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The Cost Effectiveness of Anticoagulation Management Services for Patients with Atrial Fibrillation and at High Risk of Stroke in the US

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Abstract

Background

Anticoagulation therapy with warfarin is widely considered the standard of care for stoke prophylaxis in patients with atrial fibrillation who are at high risk of stroke. Community-based studies in the US have reported that the effectiveness of anticoagulation varies by management approach and that patients receiving warfarin have international normalised ratio (INR) values within the target therapeutic range less than half the time.

Objective

To estimate the lifetime societal costs and health benefits of warfarin therapy to prevent strokes, specifically in elderly patients (mean age 70 years) with atrial fibrillation who are at high risk of stroke, when anticoagulation is managed through usual care versus anticoagulation management services, where dedicated anticoagulation professionals (e.g. physician or pharmacist) monitor and oversee patients.

Methods

Semi-Markov decision model with a 30-day cycle length and 10-year time horizon (to reflect the mean life expectancy of the study population). Univariate sensitivity analyses and Bayesian second-order multivariate probabilistic sensitivity analysis using Monte Carlo simulation were performed.

Outcomes measures were costs and QALYs. Most of the probability and outcome estimates included were derived from the recent SPORTIF (Stroke Prevention using ORal Thrombin Inhibitor in atrial Fibrillation) V trial. Utility values were derived from a large, nationally representative sample of individuals in the Medical Expenditure Panel Survey and were adjusted for age, sex, race, ethnicity, income, education and co-morbidity. Resource utilisation was based on experience at the University Medicine Group Practice Anticoagulation Clinic (University of Colorado, Denver, CO, USA) and costs ($US; 2004 values) included were for warfarin and aspirin (acetylsalicylic acid) use and those associated with major bleeding, treatment of primary events, routine INR and biochemistry monitoring, ECGs, and clinic visits. Costs and outcomes were discounted by 3% per annum.

Results

The anticoagulation management service improved effectiveness by 0.057 (95% credible interval 0, 0.36) QALYs and reduced costs by $US2100 (95% credible interval −$US19 800, $US300) [2004 values] compared with usual care. Results were sensitive to the extent of the increase in risk of primary events (all strokes and systemic embolic events attributable to usual care, but were robust to variation in other input variables). The anticoagulation management service was the dominant strategy in 91% of Monte Carlo simulations.

Conclusion

The anticoagulation management service appears to cost less and provide greater effectiveness than usual care. To enhance stroke prophylaxis among high-risk patients with atrial fibrillation, physicians and Medicare plans may wish to consider augmenting ‘usual care’ by the addition of patient-monitoring technology strategies such as formally organised anticoagulation monitoring programmes.

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Acknowledgements

This research was supported by an unrestricted grant from The Bristol Myers Squibb Company. The authors had complete autonomy in all aspects of study design and conduct and manuscript preparation. The authors have no conflicts of interest that are directly relevant to the content of this study.

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Authors and Affiliations

  1. Pharmaceutical Outcomes Research Program, Department of Clinical Pharmacy, School of Pharmacy, University of Colorado at Denver and Health Sciences Center, 4200 East Ninth Avenue, Box C238, Denver, Colorado, 80262, USA

    Patrick W. Sullivan

  2. Department of Clinical and Experimental Pharmacology, School of Medicine, University of Adelaide, Adelaide, South Australia, Australia

    Thomas W. Arant

  3. Department of Clinical Research, George Washington University School of Medicine & Health Sciences, Washington, USA

    Thomas W. Arant

  4. Department of Clinical Pharmacy, School of Pharmacy, University of Colorado at Denver and Health Sciences Center, Denver, Colorado, USA

    Samuel L. Ellis & Heather Ulrich

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  1. Patrick W. Sullivan
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Correspondence to Patrick W. Sullivan.

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Sullivan, P.W., Arant, T.W., Ellis, S.L. et al. The Cost Effectiveness of Anticoagulation Management Services for Patients with Atrial Fibrillation and at High Risk of Stroke in the US. Pharmacoeconomics 24, 1021–1033 (2006). https://doi.org/10.2165/00019053-200624100-00009

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