Factors associated with non-adherence to therapy with warfarin in a population of chronic heart failure patients.
BACKGROUND
Adherence to heart failure therapy is important in reducing morbidity and mortality over the course of the disease process. The aim of this study was to examine factors associated with non-adherence to warfarin in chronic heart failure patients.


METHODS
Eighty patients receiving warfarin therapy in 2002 were included. Adherence was defined as maintenance of international normalized ratio (INR) between 2 and 3.5 and keeping scheduled appointments for INR checks at least 75% of the time. Clinical variables examined included age, gender, race, insurance, left ventricular ejection fraction (LVEF), etiology, New York heart association (NYHA) class, comorbidities, smoking, and alcohol use.


RESULTS
Of 80 patients studied, 59 were male with mean age ( +/- standard deviation) 52 +/- 13 years, 24 had ischemic etiology with mean LVEF of 24% +/- 9%. Non-adherence was associated with tobacco use, odds ratio of 6.5 (p <0.01). Ischemic etiology was associated with adherence, odds ratio of 4.5 (p <0.01). Non-adherent patients were more likely to be insured with Medicare/Medicaid (p = 0.04) and have better NYHA class (p = 0.04). Adherence positively correlated with older age and lower LVEF, and negatively correlated with number of hospitalizations (p<0.01 for all). In a multiple regression model, patients with improvement in LVEF had decreased adherence over the year (p<0.01).


CONCLUSIONS
The profile of heart failure patients who demonstrated non-adherence to warfarin therapy included younger age, nonischemic etiology, better NYHA class, smoking, insurance with Medicare/Medicaid and improved LVEF over the study. Measures targeting these patients may result in improved adherence to other pharmacologic treatments of heart failure.
Pamboukian
Salpy V
SV
The University of Alabama at Birmingham, Birmingham, Alabama, USA. svpam@uab.edu
Nisar
Imran
I
Patel
Sheetal
S
Gu
Liping
L
McLeod
Mary
M
Costanzo
Maria Rosa
MR
Heroux
Alain
A
D000925:Anticoagulants / Q000627:therapeutic use*; D005260:Female; D005500:Follow-Up Studies; D006333:Heart Failure / Q000188:drug therapy* / Q000453:epidemiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D009017:Morbidity; D011379:Prognosis; D012189:Retrospective Studies; D012307:Risk Factors; D015996:Survival Rate; D016312:Treatment Refusal / Q000706:statistics & numerical data*; D014481:United States / Q000453:epidemiology; D014859:Warfarin / Q000627:therapeutic use*
D000925:Anticoagulants; D014859:Warfarin