Warfarin use in nursing home residents: results from the 2004 national nursing home survey.

Background: Practice guidelines recommend anticoagulation therapy with warfarin for stroke prevention in patients with atrial fibrillation (AF). Despite this, warfarin is underused in older adults.

Objective: The purpose of this study was to determine the prevalence of AF in nursing home (NH) residents and the use of warfarin or other antiplatelet medications in NH residents with AF who have indications for and no contraindications against warfarin use. The secondary objective was to determine the factors associated with warfarin use in NH residents with AF.

Methods: Cross-sectional analysis of prescription and resident data files from the 2004 National Nursing Home Survey was performed. Residents with a diagnosis of AF were identified using International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) codes, and prescriptions of warfarin and antiplatelet medications were identified using Long-Term Care Drug Database System (LTCDDS) codes. Resident characteristics, stroke risk factors, and potential bleeding risk factors significant at P < 0.10 in χ(2) analyses were entered in the final multiple logistic regression model to determine the factors associated with warfarin use.

Results: From 13,507 NH residents, 1904 (14%) had a diagnosis of AF and 1767 (13%) had a diagnosis of AF with indications for and no contraindications against warfarin use. Of these 1767 residents, 537 (30%) were prescribed warfarin, and of the remaining 1230 residents who were not prescribed warfarin, 283 (23%) received either aspirin or clopidogrel. Thus, of 1767 residents with AF, with indications for and no contraindications to warfarin use, 947 (54%) residents did not receive any antithrombotic therapy in the form of warfarin, aspirin, clopidogrel, or a combination of these medications. Factors that were significantly associated with increased odds of receiving warfarin were congestive heart failure, previous stroke or transient ischemic attack, deep vein thrombosis or peripheral embolus, valvular heart disease, and total number of medications ≥ 6. Factors that were significantly associated with reduced odds of receiving warfarin were nonwhite race, history of gastrointestinal bleeding, and use of antiplatelets (ie, clopidogrel).

Conclusions: AF is common in NH residents, and more than half of the residents with AF who had indications for and no contraindications against warfarin use were not prescribed either warfarin or antiplatelets, such as aspirin or clopidogrel, suggesting that antithrombotic therapy may be underused in NH residents with AF.