THE IMPACT OF PHARMACOTHERAPY ON LONG-TERM SURVIVAL AND RISK OF RE-HOSPITALIZATION FOR STROKE AFTER HOSPITALIZATION FOR ATRIAL FIBRILLATION

Abstract

While several drugs have shown survival benefits in coronary artery disease (CAD), their impacts on mortality and hospitalization for adverse cardiac outcomes have been less well evaluated in patients with atrial fibrillation (AF). The objectives of this study were to evaluate the impact of several drugs on long-term all-cause mortality and risk of hospitalization for stroke or transient ischemic attack (TIA), in patients hospitalized for AF. Using Québec provincial linked health administrative databases, we conducted a retrospective cohort study of all patients aged ≥65 years hospitalized in Québec for a primary diagnosis of AF between 1998-2002 who were also subscribed to the provincial prescription drug insurance plan. We excluded patients who died during the index hospitalization, and patients who had undergone cardiothoracic surgery 30 days before AF diagnosis. The primary endpoint was all-cause mortality; the secondary endpoint was hospitalization for stroke/TIA. We used multivariate regression Cox proportional hazards to determine the independent risks associated with the use of beta-blockers, calcium channel blockers (CCB), diuretics, statins, ACE-I/ARBs, warfarin, digoxin, and antiarrhythmic drugs for both endpoints. A total of 10,158 patients (mean age of 76.5 years, 59% females) were included in the analysis. For the primary endpoint, the median follow-up period was 6.5 years (IQR 2.8, 10.4). At baseline, 65.6% of patients were hypertensive and 19.8% of patients had diabetes mellitus. There was a history of prior stroke or TIA in 10.1% of patients. A history of CAD was present in 53.5% of patients hospitalized for AF, of which 29.3% had prior MI. The use of beta-blockers, statins, warfarin and antiarrythmics were all associated with lower all-cause mortality (Table 1), while diuretics and digoxin were associated with increased mortality. Warfarin was the only drug associated with decreased risk of hospitalization for stroke/TIA. Our data suggests that in patients ≥65 years hospitalized for AF, beta-blockers, statins, antiarrythmics and warfarin were associated with long-term survival benefit while the opposite association was shown for diuretics and digoxin. As expected, warfarin use was associated with decreased risk of hospitalization for stroke/TIA. Future randomized controlled studies are needed to elucidate the effects of these drug classes on cardiovascular outcomes in patients with AF.