Table 3

Comparison of Patient Selection Methods in Prior Studies Examining Warfarin Utilization in AF Patients
Study Period	Author	Setting	Patient Selection for AF based on	Patient Population Size	Warfarin Utilization %	"Warfarin Candidates" not on Warfarin %	Method of determining Warfarin Utilization

1995–1998	Weisbord et al.¹³	VA	Medical Chart review	1289	65	3.5	Medical Chart reviewed by physicians for documented contraindication
1996–1997	Go et al.¹¹	Large HMO	ICD-9-CM code	13428	55	37.9	Pharmacy database, Outpatient INR, ICD for "Coumadin Therapy"
1997–1998	McCormick et al.¹²	Long term Care Facility	Medical Chart reviewed for EKG diagnosis or documentation by physician	429	42	32	Warfarin prescriptions, INR, Physician Notes
2000–2002	Waldo et al.⁹	Teaching, community and VA hospitals	ICD-9-CM code	945	54	22	ICD-9 & Medical chart review
2000–2005	Darkow et al.⁷	HMO	ICD-9-CM code	12539	39	61	Unable to obtain
2001–2003	Hylek et al.⁸	Urban teaching hospital	Electronic medical chart review and ECG verified AF	405	51	2	Electronic medical chart review for physician cited reasons for warfain non-use
2004–2005	Our Study	Single Tertiary Care Hospital	Medical Chart review and physician confirmation of AF by EKG	364	54	7.1	Medical chart reviewed by physicians for documented contraindication

Srivastava et al. Thrombosis Journal 2008 6:6 doi:10.1186/1477-9560-6-6