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Impact of Warfarin on Atrial-Fibrillation Outcomes Related to Economic Consumption Patterns: Hospitalization, Cost, and Mortality may be Predictable and Modifiable at the Population Level

Abstract

Introduction

Warfarin reduces atrial fibrillation (AF)-related strokes and may impact mortality, hospitalizations, and costs. This study investigated the possibility that patterns of warfarin consumption are associated with the frequency of acute events.

Methods

Annual cost profiles of 9.2 million Medicare beneficiaries with AF were analyzed to identify patterns of benefits consumption from 2000 through 2010. Beneficiaries were divided into five consumption clusters based upon their annual cost profiles, ranging from crisis consumers at the high end to low consumers. Resource-utilization patterns and outcome differences were calculated between AF beneficiaries who received warfarin and those who did not. Propensity score-matched analysis was performed to reduce selection bias.

Results

The annual percentages of beneficiaries and expenditures that differentiated each cluster showed stable patterns. Warfarin use influenced consumption patterns and outcomes. The most important financial difference between higher and lower consumers was inpatient cost. AF beneficiaries on warfarin had lower annual cost profiles and had a higher propensity to persist in or migrate to consumption clusters with comparatively small reimbursement claims and lower hospitalization risks. AF beneficiaries not on warfarin had higher cost and mortality.

Conclusions

These data signal that a nontrivial portion of acute events (hospitalization and mortality) are amenable to medical intervention (warfarin). When acute events are amenable to medical intervention and occur at a higher frequency because guidelines have not been applied evenly across affected populations, it is appropriate to define those occurrences as disparities associated with systemic failure in evidence-based medicine. Quality-improvement initiatives that reduce therapeutic disparities may result in lower cost and improved outcomes.

Funding

No funding or sponsorship was received for this study or publication of this article.

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References

  1. 1.

    January CT, Wann S, Alpert JS, et al. ACC/AHA/HRS guideline for the management of patients with atrial fibrillation: a report of the American College of cardiology/American Heart Association task force on practice guidelines and the heart rhythm society. J Am Coll Cardiol. 2014;. doi:10.1016/j.jacc.2014.03.022.

    PubMed  Google Scholar 

  2. 2.

    Skanes AC, Healey JS, Cairns JA, et al. Focused 2012 update of the Canadian cardiovascular society atrial fibrillation guidelines: recommendations for stroke prevention and rate/rhythm control. Can J Cardiol. 2012;28(2):125–36. doi:10.1016/j.cjca.2012.01.021.

    Article  PubMed  Google Scholar 

  3. 3.

    Camm AJ, Lip GYH, Caterina RD, et al. 2012 focused update of the ESC guidelines for the management of atrial fibrillation: an update of the 2010 ESC Guidelines for the Management of Atrial Fibrillation: developed with the special contribution of the European Heart Rhythm Association. Eur Heart J. 2012;33(21):2719–47. doi:10.1093/eurheartj/ehs253.

    Article  PubMed  Google Scholar 

  4. 4.

    Guyatt GH, Akl EA, Crowther M, et al. Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines. Chest 2012;141(2_suppl):1S–70S, e1S–e8012S. Available at: http://journal.publications.chestnet.org/article.aspx?articleID=1159396. Accessed February 6, 2014.

  5. 5.

    Bungard TJ, Ghali WA, Teo KK, McAlister FA, Tsuyuki RT. Why do patients with atrial fibrillation not receive warfarin? Arch Intern Med. 2000;160(1):41–6.

    CAS  Article  PubMed  Google Scholar 

  6. 6.

    Brass LM, Krumholz HM, Scinto JD, Mathur D, Radford M. Warfarin use following ischemic stroke among Medicare patients with atrial fibrillation. Arch Intern Med. 1998;158:2093–100.

    CAS  Article  PubMed  Google Scholar 

  7. 7.

    Beyth RJ, Antani MR, Covinsky KE, et al. Why isn’t warfarin prescribed to patients with nonrheumatic atrial fibrillation? J Gen Intern Med. 1996;11(12):721–8.

    CAS  Article  PubMed  Google Scholar 

  8. 8.

    Darkow T, Vanderplas AM, Lew KH, Kim J, Hauch O. Treatment patterns and real-world effectiveness of warfarin in nonvalvular atrial fibrillation in a managed care system. Curr Med Res Opin. 2005;21(10):1583–94.

    CAS  Article  PubMed  Google Scholar 

  9. 9.

    Go AS, Hylek EM, Chang Y, et al. Anticoagulation therapy for stroke prevention in atrial fibrillation: how well do randomized trials translate into clinical practice? JAMA. 2003;290(20):2685–92.

    CAS  Article  PubMed  Google Scholar 

  10. 10.

    Kim MH, Lin J, Hussein M, Kreilick C, Battleman D. Cost of atrial fibrillation in United States managed care organizations. Adv Ther. 2009;26(9):847–57. doi:10.1007/s12325-009-0066-x.

    Article  PubMed  Google Scholar 

  11. 11.

    Kim MH, Johnston SS, Chu B-C, Dalal MR, Schulman KL. Estimation of total incremental health care costs in patients with atrial fibrillation in the United States. Circ Cardiovasc Qual Outcomes. 2011;4(3):313–20. doi:10.1161/CIRCOUTCOMES.110.958165.

    Article  PubMed  Google Scholar 

  12. 12.

    Lee S, Mullin R, Blazawski J, Coleman CI. Cost-effectiveness of apixaban compared with warfarin for stroke prevention in atrial fibrillation. PLoS ONE. 2012;7(10):e47473. doi:10.1371/journal.pone.0047473.

    CAS  Article  PubMed  PubMed Central  Google Scholar 

  13. 13.

    Shah SV, Gage BF. Cost-effectiveness of dabigatran for stroke prophylaxis in atrial fibrillation. Circulation. 2011;123:2562–70.

    Article  PubMed  Google Scholar 

  14. 14.

    Coyne KS, Paramore C, Grandy S, Mercader M, Reynolds M, Zimetbaum P. Assessing the direct costs of treating nonvalvular atrial fibrillation in the United States. Value Health. 2006;9(5):348–56.

    Article  PubMed  Google Scholar 

  15. 15.

    Lee WC, Lamas GA, Balu S, Spalding J, Wang Q, Pashos CL. Direct treatment cost of atrial fibrillation in the elderly American population: a medicare perspective. J Med Econ. 2008;11(2):281–98.

    PubMed  Google Scholar 

  16. 16.

    Lakshminarayan K, Solid CA, Collins AJ, Anderson DC, Herzog CA. Atrial fibrillation and stroke in the general medicare population: a 10-year perspective (1992 to 2002). Stroke. 2006;37:1969–74.

    Article  PubMed  Google Scholar 

  17. 17.

    Rosenbaum PR, Rubin DB. The central role of the propensity score in observational studies for causal effects. Biometrika. 1983;79:516–24.

    Google Scholar 

  18. 18.

    Rubin DB, Thomas N. Matching using estimated propensity score: relating theory to practice. Biometrics. 1996;52:249–64.

    CAS  Article  PubMed  Google Scholar 

  19. 19.

    Stuart EA. Matching methods for causal inference: a review and a look forward. Stat Sci. 2010;25:1–21.

    Article  PubMed  PubMed Central  Google Scholar 

  20. 20.

    Austin PC. Balance diagnostics for comparing the distribution of baseline covariates between treatment groups in propensity-score matched samples. Stat Med. 2009;28:3083–107.

    Article  PubMed  PubMed Central  Google Scholar 

  21. 21.

    Rutstein DD, Berenberg W, Chalmers TG, et al. Measuring the quality of medical care—a clinical method. N Engl J Med. 1976;294(11):582–8.

    CAS  Article  PubMed  Google Scholar 

  22. 22.

    Nolte E, McKee M. Does Health Care Save Lives? Avoidable Mortality Revisited. London: The Nuffield Trust, 2004:[PROVIDE SPECIFIC PAGE NO.]. Available at: http://www.nuffieldtrust.org.uk/publications/does-healthcare-save-lives-avoidable-mortality-revisited. Accessed July 12, 2013.

  23. 23.

    Go AS, Fang MC, Singer DE. Antithrombotic therapy for stroke prevention in atrial fibrillation. Prog Cardiovasc Dis. 2005;48(2):108–24. doi:10.1016/j.pcad.2005.06.007.

    CAS  Article  PubMed  Google Scholar 

  24. 24.

    Kirley K, Qato DM, Kornfield R, Stafford RS, Alexander GC. National trends in oral anticoagulant use in the United States, 2007 to 2011. Circ Cardiovasc Qual Outcomes. 2012;5(5):615–21. doi:10.1161/CIRCOUTCOMES.112.967299.

    Article  PubMed  PubMed Central  Google Scholar 

  25. 25.

    Masoudi FA, Ponirakis A, Yeh RW, et al. Cardiovascular care facts: a report from the National Cardiovascular Data Registry: 2011. J Am Coll Cardiol. 2013;62(21):1931–47. doi:10.1016/j.jacc.2013.05.099.

    Article  PubMed  Google Scholar 

  26. 26.

    Benjamin EJ, Chen P-S, Bild DE, et al. Prevention of atrial fibrillation: report from a National Heart, Lung, and Blood Institute workshop. Circulation. 2009;119:608–18.

    Article  Google Scholar 

  27. 27.

    Eisenhart E, Herr A, Hickey C, et al. Medicare and Atrial Fibrillation/Consequences in Cost and Care. Washington, DC: Avalere Health, LLC, September 2009:1–2. Available at: http://products.sanofi.us/resources/Medicare%20and%20AFib.pdf. Accessed July 12, 2013.

  28. 28.

    Ovbiagele B, Goldstein LB, Higashida RT, et al. Forecasting the future of stroke in the United States: a policy statement from the American Heart Association and American Stroke Association. Stroke. 2013;44(8):2361–75. doi:10.1161/STR.0b013e31829734f2.

    Article  PubMed  Google Scholar 

  29. 29.

    Congdon P, Cai Q, Puckrein G, Xu L. Predicting risks of increased morbidity among atrial fibrillation patients using consumption classes. Int J Stat Med Res. 2014;3:203–14.

    Article  Google Scholar 

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Acknowledgments

No funding or sponsorship was received for this study or publication of this article.

All named authors meet the International Committee of Medical Journal Editors (ICMJE) criteria for authorship for this manuscript, take responsibility for the integrity of the work as a whole, and have given final approval for the version to be published.

Disclosures

Liou Xu is an employee of the NMQF. Gary A. Puckrein is an employee of the NMQF. Michael H. Kim and Qiang Cai have nothing to disclose.

Compliance with Ethics Guidelines

This article does not contain any new studies with human or animal subjects performed by any of the authors.

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Correspondence to Michael H. Kim.

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Kim, M.H., Cai, Q., Xu, L. et al. Impact of Warfarin on Atrial-Fibrillation Outcomes Related to Economic Consumption Patterns: Hospitalization, Cost, and Mortality may be Predictable and Modifiable at the Population Level. Adv Ther 33, 1579–1599 (2016). https://doi.org/10.1007/s12325-016-0387-5

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Keywords

  • Atrial fibrillation
  • Cardiology
  • Cost
  • Hospitalization
  • Mortality
  • Outcomes
  • Warfarin