Background
Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia, occurring in 1–2% of the general population. The main goal of AF treatment is to avoid thromboembolic events (fivefold increased risk compared with those in sinus rhythm) by instituting antithrombotic therapy.
Warfarin treatment prevents 64% of strokes in patient with non valvular AF but can be problematic due to food and drug interactions, need for frequent monitoring of international normalized ratio (INR), difficult to maintain in therapeutical range and risk of bleeding.
Based on the results of RE-LY trial Dabigatran etexilate (a reversible direct thrombin inhibitor) was included in Europe, North America and Canada guidelines of AF management as an alternative to warfarin for thromboembolic prophylaxis. Dabigatran was superior to warfarin in preventing stroke and systemic embolism (SE), with fewer total intracranial hemorrhages (ICH), hemorrhagic strokes (HS), ischemic strokes but a slight increase in extracranial hemorrhages and acute myocardial infarctions.
Knowledge Gap
Dabigatran etexilate started to be used widely in the clinical practice. However the cost-effectiveness of this new treatment remains to be established.
Aim of the Study
Such an economic evaluation was assessed by the authors of the present study who estimated the cost-effectiveness of dabigatran versus warfarin, aspirin and no therapy using a Markov model.
Methods
In this study the authors considered two cohorts of patients with AF (starting age <80 and ≥ 80 years) and the outcomes included clinical events normalized for 100 patient-years, quality-adjusted life years (QALYs), total costs and incremental cost-effectiveness ratios (ICER).
Results
For the population < 80 years the ICER was £4831/QALY and for those initiating treatment ≥80 years was £7090/QALY gained versus warfarin with a probability of cost-effectiveness at £20000/QALYs gained of 98% and 63%, respectively.
Conclusion
The supplemental costs of dabigatran seems not to overcome the benefit of the significant reduction in catastrophic events (IS, ICH and HS). Low ICER makes dabigatran suitable for patients with high stroke and bleeding risks such as frail older people with multiple comorbidities and polypharmacy in whom anticoagulation monitoring is erratic.
Perspective-Clinical Impact
Findings of the present study should be considered in line with findings from other studies. Kamel et al., addressed the same cost-effectiveness using a population of patients ≥ 70 years with non-valvular AF. Dabigatran was associated with 4.27 QALYs compared with 3.91 QALYs with warfarin, providing 0.36 additional QALYs at a cost of $9000. However, Ali et al., investigated the cost of dabigatran treatment vs. warfarin in a population of 402 patients with AF (the mean age was 72.3, range 34-94 years).
The study showed that the annual cost of treatment with dabigatran was £1.573 compared with £207 for warfarin, which conducted to a significantly raise of the prevention’s costs of stroke per year (£6,219 for warfarin and £28,086.5 and £25,181 for dabigatran 110 mg bid and respectively 150 mg bid).
Further reading
Kamel H., Johnston S.C., Easton J.D., Kim A.S. – Cost-Effectiveness of Dabigatran Compared With Warfarin for Stroke Prevention in Patients With Atrial Fibrillation and Prior Stroke or Transient Ischemic Attack, Stroke 2012; 43:881-883
Ali A., Bailey C., Abdelhafiz A.H. – Stroke prophylaxis with warfarin or dabigatran for patients with non-valvular atrial fibrillation-cost analysis, Age and Aging 2012; 0:1-4
Citation: Heart. 2012 Apr;98(7):573-8