Table 1.

Covariates used to estimate propensity scores for initial dialysis modality

a Assessed using enrollment in Medicaid or the New Jersey Pharmaceutical Assistance for the Aged and Disabled program within the year before first renal replacement therapy as a proxy for lower socioeconomic status.
b All covariates were assessed within the year before first renal replacement therapy. Covariates were binary (absent/present) unless specifically noted otherwise.
c Late referral, first nephrologist visit ≤90 d before first renal replacement therapy; early referral, first nephrologist visit >90 d before first renal replacement therapy.
d Cardiology, endocrinology-diabetology, gastroenterology-hepatology, hematooncology, infectious diseases, pulmonology, and rheumatology.
Demographic covariatesComorbiditiesb
• age, age2, age3• hypertension
• race (white/black/other)• diabetes
• gender• coronary artery disease (CAD)
• socioeconomic status (SES)a• congestive heart failure
• cerebrovascular disease (CVD)
Renal underlying diseaseb• peripheral vascular disease (PVD)
• acute (glomerulo)nephritis• malignancy
• polycystic kidney disease• gastrointestinal erosion/ulcer (without surgery)
• diabetic nephropathy
• hypertensive kidney disease• abdominal hernia (with or without surgical repair)
• chronic pyelonephritis
• obstructive nephropathy• major abdominal surgery
• renovascular disease• diverticulosis of colon
• miscellaneous• severe liver disease
• chronic renal disease not otherwise specified• obesity
• Chronic obstructive pulmonary disease
• HIV+/AIDS
Health care utilizationb• dementia
• late versus early nephrologist referralc• depression
• number of nephrologist visits (0 to 3; 4 to 9; 10+)• alcohol or substance abuse
• presence of primary care visits• other mental disease
• presence of medical subspecialist visitsdInteraction terms
• presence of surgical consultations• age * gender, race (2 terms), SES
• number of hospital days (0; 1 to 7; 8 to 28; 29+)• race * gender (2 terms), SES (2 terms)
• presence of nursing home stay• diabetes * CVD, CAD, PVD