Appendix Table 1.

Qualifying episodes of warfarin use.

Criterion	Medicaid Episodes (persons)	Medicare Episodes (persons)
1. Filled prescription for warfarin during study period for a patient 30 years of age or older. For Tennessee Medicaid, the patient must be enrolled for the prior year in a category with full pharmacy benefits. For the Medicare 5% sample, the patient must be enrolled in Medicare parts A, B, and D but not in part C (Medicare Advantage) in the month the warfarin prescription was filled and in the preceding 12 calendar months.	92,856 (83,807)	118,832 (116,016)
2. New treatment episode. No other filled prescription for any oral anticoagulant in the past year.	64,015 (58,503)	46,868 (46,021)
3. At least one outpatient visit (excluding laboratory claims) and one filled prescription(excluding the warfarin prescription) in the past year to assure that patients have had regular contact with medical care.	61,618 (56,471)	46,096 (45,273)
4. No end-stage renal disease in the past year, in order to exclude patients with use of warfarin for dialysis.	59,157 (54,297)	44,108 (43,335)
5. No serious upper GI illness in the past year predisposing to frequent GI bleeding or altering the pathology of peptic ulcer disease. This excludes persons who may have frequent care for bleeding from other causes, such as esophageal varices or gastrointestinal cancer.	57,178 (52,516)	41,963 (41,243)
6. No prior bleeding-related hospitalization in the past year, defined as a hospital stay meeting the study endpoint definition. We excluded these patients because it would be difficult to determine if subsequent bleeding hospitalizations represented a new event or continued care for bleeding that began prior to warfarin treatment. The numbers of exclusions for each type of bleeding hospitalization are shown in the columns.	56,114 (51,584)	41,316 (40,618)
a. Upper gastrointestinal	336 (301)	164 (161)
b. Other gastrointestinal	417 (362)	313 (300)
c. Other bleed.	311 (269)	170 (164)