Medication Adherence is a Mediator of the Relationship Between Ethnicity and Event-Free Survival in Patients With Heart Failure
Received 9 December 2008; received in revised form 5 October 2009; accepted 6 October 2009. published online 11 December 2009.
Abstract
Background
Rehospitalization rates are higher in African American than Caucasian patients with heart failure (HF). The reasons for the disparity in outcomes between African Americans and Caucasians may relate to differences in medication adherence. To determine whether medication adherence is a mediator of the relationship between ethnicity and event-free survival in patients with HF.
Methods and Results
Medication adherence was monitored longitudinally in 135 HF patients using the Medication Event Monitoring System. Events (emergency department visits for HF exacerbation, HF and cardiac rehospitalization, and all-cause mortality) were obtained by interview and hospital data base review. A series of regression models and survival analyses was conducted to determine whether medication adherence mediated the relationship between ethnicity and event-free survival. Event-free survival was significantly worse in African Americans than Caucasians. Ethnicity was a predictor of medication adherence (P=.011). African Americans were 2.57 times more likely to experience an event than Caucasians (P=.026). Ethnicity was not a predictor of event-free survival after entering medication adherence in the model (P=.06).
Conclusions
Medication adherence was a mediator of the relationship between ethnicity and event-free survival in this sample. Interventions designed to reduce barriers to medication adherence may decrease the disparity in outcomes.
1University of Kentucky, College of Nursing, Lexington, KY
2DoD Blast Injury Research Program Coordinating Office, U.S. Army Research and Material Command, Ft. Detrick, MD
3Indiana University, School of Nursing, Indianapolis, IN
Reprint requests: Jia-Rong Wu, PhD, RN, University of Kentucky, College of Nursing, 509 CON Building, 760 Rose Street, Lexington, KY 40536-0232. Phone: (859) 257-6921; Fax: (859) 257-0554.
Supported by funding from the Philips Medical-American Association of Critical Care Nurses Outcomes Grant, University of Kentucky General Clinical Research Center (M01RR02602), American Heart Association Great River Affiliate Post-doctoral Fellowship to Jia-Rong Wu, grant #R01 NR008567 from the National Institute of Nursing Research and a Center grant to the University of Kentucky, College of Nursing from NIH, NINR, 1P20NR010679.
The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institute of Nursing Research or the National Institutes of Health. The opinions or assertions contained herein are the private views of the authors and are not to be construed as official or as reflecting the views of the Department of the Air Force or the Department of Defense.
ABSTRACT