reducing stroke in atrial fibrillation patients is 58% 4. The NICE ERG for TA256 noted that in the ROCKET-AF trial, the mean time in therapeutic range for the INR range of for warfarin was 55%. The time in therapeutic range achieved within the Western European population in the study was 60.62% The decision about whether to start treatment with dabigatran etexilate /rivaroxaban should be made after an informed discussion between the clinician and the person about the risks and benefits of dabigatran etexilate / rivaroxaban compared with warfarin, per NICE TA249 and TA256 1,2. NICE TA249 and TA256 state: The decision about whether to start treatment with [dabigatran etexilate/rivaroxaban] should be made after an informed discussion between the clinician and the person about the risks and benefits of rivaroxaban compared with warfarin. 1,2 The Health Improvement Scotland document Prevention of stroke and systemic embolism in adult patients with non-valvular atrial fibrillation (2012) 17 summarises the potential advantages and disadvantages of dabigatran etexilate and rivaroxaban compared to warfarin for stroke prevention in non-valvular atrial fibrillation (see Appendix 1). The Summary of Product Characteristics (SPC) for dabigatran etexilate states that the half-life is approximately 13 hours with normal renal function, increasing to 27 hours if creatinine clearance rate is < 30 ml/min. Clearance of dabigatran etexilate by haemodialysis was investigated in seven patients with end-stage renal disease without atrial fibrillation, and this resulted in a removal of 50 60% of dabigatran etexilate concentrations 18. The SPC for rivaroxaban states that it has a half-life of approximately 5 13 hours 19. Due to the high plasma protein binding, rivaroxaban is not expected to be dialysable. 2.4 People in whom adherence to medicines is known to be an issue may not be suitable for dabigatran etexilate /rivaroxaban. Poor adherence to any oral anticoagulant regimen is likely to be associated with increased risk of thrombosis or bleeding. The prescriber should make efforts to understand and address the reasons for non-adherence before switching to an alternative medicine. 13

14 All Wales Medicines Strategy Group NICE CG76 (Medicines adherence) states: It is thought that between a third and a half of all medicines prescribed for long-term conditions are not taken as recommended. If the prescription is appropriate, then this may represent a loss to patients, the healthcare system and society. The costs are both personal and economic. Non-adherence should not be seen as the patient s problem. It represents a fundamental limitation in the delivery of healthcare, often because of a failure to fully agree the prescription in the first place or to identify and provide the support that patients need later on. 20 A number of terms, eg compliance or concordance, are often used interchangeably to mean adherence. A recent article on the taxonomy for describing and defining adherence to medications states: Currently a number of terms, e.g. compliance, adherence, persistence, and concordance, are used to define different aspects of the act of seeking medical attention, acquiring prescriptions and taking medicines appropriately. These terms are often used interchangeably, but they impose different views about the relationship between the patient and the health care professional. Compliance, for instance, has been viewed by many as having the negative connotation that patients are subservient to prescribers. The term concordance, introduced originally to describe the patient prescriber relationship, is sometimes incorrectly used as a synonym for compliance. [...] These matters lead to confusion and misunderstanding, and impede comparisons of results of scientific research and implementation in practice. 21 The article provides the following definition for adherence to medication: Adherence to medications: the process by which patients take their medications as prescribed. Adherence has three components: initiation, implementation and discontinuation. 21 Rivaroxaban can be used in compliance aids. 14

15 All Wales Advice on the Role of Oral Anticoagulants for the Prevention of Stroke and Systemic Embolism in People with Atrial Fibrillation 3.0 PRESCRIBING RESPONSIBILITY Should initiation of the new oral anticoagulants be restricted to specific groups of prescribers? There is significant regional variation in the current place of initiation of warfarin in Wales. A systematic assessment of the issues of prescribing responsibility for dabigatran etexilate and rivaroxaban are outlined in Appendix For people with a new diagnosis of atrial fibrillation, the decision to initiate dabigatran etexilate /rivaroxaban should be on the advice of secondary care clinicians with an interest in stroke prevention and management of atrial fibrillation. When considering the safety of oral anticoagulants, the ability to identify people most likely to benefit and those at most risk of bleeding is essential. To ensure the safe and appropriate use of dabigatran etexilate and rivaroxaban, initiation should be managed by a clinician who has sufficient experience and confidence in the therapeutic options. This should not preclude primary care prescribing. Where there is a recommendation for initiation on the advice of secondary care clinician, there is no requirement for the first prescription to be issued by specialist. The collaborative group considered that Statement 3.2 will increase the opportunity for specialists to gain experience with the newer agents. Hospital assessment of people with new onset atrial fibrillation is not a QoF requirement. Warfarin-dosing practices (level 3 and 4) will have good understanding of patients levels of INR control; however, there will be varying confidence and competence in the use of the antithrombotic therapeutic options. It is recognised that many clinicians are unfamiliar with the new oral anticoagulants, and there is therefore a training requirement, whether initiating or undertaking ongoing prescribing. Restricting the place of initiation must be based primarily on clinical not financial grounds. It may be appropriate for GP practices that provide level 3 and 4 anticoagulation services to make the decision to initiate dabigatran etexilate or rivaroxaban, depending on health board anticoagulation service delivery models and atrial fibrillation care pathways. 3.2 For people with existing atrial fibrillation, the decision to switch from current therapy to dabigatran etexilate /rivaroxaban for this indication should be carried out by clinicians with an interest in stroke prevention and management of atrial fibrillation. It may be appropriate for GP practices that provide level 3 and 4 anticoagulation services to make the decision to switch to dabigatran etexilate /rivaroxaban, depending on health board service models. 15

16 All Wales Medicines Strategy Group Additional guidance to prescribers: 1. To support the recognition of the newer oral anticoagulants, prescribers are encouraged to add the indication to the dosing instructions. For example, take once/twice daily for anticoagulation to prevent (stroke/dvt/etc). 2. Blood testing/clinical monitoring: A systematic assessment of the issues of prescribing responsibility for dabigatran etexilate and rivaroxaban are outlined in Appendix 2. A pragmatic approach would be to perform, at minimum: baseline clotting screen; baseline and annual full blood count; renal and liver function tests, for patients requiring oral anticoagulation. Annual blood monitoring is consistent with current common practice for monitoring patients with cardiovascular disease in primary care. Close clinical surveillance (looking for signs of bleeding or anaemia) is recommended throughout the treatment period, especially if risk factors are combined Assessment of renal function: AWMSG notes that assessment of renal function, according to the SPC for dabigatran etexilate, the ESC guidelines and the British National Formulary (BNF), should be performed using creatinine clearance (CrCl). Guidance regarding the use of egfr as a proxy measure is under consideration. MHRA statement: As exposure to dabigatran is substantially increased in patients with renal insufficiency, renal function should be assessed in all patients before starting dabigatran and at least once a year in patients older than 75 years or those with a suspected decline in renal function. 22 The 2012 ESC guidelines for the management of atrial fibrillation state: the assessment of renal function (by CrCl) is mandatory for all new oral anticoagulants, but especially for patients taking dabigatran. Indeed, renal function should be assessed annually in patients with normal (CrCl 80 ml/min) or mild (CrCl ml/min) renal impairment, and perhaps 2 3 times per year in patients with moderate (i.e. creatinine clearance ml/min) renal impairment The AWMSG document Warfarin Monitoring (2012) includes guidance on the initiation, annual assessment and monitoring of warfarin therapy

17 All Wales Advice on the Role of Oral Anticoagulants for the Prevention of Stroke and Systemic Embolism in People with Atrial Fibrillation 4.0 LEVEL OF INR CONTROL 4.1 Where warfarin is prescribed, time in therapeutic range should not be assessed within the initiation period (normally 1 3 months). The recommendation to initiate warfarin using a slow-loading regimen for patients with atrial fibrillation who do not require rapid anticoagulation should be noted 14. The AWMSG anticoagulation audit (2008) identified patients who had initiated warfarin in the previous year as a higher risk cohort 23. It was noted that, while many people will be stabilised within one month of initiating warfarin, experience in daily practice would suggest that a longer initiation timeframe would be appropriate for some people. 4.2 A monitoring period of six months (after the initiation period) would give a good indication of time in therapeutic range. People stabilised on warfarin for atrial fibrillation may require infrequent INR blood tests. A monitoring period of three months for time in therapeutic range may include a very small number of readings. A period of six months (after the initiation period) would give a good indication of time in therapeutic range. 4.3 Ability to measure time in therapeutic range is advised 5. National Patient Safety Agency (NPSA) Patient Safety Alert 18 recommended: NHS and independent sector organisations in England and Wales take the following steps: Audit anticoagulant services using BSH/NPSA [British Society for Haematology/National Patient Safety Agency] safety indicators as part of the annual medicines management audit programme. The audit results should inform local actions to improve the safe use of anticoagulants, and should be communicated to clinical governance, and drugs and therapeutics committees (or equivalent). This information should be used by commissioners and external organisations as part of the commissioning and performance management process. Safety indicators for patients starting oral anticoagulant treatment: 1. Percentage of patients following loading protocol. 2. Percentage of patients developing INR > Percentage of patients in therapeutic range at discharge Unexplained, recurrent extreme INR variation is a useful alternative marker of INR control in addition to time in therapeutic range. If prescribers identify extreme INRs, medicines adherence should be considered, as outlined in Statement 2.4. Observation of extreme INRs can be useful for locations that do not currently have the electronic facility to calculate an individual s time in therapeutic range or percentage of INRs in range. NPSA recommends the secondary measure of percentage of INRs in range if unable to measure proportion of patient time in range because of inadequate decision/support software 5. If prescribers identify extreme INRs, medicines adherence should be considered, as outlined in Statement

18 All Wales Medicines Strategy Group 5.0 ADDITIONAL CONSIDERATIONS 5.1 All suspected adverse reactions to dabigatran etexilate /rivaroxaban should be reported directly to the MHRA through the Yellow Card Scheme using the electronic form at or the cards available in the back of the BNF. The 2012 ESC guidelines for the management of atrial fibrillation note that since there is still limited experience with these agents, strict adherence to approved indications and careful post-marketing surveillance are strongly recommended 9. The use of a nationally agreed risk assessment chart for all patients initiated on oral anticoagulants, as outlined above (see Statement 1.3 [Example of good practice]), could support the collection of data. 18

19 All Wales Advice on the Role of Oral Anticoagulants for the Prevention of Stroke and Systemic Embolism in People with Atrial Fibrillation References 1 National Institute for Health and Clinical Excellence. Technology Appraisal 249. Dabigatran etexilate for the prevention of stroke and systemic embolism in atrial fibrillation. Mar Available at: Accessed Jul National Institute for Health and Clinical Excellence. Technology Appraisal 256. Rivaroxaban for the prevention of stroke and systemic embolism in people with atrial fibrillation. May Available at: Accessed Jul Wallentin L, Yusuf S, Ezekowitz MD et al. Efficacy and safety of dabigatran compared with warfarin at different levels of international normalised ratio control for stroke prevention in atrial fibrillation: an analysis of the RE-LY trial. The Lancet 2010; 376 (9745): Connolly SJ, Pogue JE, Eikelboom J et al. Benefit of oral anticoagulant over antiplatelet therapy in atrial fibrillation depends on the quality of international normalized ratio control achieved by centers and countries as measured by time in therapeutic range. Circulation 2008; 118 (20): National PAtient Safety Agency. Actions that can make anticoagulant therapy safer: Alert and other information. Mar Available at: C18%C2%AC. Accessed Jul European Heart Rhythm Association (EHRA), European Association for Cardio- Thoracic Surgery (EACTS), Camm AJ et al. Guidelines for the management of atrial fibrillation. European Heart Journal 2010; 31 (19): Patel MR, Mahaffey KW, Garg J et al. Rivaroxaban versus warfarin in nonvalvular atrial fibrillation. New England Journal of Medicine 2011; 365 (10): Mason PK, Lake DE, DiMarco JP et al. Impact of the CHA 2 DS 2 -VASc score on anticoagulation recommendations for atrial fibrillation. The American journal of medicine 2012; 125 (6): Camm AJ, Lip GYH, De Caterina R et al focused update of the ESC Guidelines for the management of atrial fibrillation. European Heart Journal Andersson P, Löndahl M, Abdon NJ et al. The prevalence of atrial fibrillation in a geographically well-defined population in Northern Sweden: implications for anticoagulation prophylaxis. Journal of Internal Medicine 2012; 272 (2): Gage BF, Waterman AD, Shannon W et al. Validation of clinical classification schemes for predicting stroke: Results from the national registry of atrial fibrillation. JAMA: The Journal of the American Medical Association 2001; 285 (22): Lip GYH, Frison L, Halperin JL et al. Identifying patients at high risk for stroke despite anticoagulation. Stroke 2010; 41 (12): British Medical Association, NHS Employers. Quality and Outcomes Framework for 2012/13. Guidance for PCOs and practices Available at: Accessed Aug

20 All Wales Medicines Strategy Group 14 All Wales Medicines Strategy Group. Warfarin monitoring. Jul Available at: Accessed Jul Cardiff and Vale University Health Board. Atrial Fibrillation: stroke risk assessment and antithrombotic treatment recommendation. Jun Connolly SJ, Ezekowitz MD, Yusuf S et al. Dabigatran versus warfarin in patients with atrial fibrillation. N Engl J Med 2009; 361 (12): Healthcare Improvement Scotland. Prevention of stroke and systemic embolism in adult patients with non-valvular atrial fibrillation. Apr Available at: Accessed Jul Boehringer Ingelheim Ltd. Pradaxa. Summary of Product Characteristics. Aug Available at: capsules/. Accessed Jul Bayer plc. Xarelto. Summary of Product Characteristics. Sep Available at: Accessed Jul National Institute for Health and Clinical Excellence. Clinical Guideline 76: Medicines adherence: involving patients in decisions about prescribed medicines and supporting adherence. Jan Available at: Accessed Jul Vrijens B, De Geest S, Hughes DA et al. A new taxonomy for describing and defining adherence to medications. British Journal of Clinical Pharmacology 2012; 73 (5): Medicines and Healthcare products Regulatory Agency. Drug Safety Update. Dabigatran (Pradaxa ): risk of serious haemorrhage - contraindications clarified and reminder to monitor renal function. Jul Available at: Accessed Aug All Wales Medicines Strategy Group. AWMSG Prescribing Incentive Scheme. General Practice Audit: oral anticoagulants Available at: ation%20issued%20may08%20v1.0.doc. Accessed Aug All Wales Medicines Strategy Group. Criteria for Shared Care Available at: 5%2008.pdf. Accessed May General Medical Council. Good practice in prescribing medicines - guidance for doctors Available at: Accessed Aug Review date: October