Medication Adherence is a Mediator of the Relationship Between Ethnicity and Event-Free Survival in Patients With Heart Failure

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. Objective To determine whether medication adherence is a mediator of the relationship between ethnicity and event-free survival in patients with HF. Methods Medication adherence was monitored longitudinally in 135 HF patients using the Medication Event Monitoring System (MEMS). Events (ED 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 were conducted to determine whether medication adherence mediated the relationship between ethnicity and event-free survival. Results 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). Conclusion 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.

Medication Adherence to Specific Drug Classes in Chronic Heart Failure

“…Previous studies have monitored only 1 drug with MEMS, assuming that adherence reflects an individual behavior. 4,11,[13][14][15] However, our results do not support this approach, and some recent studies using pharmacy refill data also suggested that it is not enough to monitor 1 drug to understand patient behavior. Gislason et al (2007) have reported different adherence estimates for inhibitors of the renin angiotensin system (RAS; 79%), beta blockers (65%), and spironolactone (56%).…”

“…Several studies have quantified medication adherence in patients with HF using electronic-monitoring devices, such as the Medication Event Monitoring System (MEMS). 4,11,[13][14][15] MEMS has been reported as a valid, reliable, and precise instrument, 16 providing detailed information about the medication-taking behavior that is not possible with other methods. Most previous studies of patients with HF have monitored only 1 drug with MEMS, arguing that monitoring 1 drug reflects the whole adherence behavior.…”

“…Most previous studies of patients with HF have monitored only 1 drug with MEMS, arguing that monitoring 1 drug reflects the whole adherence behavior. 4,11,[13][14][15] However, this argument is not evidence based, and recent studies using different methods to measure adherence in patients with HF have reported differences in adherence depending on the drug class analyzed. 10,17 We, therefore, conducted this study of patients with HF to quantify medication adherence to ACEI, beta blockers, and loop diuretics using MEMS and to assess the degree of agreement in adherence to different drug classes.…”

Social Determinants of Risk and Outcomes for Cardiovascular Disease

“…Nonwhite patients are significantly more likely to be nonadherent to statins and antihypertensive medications, [235][236][237] and medication nonadherence has been shown to mediate the relationship between ethnicity and CVD outcomes. 238 Of interest, a comparison between black and white individuals with hypertension in terms of preferences for behavior change revealed that both exercise and fruit and vegetable consumption were the preferred changes and did not differ by race. However, implementation of these behaviors differed by race, with a majority of whites, but not blacks, engaged in exercise.…”

The Pharmacist Role in Predicting and Improving Medication Adherence in Heart Failure Patients

“…31,33,34 Perceived social support was measured using the Multidimensional Perceived Social Support Scale, 35 which is a self-administered, 12-item Likert scale to determine the patient's beliefs about social support from family, friends, or significant others.…”