Digoxin, commonly used to treat heart failure,1,2 has a narrow therapeutic range and is eliminated primarily by the kidney.1 To avoid toxicity, digoxin should be started at ≤0.125 mg/d in patients with chronic kidney disease (CKD) (Table S1).1,2 Reviewing the literature, we found studies of digoxin toxicity in patients with CKD were limited to case reports or focused on patients receiving dialysis (Tables S2-S3). We addressed this knowledge gap by conducting a population-based study of older adults with CKD who were newly prescribed digoxin.