Table 2.

Groupings of variables (Block) used in models

Block	Variables
1	Epogen (EPO) dose during exposure period
2	Block 1 & age, sex, race
3	Block 2 & baseline hemoglobin, ferritin, and index TSAT
4 (Fully adjusted model)	Block 3 & pneumonia, vascular access infection, or sepsis in past 6 months; any infection in past month; most recent vascular access is catheter; vintage; baseline albumin; baseline EPO dose; baseline iron dose; history of diabetes, stroke, myocardial infarction, chronic obstructive pulmonary disease, cancer, or gasterointestinal bleeding in past 6 months; number of hospital days in past month, and body mass index
5 (Sensitivity analysis)	Block 4 & reason for ESRD (Diabetes,glomerulonephritis, hypertension, other); history of the following in the past 6 months: heart problems (combining ischemic heart disease, other heart, peripheral vascular disease, coronary artery bypass grafting/coronary artery stenting/percutaneous coronary angioplasty), hypertension, rheumatic heart disease, psychiatric problems, transfusion, autoimmune disorder, blood loss anemia, pulmonary circulation disease, ulcer, liver disease, other neurological problem, substance use.; year; geographic region; Medicaid eligibility