Sarah Jennings , BSc, BScPhm, RPh, PharmD , Janice Mann , BSc(Hon Bio and Psych), MD
We read with interest the Point Counterpoint column in the September–October 2012 issue of the Canadian Journal of Hospital Pharmacy . Kertland1 and Tejani2 highlighted many important issues in their debate about whether new oral anticoagulants should replace warfarin for prophylaxis of thromboembolism in Canadians with atrial fibrillation.
We would like to clarify one point regarding the review by the Canadian Agency for Drugs and Technologies in Health (CADTH) on the optimal use of warfarin. CADTH did recommend a well-coordinated, structured approach to warfarin management,3 but it did not recommend that care be “dedicated to anticoagulation therapy”, as stated by Kertland.1
The best available evidence is unclear as to whether specialized anticoagulation clinics result in improved outcomes for patients. What does matter is a structured approach, including a clear plan for patient follow-up, use of a validated dosing tool, ongoing patient education, and involvement of caregivers and other health professionals. This type of care can take place in a specialized anticoagulation clinic, a family doctor’s or specialist’s office, or other care settings.
CADTH continues to focus on prevention of stroke among patients with atrial fibrillation. A systematic review and network meta-analysis, comparing the new oral anticoagulants with warfarin, was completed in April 2012.4 The best available evidence to date suggests that the benefit of the new oral anticoagulants is small, their long-term safety is unknown, and the new drugs are more expensive even when warfarin monitoring is taken into account.
Expert recommendations based on the review were made in June 2012, with warfarin being recommended as first-line therapy for patients with nonvalvular atrial fibrillation.5
An extension of this review, which will include antiplatelet agents such as acetylsalicylic acid and clopidogrel, will be available in spring 2013. All CADTH reports are freely available at the organization’s website (www.cadth.ca/anticoagulants), which readers may visit for additional information.
1. Kertland H. Should direct thrombin inhibitors replace warfarin for prophylaxis of thromboembolism in Canadians with atrial fibrillation? The “pro” side. Can J Hosp Pharm. 2012;65(5):401–3.
2. Tejani AM. Should direct thrombin inhibitors replace warfarin for prophylaxis of thromboembolism in Canadians with atrial fibrillation? The “con” side. Can J Hosp Pharm. 2012;65(5):403–5.
3. Recommendations for optimal warfarin management for prevention of thromboembolic events in patients with atrial fibrillation. Optimal Use Report, Volume 1, Issue 2c. Ottawa (ON): Canadian Agency for Drugs and Technologies in Health; 2011 Nov [cited 2013 Jan 24]. Available from: www.cadth.ca/media/pdf/OP0508_warfarin_rec-report_e.pdf
4. Wells G, Coyle D, Cameron C, Steiner S, Coyle K, Kelly S, et al. Safety, effectiveness, and cost-effectiveness of new oral anticoagulants compared with warfarin in preventing stroke and other cardiovascular events in patients with atrial fibrillation. Ottawa (ON): Canadian Collaborative for Drug Safety, Effectiveness and Network Meta-Analysis; 2012 Apr [cited 2013 Feb 12]. Available from: www.cadth.ca/media/pdf/NOAC_Therapeutic_Review_final_report.pdf
5. CADTH therapeutic review recommendations: New oral anticoagulants for the prevention of thromboembolic events in patients with atrial fibrillation. Ottawa (ON): Canadian Agency for Drugs and Technologies in Health; 2012 Jun [cited 2013 Feb 12]. Available from: www.cadth.ca/media/pdf/tr0002_New-Oral-Anticoagulants_rec_e.pdf
Competing interests: None declared.
Canadian Journal of Hospital Pharmacy , VOLUME 66 , NUMBER 2 , March-April 2013