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Hamostaseologie 1997; 17(03): 166-169
DOI: 10.1055/s-0038-1659985
Originalarbeiten/Original Articles
Schattauer GmbH

Stroke Prevention in Non-Valvular Atrial Fibrillation

The Price of Doing Nothing
J. Jaime Caro
1   Division of General Internal Medicine, Royal Victoria Hospital, McGill University, Montreal, Canada
2   Caro Research, Boston, USA
,
Judith A. O’Brien
2   Caro Research, Boston, USA
,
Wendy S. Klittich
2   Caro Research, Boston, USA
› Author Affiliations
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Publication History

Publication Date:
27 June 2018 (online)

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Summary

Despite evidence from 6 major clinical trials that warfarin effectively prevents strokes in atrial fibrillation, clinicians and health care managers may remain reluctant to support anticoagulant prophylaxis because of its perceived costs. Yet, doing nothing also has a price. To assess this, we carried out a pharmacoe-conomic analysis of warfarin use in atrial fibrillation. The course of the disease, including the occurrence of cerebral and systemic emboli, intracranial and other major bleeding events, was modeled and a meta-analysis of the clinical trials and other relevant literature was carried out to estimate the required probabilities with and without warfarin use. The cost of managing each event, including acute and subsequent care, home care equipment and MD costs, was derived by estimating the cost per resource unit, the proportion consuming each resource and the volume of use. Unit costs and volumes of use were determined from established US government databases, all charges were adjusted using cost-to-charge ratios, and a 3% discount rate was applied to costs incurred beyond the first year. The proportions of patients consuming each resource were estimated by fitting a joint distribution to the clinical trial data, stroke outcome data from a recent Swedish study and aggregate ICD-9 specific, Massachusetts discharge data. If nothing is done, 3.2% more patients will suffer serious emboli annually and the expected annual cost of managing a patient will increase by DM 2,544 (1996 German Marks), from DM 4,366 to DM 6,910. Extensive multiway sensitivity analyses revealed that the higher price of doing nothing persists except for very extreme combinations of inputs unsupported by literature or clinical standards. The price of doing nothing is thus so high, both in health and economic terms, that cost-consciousness as well as clinical considerations mandate warfarin prophylaxis in atrial fibrillation.

Keywords

Atrial fibrillation - cost-effectiveness - stroke
 

  • REFERENCES

  • 1 Cairns J.A, Connolly S.J. Nonrheumatic atrial fibrillation. Risk of stroke and role of antithrombotic therapy. Circulation 1991; 84: 469-81.
    CrossrefPubMedGoogle Scholar
  • 2 Laupacis A, Albers G, Dunn M.I, Feinberg W.M. Antithrombotic therapy in atrial fibrillation. Chest 1992; 102 (Suppl. 04) 426S-33S.
    CrossrefPubMedGoogle Scholar
  • 3 Albers G.W. Atrial fibrillation and stroke. Three new studies, three remaining questions. Arch Intern Med 1994; 154: 1443-8.
    CrossrefPubMedGoogle Scholar
  • 4 Laupacis A. Anticoagulants for atrial fibrillation. Lancet 1993; 342: 1251-2.
    CrossrefPubMedGoogle Scholar
  • 5 Whittle J, Wickenheiser L, Venditti L.N. Is Warfarin underused in the treatment of elderly persons with atrial fibrillation?. Arch Intern Med 1997; 157: 441-5.
    CrossrefPubMedGoogle Scholar
  • 6 Stafford R.S, Singer D.E. National patterns of warfarin use in atrial fibrillation. Arch Intern Med 1996; 156: 2537-41.
    CrossrefPubMedGoogle Scholar
  • 7 Palareti G, Leali N, Coccheri S. et al. Bleeding complications of oral anticoagulant treatment: an inception-cohort, prospective collaborative study (ISCOAT). Lancet 1996; 348: 423-8.
    CrossrefPubMedGoogle Scholar
  • 8 Hylek E.M, Skates S.J, Sheehan M.A, Singer D.E. An analysis of the lowest effective intensity of prophylactic anticoagulation for patients with nonrheumatic atrial fibrillation. N Engl J Med 1996; 335 (08) 540-6.
    CrossrefPubMedGoogle Scholar
  • 9 O’Brien J.A, Caro J.J, Klittich W.S. Beyond acute care: the true cost of stroke. Clin Therapeut 1996; 149: 21.
    PubMedGoogle Scholar
  • 10 Caro J.J, O’Brien J.A, Klittich W.S, Jackson J.D. The economic impact of warfarin prophylaxis in non-valvular atrial fibrillation. J Disease Management and Clinical Outcomes; in press.
    PubMedGoogle Scholar
  • 11 Eckman M.H, Levine H.J, Pauker S.G. Decision analytic and cost-effectiveness issues concerning anticoagulant prophylaxis in heart disease. Chest 1992; 102: 538S-49S.
    CrossrefPubMedGoogle Scholar
  • 12 Petersen P, Boysen G, Godtfredsen J, Andersen E, Andersen B. Placebo-controlled, randomized trial of warfarin and aspirin for prevention of thromboembolic complications in chronic atrial fibrillation. The Copenhagen AFASAK Study. Lancet 1989; Jan 29: 175-8.
    PubMedGoogle Scholar
  • 13 The Boston Area Anticoagulation Trial for Atrial Fibrillation Investigators. The effect of low-dose warfarin on the risk of stroke in patients with nonrheumatic atrial fibrillation. N Engl J Med 1990; 323: 1505-11.
    CrossrefPubMedGoogle Scholar
  • 14 Stroke Prevention in Atrial Fibrillation Investigators. Stroke Prevention in Atrial Fibrillation Study. Final results. Circulation 1991; 84: 527-39.
    CrossrefPubMedGoogle Scholar
  • 15 Ezekowitz M.D, Bridgers L.S, James K.E. et al. Warfarin in the prevention of stroke associated with nonrheumatic atrial fibrillation. N Eng J Med 1992; 327: 1406-12.
    CrossrefPubMedGoogle Scholar
  • 16 Connolly S.J, Laupacis A, Gent M, Roberts R.S, Cairns J.A. The CAFA Study Coinvestigators. Canadian Atrial Fibrillation anticoagulation (CAFA) Study. J Am Coll Cardiol. 1991; 18: 349-55.
    CrossrefPubMedGoogle Scholar
  • 17 Stroke Prevention in Atrial Fibrillation Investigators. Warfarin versus aspirin for prevention of thromboembolism in atrial fibrillation: Stroke Prevention in Atrial Fibrillation II study. Lancet 1994; 343: 687-91.
    PubMedGoogle Scholar
  • 18 Caro J.J, Groome P.A, Flegel K.M. Atrial fibrillation and anticoagulation: from randomized trials to practice. Lancet 1993; 341: 1381-4.
    CrossrefPubMedGoogle Scholar
  • 19 Thorngren M, Westling B. Rehabilitation and achieved health quality after stroke. A population-based study of 528 hospitalized cases followed for on year. Acta Neurol Scand 1990; 84: 374-80.
    PubMedGoogle Scholar
  • 20 Thorngren M, Westing B. Utilization of health care resources after stroke. A population-based study of 258 hospitalized cases followed during the first year. Acta Neurol Scand 1991; 84: 303-10.
    CrossrefPubMedGoogle Scholar
  • 21 Dennis M.S, Burn J.P.S, Sandercock P.A.G. et al. Long-term survival after first-ever stroke: The Oxfordshire Community Stroke Project. Stroke 1993; 24: 796-800.
    CrossrefPubMedGoogle Scholar
  • 22 The Dutch TIA Trial Study Group. A comparison of two doses of aspirin (30 mg vs 283 mg a day) in patients after a transient ischemic attack or minor ischemic stroke. N Engl J Med 191 325: 1261-6.
    PubMedGoogle Scholar
  • 23 Steering Committee of the Physicians’ Health Study Research Group. Final report on the aspirin component of the ongoing physicians’ health study. N Engl J Med 1989; 321: 129-35.
    CrossrefPubMedGoogle Scholar
  • 24 UK-TIA Study Group. United Kingdom Transient Ischemic Attack (UK-TIA) aspirin trial interim results. Br Med J 1988; 296: 316-20.
    CrossrefPubMedGoogle Scholar
  • 25 Hirsh H, Dalen J.E, Deykin D. et al. Oral anticoagulants mechanism for action, clinical effectiveness, and optimal therapeutic range. Chest 1992; 102: 312S-23S.
    PubMedGoogle Scholar
  • 26 Gustafsson C, Asplund K, Britton M, Norrving B, Olsson B, Marke L. Cost effectiveness of primary stroke prevention in atrial fibrillation: Swedish national perspective. Br Med J 1992; 305: 1457-60.
    CrossrefPubMedGoogle Scholar
  • 27 University of Massachusetts Medical Center. Anticoagulation Clinic Protocols. Worcester, 1993.
    PubMedGoogle Scholar
  • 28 Atrial Fibrillation Investigators, Atrial Fibrillation, Aspirin, Anticoagulation Study; Boston Area Anticoagulation Trial for Atrial Fibrillation Study; Canadian Atrial Fibrillation Anticoagulation Study; Stroke Prevention in Atrial Fibrillation Study; Veterans Affairs Stroke Prevention in Non-rheumatic Atrial Fibrillation Study. Risk factors for stroke and efficacy of antithrombotic therapy in atrial fibrillation. Arch Intern Med 1994; 154: 1449-57.
    CrossrefPubMedGoogle Scholar
  • 29 Brand F.N, Abbott R.D, Kannel W.B, Wolf P.A. Characteristics and prognosis of lone atrial fibrillation: 30-year follow-up in the Framingham Study. J Am Med Assoc 1985; 254: 3449-53.
    CrossrefPubMedGoogle Scholar
  • 30 Naglie I.G, Detsky A.S. Treatment of chronic nonvalvular atrial fibrillation in the elderly: A decision analysis. Med Decis Making 1992; 12: 239-49.
    CrossrefPubMedGoogle Scholar