Should Hemodialysis Patients With Atrial Fibrillation Undergo Systemic Anticoagulation? A Cost-Utility Analysis.
Quinn RR, Naimark DM, Oliver MJ, Bayoumi AM. Am J Kidney Dis. 2007 Sep;50(3):421-32
Related Articles:
- The intersection of risk and benefit: is warfarin anticoagulation suitable for atrial fibrillation in patients on hemodialysis?
- Impact of Proteinuria and Glomerular Filtration Rate on Risk of Thromboembolism in Atrial Fibrillation: The Anticoagulation and Risk Factors in Atrial Fibrillation (ATRIA) Study.
- Warfarin Anticoagulation in Hemodialysis Patients: A Systematic Review of Bleeding Rates.
Abstract:
BACKGROUND: Approximately 14% of hemodialysis patients have atrial fibrillation. Hemodialysis patients with atrial fibrillation appear to be at increased risk of both thromboembolic complications and bleeding. Furthermore, there is uncertainty regarding the efficacy of warfarin or acetylsalicylic acid (ASA) therapy for preventing strokes in this subgroup because they were excluded from relevant trials. STUDY DESIGN: We performed a cost-utility analysis. Probabilistic sensitivity analysis was used to incorporate parameter uncertainty into the model. Expected value of perfect information and scenario analyses were performed to identify the important drivers of the decision and focus future research. SETTING & POPULATION: Base case was a 60-year-old male hemodialysis patient in the United States. MODEL, PERSPECTIVE, & TIME FRAME: A Markov Monte Carlo microsimulation model was constructed from the perspective of the health care payer, and patients were followed up during their lifetime. INTERVENTION: We compared 3 alternative treatment strategies for permanent atrial fibrillation in hemodialysis patients: warfarin, ASA, or no treatment. OUTCOMES: Quality-adjusted survival and cost. RESULTS: ASA and warfarin both prolonged survival compared with no treatment (0.06 and 0.15 quality-adjusted life-years [QALYs], respectively). ASA was associated with an incremental cost-effectiveness ratio of $82,100/QALY. Warfarin provided additional benefits at a cost of $88,400 for each QALY gained relative to ASA. At a threshold of $100,000/QALY, the probabilities that no treatment, warfarin, and ASA were the most efficient therapy were 20%, 58%, and 23%, respectively. LIMITATIONS: Parameterization data and costs were taken from US studies and may not be generalizable to other countries. Peritoneal dialysis patients were not included in the analysis. CONCLUSIONS: The high future cost of hemodialysis constrains incremental cost-effectiveness ratios to values greater than commonly cited thresholds ($50,000/QALY). Based on available evidence, warfarin appears to be the optimal therapy to prevent thromboembolic stroke in hemodialysis patients with atrial fibrillation. Additional study is required to determine the efficacy of warfarin and risk of bleeding complications in this population so that patients can make a more informed choice.
September 16th, 2007 at 11:33 pm
Dr. Quinn,
There are 2 recent papers (1 in the same AJKD issue your paper was published in) that discuss the risk of bleeding in dialysis patients who receive anticoagulation:
Meghan J. Elliott, Deborah Zimmerman, Rachel M. Holden
Warfarin Anticoagulation in Hemodialysis Patients: A Systematic Review of Bleeding Rates
AJKD Volume 50, Issue 3, Pages 433-440 (September 2007)http://journals.elsevierhealth.com/periodicals/yajkd/article/PIIS027263860700950X/abstract
ANDREW CY TO, MAHA YEHIA and JOHN F COLLINS
Atrial fibrillation in haemodialysis patients: Do the guidelines for anticoagulation apply?
Nephrology October 2007 – Vol. 12 Issue 5 pages 441–447
http://www.blackwell-synergy.com/doi/abs/10.1111/j.1440-1797.2007.00835.x
Does this new information affect your conclusions in any way?
September 17th, 2007 at 11:34 pm
For those of you with full text access to AJKD, there is an interesting editorial that accompanies this article:
http://www.ajkd.org/article/PIIS0272638607010311/fulltext
September 19th, 2007 at 11:34 pm
That’s a great question and two interesting articles. In my opinion, they reinforce our conclusion that we are lacking important information about the risk of stroke in dialysis patients with atrial fibrillation, the efficacy of warfarin in reducing the risk of stroke, and the bleeding risk associated with warfarin use. It argues strongly for clinical trials in this population so that we can adequately inform decision-making.
To address your question specifically, the bleeding risks outlined in the Elliott paper are within the range considered in our analysis. If you believe existing data on the risk of stroke and that warfarin reduces the risk of stroke in dialysis patients to the same degree that it has been shown to in the general population, warfarin would be the best strategy based on existing data.
I only have access to the abstract from the To paper at the moment, but they report a risk of major bleeding that is three times the risk of cerebrovascular accidents. Under situations where the risk of stroke is similar in Afib and non-afib groups of dialysis patients, and the risk of bleeding is high, Warfarin is still the optimal strategy given the assumptions above.
The purpose of using decision analysis to examine this question was to really take a hard look at what drives decision making and patient outcomes. Strokes can have devastating consequences that, if a patient survives, have a significant impact on quality of life long-term. Major bleeding episodes, while serious, have a much lower mortality rate. If you survive, you generally are not left with residual disability, and so quality of life isn’t impacted for very long. This is why the results seem so robust to changes in the bleeding rates. There is also some interesting work done by Devereaux et al that suggests patients are much more tolerant of serious bleeding events in order to prevent strokes (Devereaux PJ, et al BMJ 2001 323:1-7) than physicians are. There is a limit to this, however and that’s why it would be important to gather better information about bleeding rates.
This brings me back to my initial comment. We need to know the risks and benefits of treatment with warfarin in this population in order to adequately inform patient and physician decision-making. There are significant enough differences between dialysis patients and the general population that we can’t simply “borrow” data from randomized trials that were done in a highly selected group. I think this area requires more investigation and more debate. I hope our article will stimulate that.