Adherence to Cardiovascular Medications: Lessons Learned and Future Directions

Approximately 50% of patients with cardiovascular disease and/or its major risk factors have poor adherence to their prescribed medications. Finding novel methods to help patients improve their adherence to existing evidence-based cardiovascular drug therapies has enormous potential to improve health outcomes while potentially reducing health care costs. The goal of this report is to provide a review of the current understanding of adherence to cardiovascular medications from the point of view of prescribing clinicians and cardiovascular researchers. Key topics addressed include: 1) definitions of medication adherence; 2) prevalence and impact of non-adherence; 3) methods for assessing medication adherence; 4) reasons for poor adherence; and 5) approaches to improving adherence to cardiovascular medications. For each of these topics, the report seeks to identify important gaps in knowledge and opportunities for advancing the field of cardiovascular adherence research

Guidelines, Inertia, and Judgment

There is a general agreement among healthcare providers that hypertension should be controlled, by either lifestyle improvement or antihypertensive drug treatment, for prevention of cardiovascular and renal disease. This agreement has been articulated in published guidelines and widely disseminated in other formats. Control has been defined as reduction of pressure below thresholds of 140/90 mm Hg and, for those with diabetes mellitus or chronic renal disease, 130/80 mm Hg. Population surveys in the United States estimate that control of hypertension remains suboptimal, with ≈50% continuing to have uncontrolled hypertension

How Should We Treat Depression in Patients with Cardiovascular Disease?

Among patients with cardiovascular disease (CVD), depression is highly prevalent and is associated with worse cardiovascular prognosis and lower quality of life. Treatments for depression in CVD patients produce modest, but clinically significant reductions in depressive symptoms and show promise for improving cardiovascular prognosis. While tricyclics should generally be avoided, antidepressants from multiple other classes appear to be safe in cardiac patients. A strategy of engaging patients in choosing medications or psychotherapy and then intensifying treatment to therapeutic goal appears to be more effective at reducing depression than single mode interventions. Recommendations for screening all CVD patients for depression may be premature given increased costs associated with screening and gaps in knowledge about the risk-benefit ratio of depression treatment in mild and moderately depressed patients

Understanding Minority Patients’ Beliefs About Hypertension to Reduce Gaps in Communication Between Patients and Clinicians

The authors’ objective was to gain a better understanding of minority patients’ beliefs about hypertension and to use this understanding to develop a model to explain gaps in communication between patients and clinicians. Eighty-eight hypertensive black and Latino adults from 4 inner-city primary care clinics participated in focus groups to elucidate views on hypertension. Participants believed that hypertension was a serious illness in need of treatment. Participants’ diverged from the medical model in their beliefs about the time-course of hypertension (believed hypertension was intermittent); causes of hypertension (believed stress, racism, pollution, and poverty were the important causes); symptoms of hypertension (believed hypertension was primarily present when symptomatic); and treatments for hypertension (preferred alternative treatments that reduced stress over prescription medications). Participants distrusted clinicians who prioritized medications that did not directly address their understanding of the causes or symptoms of hypertension. Patients’ models of understanding chronic asymptomatic illnesses such as hypertension challenge the legitimacy of lifelong, pill-centered treatment. Listening to patients’ beliefs about hypertension may increase trust, improve communication, and encourage better self-management of hypertension

Stroke survivors’ endorsement of a “stress belief model” of stroke prevention predicts control of risk factors for recurrent stroke

Perceptions that stress causes and stress-reduction controls hypertension have been associated with poorer blood pressure (BP) control in hypertension populations. The current study investigated these “stress-model perceptions” in stroke survivors regarding prevention of recurrent stroke and the influence of these perceptions on patients’ stroke risk factor control. Stroke and transient ischemic attack survivors (N = 600) participated in an in-person interview in which they were asked about their beliefs regarding control of future stroke; BP and cholesterol were measured directly after the interview. Counter to expectations, patients who endorsed a “stress-model” but not a “medication-model” of stroke prevention were in better control of their stroke risk factors (BP and cholesterol) than those who endorsed a medication-model but not a stress-model of stroke prevention (OR for poor control = .54, Wald statistic = 6.07, p = .01). This result was not explained by between group differences in patients’ reported medication adherence. The results have implications for theory and practice, regarding the role of stress belief models and acute cardiac events, compared to chronic hypertension

Antihypertensive Drug Class and Adherence: An Electronic Monitoring Study

Background: Medication adherence is essential to optimizing blood pressure (BP) control. Prior research has demonstrated differences in pharmacy refill patterns according to antihypertensive drug class. No prior study has assessed the association between drug class and day-to-day adherence. Methods: Between 2011 and 2014, we enrolled a convenience sample of 149 patients with persistently uncontrolled hypertension from two inner-city clinics and concurrently measured adherence of up to four antihypertensive medications using electronic pillboxes during the interval between two primary care visits. The main outcome was mean percent of days adherent to each drug. Mixed effects regression analyses were used to assess the association between drug class and adherence adjusting for age, gender, race, ethnicity, education, health insurance, coronary artery disease, heart failure, chronic kidney disease, diabetes, number of medications, days monitored, and dosing frequency. Results: The mean age was 64 years; 72% women, 75% Hispanic, 88% prescribed ≥1 BP medication. In unadjusted analyses, adherence was lower for beta-blockers (70.9%) compared to angiotensin receptor blocking agents (75.0%, P = 0.11), diuretics (75.9%, P < 0.001), calcium channel blockers (77.6%, P < 0.001) and angiotensin-converting enzyme inhibitors (78.0%, P < 0.0001). In the adjusted analysis, only dosing frequency (P = 0.0001) but not drug class (P = 0.71) was associated with medication adherence. Conclusions: Antihypertensive drug class was not associated with electronically measured adherence after accounting for dosing frequency amongst patients with uncontrolled hypertension. Low adherence to beta-blockers may have been due to the common practice of prescribing multiple daily dosing. Providers may consider using once daily formulations to optimize adherence and should assess adherence among all treated patients with uncontrolled hypertension. Key words: blood pressure drug class hypertension medication adherence

Predictors of Nonadherence to Statins: A Systematic Review and Meta-Analysis

BACKGROUND: Nonadherence to statins limits the benefits of this common drug class. Individual studies assessing predictors of nonadherence have produced inconsistent results. OBJECTIVE: To identify reliable predictors of nonadherence to statins through systematic review and meta-analysis. METHODS: Multiple databases, including MEDLINE, EMBASE, and PsycINFO, were searched (from inception through February 2009) to identify studies that evaluated predictors of nonadherence to statins. Studies were selected using a priori defined criteria, and each study was reviewed by 2 authors who abstracted data on study characteristics and outcomes. Relative risks were then pooled, using an inverse-variance weighted random-effects model. RESULTS: Twenty-two cohort studies met inclusion criteria. Age had a U-shaped association with adherence; the oldest (≥70 years) and youngest (<50 years) subjects had lower adherence than the middle-aged (50–69 years) subjects. Women and patients with lower incomes were more likely to be nonadherent than were men (odds of nonadherence 1.07; 95% CI 1.04 to 1.11) and those with higher incomes (odds of nonadherence 1.18; 95% CI 1.10 to 1.28), respectively. A history of cardiovascular disease predicted better adherence to statins (odds of nonadherence 0.68; 95% CI 0.66 to 0.78). Similarly, a diagnosis of hypertension or diabetes was associated with better adherence. Although there were too few studies for quantitative pooling, increased testing of lipid levels and lower out-of-pocket costs appeared to be associated with better adherence. There was substantial (I2 range 68.7–96.3%) heterogeneity between studies across factors. CONCLUSIONS: Several sociodemographic, medical, and health-care utilization characteristics are associated with statin nonadherence. These factors may be useful guides for targeting statin adherence interventions

Objectively Measured Adherence to Physical Activity Guidelines After Acute Coronary Syndrome

Physical activity is a cornerstone of secondary prevention after acute coronary syndromes (ACS). Guidelines strongly recommend that post-ACS patients achieve ≥30 min of moderate aerobic activity such as brisk walking on at least 5 days per week within 2 weeks of discharge (1). Yet, little is known about the extent to which post-ACS patients are meeting physical activity guidelines. Prior studies assessing physical activity after ACS were limited by reliance on self-reports (2). The purpose of this study was to use an objective measure of physical activity to describe the proportion of ACS patients following physical activity recommendations in the high-risk post-discharge period. Between 2009 and 2012, we enrolled patients hospitalized for myocardial infarction (MI) or unstable angina into the PULSE (Prescription Use, Lifestyle, and Stress Evaluation) study. Some patients participated in an ancillary study in which they were provided with an Actical accelerometer (Philips Respironics, Bend, Oregon) at or soon after discharge (3). Patients were asked to continuously wear the device on their nondominant wrist and to return the device 1 month later. All patients provided informed consent. The institutional review board of Columbia University Medical Center approved the study

Medication adherence and visit-to-visit variability of systolic blood pressure in African Americans with chronic kidney disease in the AASK trial

Lower adherence to antihypertensive medications may increase visit-to-visit variability of blood pressure (VVV of BP), a risk factor for cardiovascular events and death. We used data from the African American Study of Kidney Disease and Hypertension (AASK) trial to examine whether lower medication adherence is associated with higher systolic VVV of BP in African Americans with hypertensive chronic kidney disease (CKD). Determinants of VVV of BP were also explored. AASK participants (n=988) were categorized by self-report or pill count as having perfect (100%), moderately high (75–99%), moderately low (50–74%) or low ( < 50%) proportion of study visits with high medication adherence over a 1-year follow-up period. We used multinomial logistic regression to examine determinants of medication adherence, and multivariable-adjusted linear regression to examine the association between medication adherence and systolic VVV of BP, defined as the coefficient of variation or the average real variability (ARV). Participants with lower self-reported adherence were generally younger and had a higher prevalence of comorbid conditions. Compared with perfect adherence, moderately high, moderately low and low adherence was associated with 0.65% (±0.31%), 0.99% (±0.31%) and 1.29% (±0.32%) higher systolic VVV of BP (defined as the coefficient of variation) in fully adjusted models. Results were qualitatively similar when using ARV or when using pill counts as the measure of adherence. Lower medication adherence is associated with higher systolic VVV of BP in African Americans with hypertensive CKD; efforts to improve medication adherence in this population may reduce systolic VVV of BP

The Psychosocial Context Impacts Medication Adherence After Acute Coronary Syndrome

Background Depression is associated with poor adherence to medications and worse prognosis in patients with acute coronary syndrome (ACS). Purpose To determine whether cognitive, behavioral, and/or psychosocial vulnerabilities for depression explain the association between depression and medication adherence among ACS patients. Methods One hundred sixty-nine ACS patients who agreed to have their aspirin adherence measured using an electronic pill bottle for 3 months were enrolled within 1 week of hospitalization. Linear regression was used to determine whether depression vulnerabilities predicted aspirin adherence after adjustment for depressive symptoms, demographics, and comorbidity. Results Of the depression vulnerabilities, only role transitions (beta = −3.32; P = 0.02) and interpersonal conflict (beta -3.78; P = 0.03) predicted poor adherence. Depression vulnerabilities did not mediate the association between depressive symptoms and medication adherence. Conclusions Key elements of the psychosocial context preceding the ACS including major role transitions and conflict with close contacts place ACS patients at increased risk for poor medication adherence independent of depressive symptoms