There is substantial published evidence that warfarin reduces the risk of stroke in patients with atrial fibrillation (AF). However, the current literature suggests that not all patients who could benefit from warfarin receive the drug.
To evaluate patient-related demographic and clinical factors that could influence warfarin use or other anticoagulant use in hospitalized patients with AF.
Retrospective observational study using claims data from the Wolters Kluwer Pharma Solutions Hospital Patient Level Database, evaluating characteristics of patients hospitalized in the US between 1 November 2003 and 31 October 2004.
The study included 44 193 patients aged ≥40 years who were hospitalized between 1 November 2003 and 31 October 2004 and had a diagnosis of AF during hospitalization (AF did not need to be the cause of hospitalization).
Use of warfarin or other anticoagulants (unfractionated heparin [UFH] or low-molecular-weight heparin [LMWH]) was evaluated.
Main Outcome Measures
A logistic regression model was used to identify factors associated with warfarin use, international normalized ratio (INR) monitoring, or the use of anticoagulants (UFH or LMWH).
In this analysis of hospitalized patients with AF in the real-world setting, about 56% of patients received anticoagulation therapy with warfarin. Elderly patients aged ≥75 years were less likely to be treated with warfarin than younger patients, but patients between the ages of 60 and 74 years were more likely to use warfarin than their younger counterparts. Except for patients with congestive heart failure or vascular malformation, patients with other bleeding risk factors (hepatic disease, renal disease, aspirin use, and fractures) were significantly less likely to receive warfarin than those without these risk factors. CHADS2 scores for stroke risk of 2 and 3 were associated with a significantly higher likelihood of warfarin treatment than scores of 0 or 1. Patients admitted through a routine admission (an outpatient department) were significantly more likely to be prescribed warfarin than patients admitted through an emergency room. Patients aged ≥75 years and aspirin users were more likely to have their INR monitored during hospitalization. With respect to other anticoagulant use, females and older patients (≥65 years) were less likely to use UFH or LMWH, and patients with renal disease or vascular malformation and those receiving aspirin were more likely to use UFH or LMWH than patients without these conditions/not receiving aspirin. Patients admitted through the emergency room were more likely to receive an anticoagulant than patients admitted through an outpatient department, an inpatient transfer, or any other source.
Older age, female sex, and certain risk factors for bleeding, including hepatic disease, renal disease, aspirin use, and fractures, were associated with a lower likelihood of warfarin treatment, while a higher stroke risk (as indicated by CHADS2 scores) was associated with a higher likelihood of warfarin treatment, in hospitalized patients with a diagnosis of AF. The likelihood of INR being monitored increased for patients aged ≥75 years and for aspirin users. Older patients and female patients were less likely to be prescribed other anticoagulants (UFH or LMWH) also.
This is a preview of subscription content, log in to check access.
Buy single article
Instant access to the full article PDF.
Price includes VAT for USA
Miyasaka Y, Barnes ME, Gersh BJ, et al. Secular trends in incidence of atrial fibrillation in Olmsted County, Minnesota, 1980 to 2000, and implications on the projections for future prevalence. Circulation 2006; 114: 119–25.
Feinberg WM, Blackshear JL, Laupacis A, et al. Prevalence, age distribution, and gender of patients with atrial fibrillation: analysis and implications. Arch Intern Med 1995; 155: 469–73.
Go AS, Hylek EM, Phillips KA, et al. Prevalence of diagnosed atrial fibrillation in adults: national implications for rhythm management and stroke prevention. The AnTicoagulation and Risk Factors In Atrial Fibrillation (ATRIA) study. JAMA 2001; 285: 2370–5.
Benjamin EJ, Wolf PA, D’Agostino RB, et al. Impact of atrial fibrillation on the risk of death: the Framingham Heart Study. Circulation 1998; 98: 946–52.
Singer DE. A 60-year-old woman with atrial fibrillation. JAMA 2003; 290: 2182–9.
Hart RG, Pearce LA, Aguilar MI. Meta-analysis: antithrombotic therapy to prevent stroke in patients who have nonvalvular atrial fibrillation. Ann Intern Med 2007; 146: 857–67.
Fuster V, Ryden LE, Cannom DS, et al. ACC/AHA/ESC 2006 guidelines 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 European Society of Cardiology Committee for Practice Guidelines (Writing Committee to Revise the 2001 Guidelines for the Management of Patients With Atrial Fibrillation): developed in collaboration with the European Heart Rhythm Association and the Heart Rhythm Society. Circulation 2006; 114: e257–354.
Akhtar W, Reeves WC, Movahed A. Indications for anticoagulation in atrial fibrillation. Am Fam Physician 1998; 58: 130–6.
Gage BF, Waterman AD, Shannon W, et al. Validation of clinical classification schemes for predicting stroke: results from the National Registry of Atrial Fibrillation. JAMA 2001; 285: 2864–70.
The Boston Area Anticoagulation Trial for Atrial Fibrillation Investigators. The effect of low-dose warfarin on the risk of stroke in patients with non-rheumatic atrial fibrillation. N Engl J Med 1990; 323: 1505–11.
Stroke Prevention in Atrial Fibrillation Study: final results. Circulation 1991; 84: 527–39.
EAFT (European Atrial Fibrillation Trial) Study Group. Secondary prevention in non-rheumatic atrial fibrillation after transient ischaemic attack or minor stroke. Lancet 1993; 342: 1255–62.
Connolly SJ, Laupacis A, Gent M, et al. Canadian Atrial Fibrillation Anti-coagulation (CAFA) study. J Am Coll Cardiol 1991; 18: 349–55.
Ezekowitz MD, Bridgers SL, James KE, et al. Warfarin in the prevention of stroke associated with nonrheumatic atrial fibrillation. Veterans Affairs Stroke Prevention in Nonrheumatic Atrial Fibrillation Investigators. N Engl J Med 1992; 327: 1406–12.
Petersen P, Boysen G, Godtfredsen J, et al. Placebo-controlled, randomised trial of warfarin and aspirin for prevention of thromboembolic complications in chronic atrial fibrillation. The Copenhagen AFASAK study. Lancet 1989; 1: 175–9.
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: 2685–92.
Bungard TJ, Ghali WA, Teo KK, et al. Why do patients with atrial fibrillation not receive warfarin? Arch Intern Med 2000; 160: 41–6.
Gurwitz JH, Monette J, Rochon PA, et al. Atrial fibrillation and stroke prevention with warfarin in the long-term care setting. Arch Intern Med 1997; 157: 978–84.
McCormick D, Gurwitz JH, Goldberg RJ, et al. Long-term anticoagulation therapy for atrial fibrillation in elderly patients: efficacy, risk, and current patterns of use. J Thromb Thrombolysis 1999; 7: 157–63.
Mendelson G, Aronow WS. Underutilization of warfarin in older persons with chronic nonvalvular atrial fibrillation at high risk for developing stroke. J Am Geriatr Soc 1998; 46: 1423–4.
Smith NL, Psaty BM, Furberg CD, et al. Temporal trends in the use of anticoagulants among older adults with atrial fibrillation. Arch Intern Med 1999; 159: 1574–8.
Stafford RS, Singer DE. National patterns of warfarin use in atrial fibrillation. Arch Intern Med 1996; 156: 2537–41.
Stafford RS, Singer DE. Recent national patterns of warfarin use in atrial fibrillation. Circulation 1998; 97: 1231–3.
McGlynn EA, Asch SM, Adams J, et al. The quality of health care delivered to adults in the United States. N Engl J Med 2003; 348: 2635–45.
Cohen N, Almoznino-Sarafian D, Alon I, et al. Warfarin for stroke prevention still underused in atrial fibrillation: patterns of omission. Stroke 2000; 31: 1217–22.
Dasta JF, McLaughlin TP, Mody SH, et al. Daily cost of an intensive care unit day: the contribution of mechanical ventilation. Crit Care Med 2005; 33: 1266–71.
Hart RG, Benavente O, McBride R, et al. Antithrombotic therapy to prevent stroke in patients with atrial fibrillation: a meta-analysis. Ann Intern Med 1999; 131:492–501.
Reynolds MW, Fahrbach K, Hauch O, et al. Warfarin anticoagulation and outcomes in patients with atrial fibrillation: a systematic review and metaanalysis. Chest 2004; 126: 1938–45.
Singer DE, Albers GW, Dalen JE, et al. Antithrombotic therapy in atrial fibrillation: American College of Chest Physicians evidence-based clinical practice guidelines (8th edition). Chest 2008; 133 Suppl. 6: 546S–92S.
Goldstein LB, Adams R, Alberts MJ, et al. Primary prevention of ischemic stroke: a guideline from the American Heart Association/American Stroke Association Stroke Council: cosponsored by the Atherosclerotic Peripheral Vascular Disease Interdisciplinary Working Group; Cardiovascular Nursing Council; Clinical Cardiology Council; Nutrition, Physical Activity, and Metabolism Council; and the Quality of Care and Outcomes Research Interdisciplinary Working Group: the American Academy of Neurology affirms the value of this guideline. Stroke 2006; 37: 1583–633.
Snow V, Weiss KB, LeFevre M, et al. Management of newly detected atrial fibrillation: a clinical practice guideline from the American Academy of Family Physicians and the American College of Physicians. Ann Intern Med 2003; 139: 1009–17.
Antani MR, Beyth RJ, Covinsky KE, et al. Failure to prescribe warfarin to patients with nonrheumatic atrial fibrillation. J Gen Intern Med 1996; 11: 713–20.
Sudlow M, Rodgers H, Kenny RA, et al. Population based study of use of anticoagulants among patients with atrial fibrillation in the community. BMJ 1997; 314: 1529–30.
Whittle J, Wickenheiser L, Venditti LN. Is warfarin underused in the treatment of elderly persons with atrial fibrillation? Arch Intern Med 1997; 157: 441–5.
Choudhry NK, Soumerai SB, Normand SL, et al. Warfarin prescribing in atrial fibrillation: the impact of physician, patient, and hospital characteristics. Am J Med 2006; 119: 607–15.
Fitzmaurice DA, Blann AD, Lip GYH. Bleeding risks of antithrombotic therapy. In: Lip GYH, Blann AD, editors. ABC of antithrombotic therapy. London: BMJ Publishing Group, 2003: 5–8.
Marine JE, Goldhaber SZ. Controversies surrounding long-term anti-coagulation of very elderly patients in atrial fibrillation. Chest 1998; 113: 1115–8.
American Stroke Association. Stroke risk factors [online]. Available from URL: http://www.americanheart.org/presenter.jhtml?identifier=4716 [Accessed 2007 Jan 21].
Frost L, Johnsen SP, Pedersen L, et al. Atrial fibrillation or flutter and stroke: a Danish population-based study of the effectiveness of oral anticoagulation in clinical practice. J Intern Med 2002; 252: 64–9.
McCormick D, Gurwitz JH, Goldberg RJ, et al. Prevalence and quality of warfarin use for patients with atrial fibrillation in the long-term care setting. Arch Intern Med 2001; 161: 2458–63.
Beyth RJ, Antani MR, Covinsky KE, et al. Why isn’t warfarin prescribed to patients with nonrheumatic atrial fibrillation? J Gen Intern Med 1996; 11:721–8.
Bradley BC, Perdue KS, Tisdel KA, et al. Frequency of anticoagulation for atrial fibrillation and reasons for its non-use at a Veterans Affairs medical center. Am J Cardiol 2000; 85: 568–72.
Funding for this research was provided by GlaxoSmithKline. We wish to thank Yingjia Shen for assistance with statistical analysis and Catherine Rees for editorial assistance with the manuscript. Dr Smith is an employee of Wolters Kluwer Pharma Solutions and Dr Agarwal was an employee of Wolters Kluwer Pharma Solutions (formerly Wolters Kluwer Health Pharma Solutions Business Unit) at the time the study was conducted. Dr Bennett is an employee of GlaxoSmithKline.
About this article
Cite this article
Agarwal, S., Bennett, D. & Smith, D.J. Predictors of Warfarin Use in Atrial Fibrillation Patients in the Inpatient Setting. Am J Cardiovasc Drugs 10, 37–48 (2010). https://doi.org/10.2165/11318870-000000000-00000
- Atrial Fibrillation
- International Normalize Ratio
- Anticoagulant Therapy
- Stroke Risk