Flow diagram demonstrating selection of study cohort. BMI, body mass index; VA, Veterans Affairs. aPatients were also excluded if the following occurred in January 2011: death, kidney transplantation, change in modality away from in-center hemodialysis (e.g., home hemodialysis or peritoneal dialysis), uncertain/recovered function, loss to follow-up, withdrawal from dialysis, or loss of Part D coverage, which precluded ascertainment of exposure status as of February 2011.