Outcomes associated with warfarin use in older patients with heart failure and atrial fibrillation and a cardiovascular implantable electronic device: findings from the ADHERE registry linked to Medicare claims.
BACKGROUND
Warfarin use and associated outcomes in patients with heart failure and atrial fibrillation and a cardiovascular implantable electronic device have not been described previously.


OBJECTIVE
We hypothesized that warfarin is underused and is associated with lower risks of mortality, thromboembolic events, and myocardial infarction.


METHODS
Using data from a clinical registry linked with Medicare claims, we examined warfarin use at discharge and 30-day and 1-year Kaplan-Meier estimates of all-cause mortality and cumulative incidence rates of mortality, thromboembolic events, myocardial infarction, and bleeding events in patients 65 years or older, with a history of atrial fibrillation and a cardiovascular implantable electronic device admitted with heart failure between 2001 and 2006, who were naïve to anticoagulation therapy at admission. We compared outcomes between patients who were or were not prescribed warfarin at discharge and tested associations between treatment and outcomes.


RESULTS
Of 2586 eligible patients in 252 hospitals, 2049 were discharged without a prescription for warfarin. At 1 year, the group discharged without warfarin had a higher mortality rate after discharge (37.4% vs 28.8%; P < 0.001) but similar rates of thromboembolism, myocardial infarction, and bleeding events. After adjustment, treatment with warfarin was associated with lower risk of all-cause death 1 year after discharge (hazard ratio: 0.76, 95% confidence interval: 0.63-0.92).


CONCLUSIONS
Among older patients with heart failure and atrial fibrillation and a cardiovascular implantable electronic device, 4 of 5 were discharged without a prescription for warfarin. Warfarin nonuse was associated with a higher risk of death 1 year after discharge. Clin. Cardiol. 2011 DOI: 10.1002/clc.22064 Damon M. Seils, MA, Duke University, assisted with manuscript preparation. Mr. Seils did not receive compensation for his assistance apart from his employment at the institution where the study was conducted. This study was supported by a research agreement between Duke University and Janssen Pharmaceuticals. The authors have no other funding, financial relationships, or conflicts of interest to disclose.
Duke Clinical Research Institute, Duke University School of Medicine, Durham, NC, USA.
Paul L
PL
Hess
Melissa A
MA
Greiner
Gregg C
GC
Fonarow
Winslow
W
Klaskala
Roger M
RM
Mills
Soko
S
Setoguchi
Sana M
SM
Al-Khatib
Adrian F
AF
Hernandez
Lesley H
LH
Curtis
D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000925:Anticoagulants / Q000009:adverse effects / Q000627:therapeutic use*; D001281:Atrial Fibrillation / Q000150:complications / Q000188:drug therapy* / Q000401:mortality; D002304:Cardiac Pacing, Artificial / Q000009:adverse effects / Q000401:mortality; D058406:Cardiac Resynchronization Therapy; D058409:Cardiac Resynchronization Therapy Devices; D016009:Chi-Square Distribution; D017147:Defibrillators, Implantable; D004554:Electric Countershock / Q000009:adverse effects / Q000295:instrumentation / Q000401:mortality; D005260:Female; D006333:Heart Failure / Q000150:complications / Q000401:mortality / Q000628:therapy*; D006470:Hemorrhage / Q000139:chemically induced / Q000401:mortality; D006801:Humans; D015994:Incidence; D053208:Kaplan-Meier Estimate; D016015:Logistic Models; D008297:Male; D006278:Medicare; D009203:Myocardial Infarction / Q000401:mortality / Q000517:prevention & control; D010138:Pacemaker, Artificial; D010351:Patient Discharge; D016016:Proportional Hazards Models; D012042:Registries; D018570:Risk Assessment; D012307:Risk Factors; D013923:Thromboembolism / Q000401:mortality / Q000517:prevention & control; D013997:Time Factors; D016896:Treatment Outcome; D014481:United States; D014859:Warfarin / Q000009:adverse effects / Q000627:therapeutic use*
D000925:Anticoagulants; D014859:Warfarin