CKD: chronic kidney disease, BB: beta-blocker, ACEi: ace inhibitor, CAD: coronary artery disease, DM: diabetes mellitus, CHF: congestive heart failure, HTN: hypertension, and ASA: aspirin. Shah: metaregression done on patients who only had atrial fibrillation. Shah: metaregression done on patients who had both atrial fibrillation and congestive heart failure Allen P: prevalent digoxin group; Allen I: incident digoxin group.