Annals
Established in 1927 by the American College of Physicians
:
Advanced search
 
box Article
 arrow  Table of Contents                
space
 arrow  Full Text of this article Free
space
 arrow  Figures/Tables List
space
box Services
 arrow  Send comment/rapid response letter
space
 arrow  Notify a friend about this article
space
 arrow  Alert me when this article is cited
space
 arrow  Add to Personal Archive
space
 arrow  Download to Citation Manager
space
 arrow  ACP Search                        
space
 arrow  Get Permissions
space
box Google Scholar
 arrow  Search for Related Content
space
box PubMed
Articles in PubMed by Author:
  arrow  Fihn, S. D.
space
 arrow  Related Articles in PubMed
space
 arrow  PubMed Citation
space
 arrow  PubMed
space

ARTICLE

Risk Factors for Complications of Chronic Anticoagulation: A Multicenter Study

right arrow Stephan D. Fihn; Mary McDonell; Donald Martin; Jorja Henikoff; Domokos Vermes; Daniel Kent; Richard H. White, for the Warfarin Optimized Outpatient Follow-up Study Group*

1 April 1993 | Volume 118 Issue 7 | Pages 511-520

Objective: To define risk factors for complications that occur during warfarin therapy.

Design: Retrospective cohort study.

Setting: Five anticoagulation clinics.

Patients: Nine hundred twenty-eight consecutive patients receiving 1103 courses of warfarin.

Main Outcome Measures: Hemorrhagic and thromboembolic complications.

Results: In 1950 patient-years of follow-up, there were 1332 bleeding events (4 were classified as fatal, 31 as life-threatening, 226 as serious, and 1071 as minor). The cumulative incidence of fatal bleeding was 1% at 1 year and 2% at 3 years. The cumulative incidences of first episodes of life-threatening and serious bleeding at 1, 2, 4, and 8 years were 1%, 2%, 5%, and 9% and 12%, 20%, 28%, and 40%, respectively. Of 156 patients who had a serious or life-threatening hemorrhage, 32% suffered a recurrence, typically within 1 year. Independent predictors of a first episode of serious bleeding included a mean prothrombin time ratio (PTR) of 2.0 or more during the course of treatment (relative risk, 3.0; 95% CI, 1.9 to 4.7); recent initiation of warfarin therapy (relative risk during the first 3 months compared with the rest of the first year, the second year, and anytime thereafter, 1.9 [CI, 1.3 to 3.0], 3.0 (CI, 1.8 to 4.8), and 5.9 [CI, 3.8 to 9.3], respectively); variability of the PTR over time (relative risk for the highest compared with the lowest tertile, 1.6 [CI, 1.2 to 2.7]); and the presence of 3 or more comorbid conditions (RR, 1.4 [CI, 1.1 to 2.5]). Age, reason for anticoagulation, use of interfering drugs, and hypertension were not associated with risk for bleeding. The risk for a thromboembolic complication at a PTR of less than 1.3 was 3.6 (CI, 2.1 to 6.4) times higher than at a PTR of 1.3 to 1.5.

Conclusions: The incidence of warfarin-associated bleeding may be reduced by attending to modifiable risk factors (that is, highly variable PTRs and values greater than 2.0), frequent monitoring early in treatment, and careful patient selection. Older age, in and of itself, is not a risk factor.

Author and Article Information
space

From the Health Services Research and Development Field Program, Seattle Veterans Affairs Medical Center, Seattle, Washington. University of California, Davis, Medical Center, Sacramento, California. For current author addresses, see end of text. * See the Appendix for a complete listing of members.
Requests for Reprints: Stephan Fihn, MD, MPH, Section of General Internal Medicine (111M), Seattle Veterans Affairs Medical Center, 1660 South Columbian Way, Seattle, WA 98108.
Grant Support: In part by grants IIR 87-063 and IIR 90-036 from the Health Services and Research Development Program of the Department of Veterans Affairs; by the Center for Outcomes Research in Elderly Persons—A Veterans Affairs Health Services and Research Development Field Program; and by an unrestricted educational grant from Du Pont Pharmaceuticals.




This article has been cited by other articles:


Home page
The Annals of PharmacotherapyHome page
L. M Hynicka, W. D Cahoon Jr, and B. L Bukaveckas
Genetic Testing for Warfarin Therapy Initiation
Ann. Pharmacother., September 1, 2008; 42(9): 1298 - 1303.
[Abstract] [Full Text] [PDF]


Home page
ChestHome page
J. Ansell, J. Hirsh, E. Hylek, A. Jacobson, M. Crowther, and G. Palareti
Pharmacology and Management of the Vitamin K Antagonists: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines (8th Edition)
Chest, June 1, 2008; 133(6_suppl): 160S - 198S.
[Abstract] [Full Text] [PDF]


Home page
ChestHome page
S. Schulman, R. J. Beyth, C. Kearon, and M. N. Levine
Hemorrhagic Complications of Anticoagulant and Thrombolytic Treatment: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines (8th Edition)
Chest, June 1, 2008; 133(6_suppl): 257S - 298S.
[Abstract] [Full Text] [PDF]


Home page
StrokeHome page
G. A. Ford, A. M. Choy, P. Deedwania, D. G. Karalis, C.-J. Lindholm, W. Pluta, L. Frison, S. B. Olsson, and on behalf of the SPORTIF III, V Investigators
Direct Thrombin Inhibition and Stroke Prevention in Elderly Patients With Atrial Fibrillation: Experience From the SPORTIF III and V Trials
Stroke, November 1, 2007; 38(11): 2965 - 2971.
[Abstract] [Full Text] [PDF]


Home page
ANGIOLOGYHome page
R. Bellosta, P. Ferrari, L. Luzzani, C. Carugati, L. Cossu, M. Talarico, and A. Sarcina
Home Therapy With LMWH in Deep Vein Thrombosis: Randomized Study Comparing Single and Double Daily Administrations
Angiology, June 1, 2007; 58(3): 316 - 322.
[Abstract] [PDF]


Home page
CirculationHome page
E. M. Hylek, C. Evans-Molina, C. Shea, L. E. Henault, and S. Regan
Major Hemorrhage and Tolerability of Warfarin in the First Year of Therapy Among Elderly Patients With Atrial Fibrillation
Circulation, May 29, 2007; 115(21): 2689 - 2696.
[Abstract] [Full Text] [PDF]


Home page
CMAJHome page
A. Holbrook, R. Labiris, C. H. Goldsmith, K. Ota, S. Harb, and R. J. Sebaldt
Influence of decision aids on patient preferences for anticoagulant therapy: a randomized trial
Can. Med. Assoc. J., May 22, 2007; 176(11): 1583 - 1587.
[Abstract] [Full Text] [PDF]


Home page
BloodHome page
E. Sconce, P. Avery, H. Wynne, and F. Kamali
Vitamin K supplementation can improve stability of anticoagulation for patients with unexplained variability in response to warfarin
Blood, March 15, 2007; 109(6): 2419 - 2423.
[Abstract] [Full Text] [PDF]


Home page
Am J Health Syst PharmHome page
D. Q. Pham and A. Q. Pham
Interaction potential between cranberry juice and warfarin
Am. J. Health Syst. Pharm., March 1, 2007; 64(5): 490 - 494.
[Abstract] [Full Text] [PDF]


Home page
ChestHome page
T. I. Shireman, J. D. Mahnken, P. A. Howard, T. F. Kresowik, Q. Hou, and E. F. Ellerbeck
Development of a contemporary bleeding risk model for elderly warfarin recipients.
Chest, November 1, 2006; 130(5): 1390 - 1396.
[Abstract] [Full Text] [PDF]


Home page
Arch Intern MedHome page
A. G. Staresinic, C. A. Sorkness, B. M. Goodman, and D. W. Pigarelli
Comparison of outcomes using 2 delivery models of anticoagulation care.
Arch Intern Med, May 8, 2006; 166(9): 997 - 1002.
[Abstract] [Full Text] [PDF]


Home page
ChestHome page
C. van Walraven, A. Jennings, N. Oake, D. Fergusson, and A. J. Forster
Effect of Study Setting on Anticoagulation Control: A Systematic Review and Metaregression
Chest, May 1, 2006; 129(5): 1155 - 1166.
[Abstract] [Full Text] [PDF]


Home page
Arch Intern MedHome page
J. D. Douketis, K. Arneklev, S. Z. Goldhaber, J. Spandorfer, F. Halperin, and J. Horrow
Comparison of Bleeding in Patients With Nonvalvular Atrial Fibrillation Treated With Ximelagatran or Warfarin: Assessment of Incidence, Case-Fatality Rate, Time Course and Sites of Bleeding, and Risk Factors for Bleeding.
Arch Intern Med, April 24, 2006; 166(8): 853 - 859.
[Abstract] [Full Text] [PDF]


Home page
ASH Education BookHome page
B. F. Gage
Pharmacogenetics-Based Coumarin Therapy
Hematology, January 1, 2006; 2006(1): 467 - 473.
[Abstract] [Full Text] [PDF]


Home page
BloodHome page
E. A. Sconce, T. I. Khan, H. A. Wynne, P. Avery, L. Monkhouse, B. P. King, P. Wood, P. Kesteven, A. K. Daly, and F. Kamali
The impact of CYP2C9 and VKORC1 genetic polymorphism and patient characteristics upon warfarin dose requirements: proposal for a new dosing regimen
Blood, October 1, 2005; 106(7): 2329 - 2333.
[Abstract] [Full Text] [PDF]


Home page
ChestHome page
D. Garcia, S. Regan, M. Crowther, R. A. Hughes, and E. M. Hylek
Warfarin Maintenance Dosing Patterns in Clinical Practice: Implications for Safer Anticoagulation in the Elderly Population
Chest, June 1, 2005; 127(6): 2049 - 2056.
[Abstract] [Full Text] [PDF]


Home page
Am J Health Syst PharmHome page
D. L. Singla and G. B. Morrill
Warfarin maintenance dosages in the very elderly
Am. J. Health Syst. Pharm., May 15, 2005; 62(10): 1062 - 1066.
[Abstract] [Full Text] [PDF]


Home page
Eur Heart J SupplHome page
S. Schulman and R. J. Beyth
Risk of bleeding with long-term antithrombotic therapy in atrial fibrillation
Eur. Heart J. Suppl., May 1, 2005; 7(suppl_C): C34 - C40.
[Abstract] [Full Text] [PDF]


Home page
BloodHome page
G. D'Andrea, R. L. D'Ambrosio, P. Di Perna, M. Chetta, R. Santacroce, V. Brancaccio, E. Grandone, and M. Margaglione
A polymorphism in the VKORC1 gene is associated with an interindividual variability in the dose-anticoagulant effect of warfarin
Blood, January 15, 2005; 105(2): 645 - 649.
[Abstract] [Full Text] [PDF]


Home page
ANN INTERN MEDHome page
B. Menendez-Jandula, J. C. Souto, A. Oliver, I. Montserrat, M. Quintana, I. Gich, X. Bonfill, and J. Fontcuberta
Comparing Self-Management of Oral Anticoagulant Therapy with Clinic Management: A Randomized Trial
Ann Intern Med, January 4, 2005; 142(1): 1 - 10.
[Abstract] [Full Text] [PDF]


Home page
CLIN APPL THROMB HEMOSTHome page
G. F. Pineo and R. D. Hull
Low-Molecular-Weight Heparin for the Treatment of Venous Thromboembolism in the Elderly
Clinical and Applied Thrombosis/Hemostasis, January 1, 2005; 11(1): 15 - 23.
[Abstract] [PDF]


Home page
J. Clin. Pathol.Home page
J P Hanley
Warfarin reversal
J. Clin. Pathol., November 1, 2004; 57(11): 1132 - 1139.
[Abstract] [Full Text] [PDF]


Home page
Arch Intern MedHome page
N. Kucher, S. Connolly, J. A. Beckman, L. H. Cheng, K. V. Tsilimingras, J. Fanikos, and S. Z. Goldhaber
International Normalized Ratio Increase Before Warfarin-Associated Hemorrhage: Brief and Subtle
Arch Intern Med, October 25, 2004; 164(19): 2176 - 2179.
[Abstract] [Full Text] [PDF]


Home page
Arch Intern MedHome page
N. Kagansky, H. Knobler, E. Rimon, Z. Ozer, and S. Levy
Safety of Anticoagulation Therapy in Well-informed Older Patients
Arch Intern Med, October 11, 2004; 164(18): 2044 - 2050.
[Abstract] [Full Text] [PDF]


Home page
StrokeHome page
T. I. Shireman, P. A. Howard, T. F. Kresowik, and E. F. Ellerbeck
Combined Anticoagulant-Antiplatelet Use and Major Bleeding Events in Elderly Atrial Fibrillation Patients
Stroke, October 1, 2004; 35(10): 2362 - 2367.
[Abstract] [Full Text] [PDF]


Home page
ChestHome page
J. Ansell, J. Hirsh, L. Poller, H. Bussey, A. Jacobson, and E. Hylek
The Pharmacology and Management of the Vitamin K Antagonists: The Seventh ACCP Conference on Antithrombotic and Thrombolytic Therapy
Chest, September 1, 2004; 126(3_suppl): 204S - 233S.
[Abstract] [Full Text] [PDF]


Home page
ChestHome page
M. N. Levine, G. Raskob, R. J. Beyth, C. Kearon, and S. Schulman
Hemorrhagic Complications of Anticoagulant Treatment: The Seventh ACCP Conference on Antithrombotic and Thrombolytic Therapy
Chest, September 1, 2004; 126(3_suppl): 287S - 310S.
[Abstract] [Full Text] [PDF]


Home page
Arch Intern MedHome page
S. Koo, N. Kucher, P. L. Nguyen, J. Fanikos, P. W. Marks, and S. Z. Goldhaber
The Effect of Excessive Anticoagulation on Mortality and Morbidity in Hospitalized Patients With Anticoagulant-Related Major Hemorrhage
Arch Intern Med, July 26, 2004; 164(14): 1557 - 1560.
[Abstract] [Full Text] [PDF]


Home page
Ann. Thorac. Surg.Home page
M. A. Quader, P. M. McCarthy, A. M. Gillinov, J. M. Alster, D. M. Cosgrove III, B. W. Lytle, and E. H. Blackstone
Does preoperative atrial fibrillation reduce survival after coronary artery bypass grafting?
Ann. Thorac. Surg., May 1, 2004; 77(5): 1514 - 1524.
[Abstract] [Full Text] [PDF]


Home page
Arch Intern MedHome page
M. Man-Son-Hing and A. Laupacis
Anticoagulant-Related Bleeding Risk in Older Persons: Unfounded Fears?--Reply
Arch Intern Med, January 12, 2004; 164(1): 107 - 107.
[Full Text] [PDF]


Home page
NEJMHome page
R. J. Folkeringa, T. N.H. Dinh, H. J.G.M. Crijns, E. F. Epstein, I. Natarajan, C. J. Boos, E. M. Hylek, A. S. Go, and D. E. Singer
Oral Anticoagulation and Stroke in Atrial Fibrillation
N. Engl. J. Med., December 11, 2003; 349(24): 2360 - 2361.
[Full Text] [PDF]


Home page
Arch Intern MedHome page
A. P. A. Gadisseur, W. G. M. Breukink-Engbers, F. J. M. van der Meer, A. M. H. van den Besselaar, A. Sturk, and F. R. Rosendaal
Comparison of the Quality of Oral Anticoagulant Therapy Through Patient Self-management and Management by Specialized Anticoagulation Clinics in the Netherlands: A Randomized Clinical Trial
Arch Intern Med, November 24, 2003; 163(21): 2639 - 2646.
[Abstract] [Full Text] [PDF]


Home page
CMAJHome page
S. J.-A. Wilson, P. S. Wells, M. J. Kovacs, G. M. Lewis, J. Martin, E. Burton, and D. R. Anderson
Comparing the quality of oral anticoagulant management by anticoagulation clinics and by family physicians: a randomized controlled trial
Can. Med. Assoc. J., August 19, 2003; 169(4): 293 - 298.
[Abstract] [Full Text] [PDF]


Home page
J. Clin. Pathol.Home page
T P Oppenkowski, E T Murray, H Sandhar, and D A Fitzmaurice
External quality assessment for warfarin dosing using computerised decision support software
J. Clin. Pathol., August 1, 2003; 56(8): 605 - 607.
[Abstract] [Full Text] [PDF]


Home page
Arch Intern MedHome page
M. Man-Son-Hing and A. Laupacis
Anticoagulant-Related Bleeding in Older Persons With Atrial Fibrillation: Physicians' Fears Often Unfounded
Arch Intern Med, July 14, 2003; 163(13): 1580 - 1586.
[Abstract] [Full Text] [PDF]


Home page
NeurologyHome page
E. E. Smith, J. Rosand, K. A. Knudsen, E. M. Hylek, and S. M. Greenberg
Leukoaraiosis is associated with warfarin-related hemorrhage following ischemic stroke
Neurology, July 23, 2002; 59(2): 193 - 197.
[Abstract] [Full Text] [PDF]


Home page
BloodHome page
J. Zarza, J. Hermida, R. Montes, I. Alberca, M. L. Lopez, and E. Rocha
Leu208Val and Ile181Leu variants of cytochrome P450 CYP2C9 are not related to the acenocoumarol dose requirement in a Spanish population
Blood, June 28, 2002; 100(2): 734 - 735.
[Full Text] [PDF]


Home page
JAMAHome page
M. K. Higashi, D. L. Veenstra, L. M. Kondo, A. K. Wittkowsky, S. L. Srinouanprachanh, F. M. Farin, and A. E. Rettie
Association Between CYP2C9 Genetic Variants and Anticoagulation-Related Outcomes During Warfarin Therapy
JAMA, April 3, 2002; 287(13): 1690 - 1698.
[Abstract] [Full Text] [PDF]


Home page
Arch Intern MedHome page
M. Man-Son-Hing and A. Laupacis
Balancing the Risks of Stroke and Upper Gastrointestinal Tract Bleeding in Older Patients With Atrial Fibrillation
Arch Intern Med, March 11, 2002; 162(5): 541 - 550.
[Abstract] [Full Text] [PDF]


Home page
Eur Heart J SupplHome page
H. Voller, C. Dovifat, and J. Glatz
Home management of anticoagulation
Eur. Heart J. Suppl., December 1, 2001; 3(suppl_Q): Q44 - Q49.
[Abstract] [PDF]


Home page
Arch Intern MedHome page
D. McCormick, J. H. Gurwitz, R. J. Goldberg, R. Becker, J. P. Tate, A. Elwell, and M. J. Radford
Prevalence and Quality of Warfarin Use for Patients With Atrial Fibrillation in the Long-term Care Setting
Arch Intern Med, November 12, 2001; 161(20): 2458 - 2463.
[Abstract] [Full Text] [PDF]


Home page
StrokeHome page
C. Wehinger, C. Stollberger, T. Langer, B. Schneider, and J. Finsterer
Evaluation of Risk Factors for Stroke/Embolism and of Complications Due to Anticoagulant Therapy in Atrial Fibrillation
Stroke, October 1, 2001; 32(10): 2246 - 2252.
[Abstract] [Full Text] [PDF]


Home page
ANN INTERN MEDHome page
E. M. Hylek, S. Regan, A. S. Go, R. A. Hughes, D. E. Singer, and S. J. Skates
Clinical Predictors of Prolonged Delay in Return of the International Normalized Ratio to within the Therapeutic Range after Excessive Anticoagulation with Warfarin
Ann Intern Med, September 18, 2001; 135(6): 393 - 400.
[Abstract] [Full Text] [PDF]


Home page
NEJMHome page
M. O. McCarron, J. A.R. Nicoll, M. J. O'Leary, R. J.L. Waugh, A. I. Qureshi, and D. F. Hanley
Spontaneous Intracerebral Hemorrhage
N. Engl. J. Med., September 6, 2001; 345(10): 769 - 770.
[Full Text] [PDF]


Home page
Ann Rheum DisHome page
G Castellino, M J Cuadrado, T Godfrey, M A Khamashta, and G R V Hughes
Characteristics of patients with antiphospholipid syndrome with major bleeding after oral anticoagulant treatment
Ann Rheum Dis, May 1, 2001; 60(5): 527 - 530.
[Abstract] [Full Text] [PDF]


Home page
ChestHome page
K. Ananthasubramaniam, J. N. Beattie, H. S. Rosman, V. Jayam, and S. Borzak
How Safely and for How Long Can Warfarin Therapy Be Withheld in Prosthetic Heart Valve Patients Hospitalized With a Major Hemorrhage?
Chest, February 1, 2001; 119(2): 478 - 484.
[Abstract] [Full Text] [PDF]


Home page
ChestHome page
J. Ansell, J. Hirsh, J. Dalen, H. Bussey, D. Anderson, L. Poller, A. Jacobson, D. Deykin, and D. Matchar
Managing Oral Anticoagulant Therapy
Chest, January 1, 2001; 119(1_suppl): 22S - 38S.
[Full Text] [PDF]


Home page
ChestHome page
M. N. Levine, G. Raskob, S. Landefeld, and C. Kearon
Hemorrhagic Complications of Anticoagulant Treatment
Chest, January 1, 2001; 119(1_suppl): 108S - 121S.
[Full Text] [PDF]


Home page
ANN INTERN MEDHome page
R. J. Beyth, L. Quinn, and C. S. Landefeld
A Multicomponent Intervention To Prevent Major Bleeding Complications in Older Patients Receiving Warfarin: A Randomized, Controlled Trial
Ann Intern Med, November 7, 2000; 133(9): 687 - 695.
[Abstract] [Full Text] [PDF]


Home page
Arch Intern MedHome page
S. K. Kajubi
Additional Monitoring Tools to Improve the Quality of Anticoagulation Management
Arch Intern Med, October 23, 2000; 160(19): 3006 - 3006.
[Full Text] [PDF]


Home page
J Am Coll CardiolHome page
K. Hammermeister, G. K. Sethi, W. G. Henderson, F. L. Grover, C. Oprian, and S. H. Rahimtoola
Outcomes 15 years after valve replacement with a mechanical versus a bioprosthetic valve: final report of the Veterans Affairs randomized trial
J. Am. Coll. Cardiol., October 1, 2000; 36(4): 1152 - 1158.
[Abstract] [Full Text] [PDF]


Home page
Arch Intern MedHome page
D. A. Fitzmaurice, F. D. R. Hobbs, E. T. Murray, R. L. Holder, T. F. Allan, and P. E. Rose
Oral Anticoagulation Management in Primary Care With the Use of Computerized Decision Support and Near-Patient Testing: A Randomized, Controlled Trial
Arch Intern Med, August 14, 2000; 160(15): 2343 - 2348.
[Abstract] [Full Text] [PDF]


Home page
QJMHome page
J. Berwaerts and J. Webster
Analysis of risk factors involved in oral-anticoagulant-related intracranial haemorrhages
QJM, August 1, 2000; 93(8): 513 - 521.
[Abstract] [Full Text] [PDF]


Home page
Arch Intern MedHome page
E. M. Hylek, Y. Chang, S. J. Skates, R. A. Hughes, and D. E. Singer
Prospective Study of the Outcomes of Ambulatory Patients With Excessive Warfarin Anticoagulation
Arch Intern Med, June 12, 2000; 160(11): 1612 - 1617.
[Abstract] [Full Text] [PDF]


Home page
ASH Education BookHome page
J. E. Ansell, J. I. Weitz, and A. J. Comerota
Advances in Therapy and the Management of Antithrombotic Drugs for Venous Thromboembolism
Hematology, January 1, 2000; 2000(1): 266 - 284.
[Abstract] [Full Text] [PDF]


Home page
NeurologyHome page
J. W. Gorter
Major bleeding during anticoagulation after cerebral ischemia: Patterns and risk factors
Neurology, October 1, 1999; 53(6): 1319 - 1319.
[Abstract] [Full Text]


Home page
LupusHome page
E. Cretel, P. Cacoub, D. L. Thi Huong, A. Gompel, Z. Amoura, and J.-C. Piette
Massive ovarian haemorrhage complicating oral anticoagulation in the Antiphospholipid Syndrome: a report of three cases
Lupus, July 1, 1999; 8(6): 482 - 485.
[Abstract] [PDF]


Home page
Arch Intern MedHome page
P. M. M. Kuijer, B. A. Hutten, M. H. Prins, and H. R. Buller
Prediction of the Risk of Bleeding During Anticoagulant Treatment for Venous Thromboembolism
Arch Intern Med, March 8, 1999; 159(5): 457 - 460.
[Abstract] [Full Text] [PDF]


Home page
ANN INTERN MEDHome page
G. W. Petty, R. D. Brown Jr., J. P. Whisnant, J. D. Sicks, W. M. O'Fallon, and D. O. Wiebers
Frequency of Major Complications of Aspirin, Warfarin, and Intravenous Heparin for Secondary Stroke Prevention: A Population-Based Study
Ann Intern Med, January 5, 1999; 130(1): 14 - 22.