Does synchronizing initiation of therapy affect adherence to concomitant use of antihypertensive and lipid-lowering therapy?

Improving medication adherence in cardiovascular disease

Non-adherence to medication is a global health problem with far-reaching individual-level and population-level consequences but remains unappreciated and under-addressed in the clinical setting. With increasing comorbidity and polypharmacy as well as an ageing population, cardiovascular disease and medication non-adherence are likely to become increasingly prevalent. Multiple methods for detecting non-adherence exist but are imperfect, and, despite emerging technology, a gold standard remains elusive. Non-adherence to medication is dynamic and often has multiple causes, particularly in the context of cardiovascular disease, which tends to require lifelong medication to control symptoms and risk factors in order to prevent disease progression. In this Review, we identify the causes of medication non-adherence and summarize interventions that have been proven in randomized clinical trials to be effective in improving adherence. Practical solutions and areas for future research are also proposed.

Evaluating Adherence to Concomitant Diabetes, Hypertension, and Hyperlipidemia Treatments and Cardiovascular Outcomes Among Elderly Patients Using Marginal Structural Modeling

INTRODUCTION

Comorbid diabetes, hypertension, and hyperlipidemia is associated with an adverse effect on cardiovascular (CV) outcomes. Adherence to concurrent anti-diabetics, anti-hypertensives, and lipid-lowering therapies is essential to achieve therapeutic benefits.

AIM

The objective was to evaluate the association between adherence to concomitant oral antidiabetics, statins, and RAS antagonists (triple therapy) and CV outcomes, among elderly patients using marginal structural modeling (MSM).

METHODS

A retrospective study was conducted among patients on concurrent triple therapy from January 2016 until December 2019. Adherence to concurrent triple therapy was measured every 6 months using proportion of days covered (PDC) to determine the different adherence groups. CV outcomes were also measured every 6 months. A MSM controlling for baseline covariates and time-varying confounders affected by prior adherence was conducted to evaluate the association between adherence and CV outcomes. A sub-analysis was conducted among patients with prior CV events to evaluate the association between adherence to triple therapy and CV outcomes using MSMs.

RESULTS

The final cohort comprised of 7433 patients. The MSM model revealed no significant associations between adherence to triple/double therapies and cardiovascular outcomes. For sub-analysis, 471 patients with a prior CV event were identified. Results of the sub-analysis revealed no significant associations between adherence to triple/double therapies and CV outcomes among patients with prior CV events.

CONCLUSION

Future studies should evaluate the association with longer follow-up periods.

Prevalence and predictors of medication non-adherence among people living with multimorbidity: a systematic review and meta-analysis

OBJECTIVES

This systematic review aimed to describe medication non-adherence among people living with multimorbidity according to the current literature, and synthesise predictors of non-adherence in this population.

METHODS

A systematic review was conducted according to the Preferred Reporting Items for Systematic reviews and Meta-Analyses. PubMed, EMBASE, CINAHL and PsycINFO were searched for relevant articles published in English language between January 2009 and April 2019. Quantitative studies reporting medication non-adherence and/or predictors of non-adherence among people with two or more chronic conditions were included in the review. A meta-analysis was conducted with a subgroup of studies that used an inclusive definition of multimorbidity to recruit participants, rather than seeking people with specific conditions. Remaining studies reporting prevalence and predictors of non-adherence were narratively synthesised.

RESULTS

The database search produced 10 998 records and a further 75 were identified through other sources. Following full-text screening, 178 studies were included in the review. The range of reported non-adherence differed by measurement method, at 76.5% for self-report, 69.4% for pharmacy data, and 44.1% for electronic monitoring. A meta-analysis was conducted with eight studies (n=8949) that used an inclusive definition of multimorbidity to recruit participants. The pooled prevalence of non-adherence was 42.6% (95% CI: 34.0 - 51.3%, k=8, I²=97%, p<0.01). The overall range of non-adherence was 7.0%-83.5%. Frequently reported correlates of non-adherence included previous non-adherence and treatment-related beliefs.

CONCLUSIONS

The review identified a heterogeneous literature in terms of conditions studied, and definitions and measures of non-adherence used. Results suggest that future attempts to improve adherence among people with multimorbidity should determine for which conditions individuals require most support. The variable levels of medication non-adherence highlight the need for more attention to be paid by healthcare providers to the impact of multimorbidity on chronic disease self-management.

PROSPERO REGISTRATION NUMBER

CRD42019133849.

Appointment-based models: A comparison of three model designs in a large chain community pharmacy setting

OBJECTIVES

To compare the effects of 3 different appointment-based model (ABM) designs on medication adherence and medication use outcomes controlling for patient and pharmacy characteristics.

METHODS

This study was a retrospective cohort analysis in a large grocery store chain from January 1, 2012, to October 31, 2015. A total of 500 comparison and 613 intervention patients in 3 different model designs were analyzed. The outcome measures were proportion of days covered for selected medication classes, number of fills, administered vaccinations, number of trips, statin use in persons with diabetes, use of high-risk medications in older adults, and medication therapy for persons with asthma.

RESULTS

After adjusting for relevant covariates, the authors found that all of the ABM designs significantly increased the number of fills after enrollment. Model designs 1 and 3 also significantly reduced the number of trips after enrollment: 4.5 fewer trips (95% CI -5.3 to -3.8; P < 0.05) for model 1 and 1.9 fewer trips (95% CI -3 to -0.9; P < 0.05) for model 3. Models 1 and 3 increased the percentage of patients considered to be adherent for diabetes medications and increased the number of vaccinations patients received. Models 1 and 2 significantly increased the percentage of patients considered to be adherent for statins. No model design was significantly associated with statin use in diabetes, high-risk medication use in older adults, nor percentage of patients considered to be adherent for the hypertension measure.

CONCLUSION

All of the ABM designs were effective at increasing the number of fills after enrollment. This paralleled an increase in percentage of patients considered to be adherent to diabetes and statin therapies after enrollment. Models that included face-to-face delivery of the appointment and telephonic synchronization, or face-to-face delivery for all components, increased the number of vaccinations that patients received after enrollment and significantly reduced the number of trips a patient made to the pharmacy.

Medication Synchronization Programs Improve Adherence To Cardiovascular Medications And Health Care Use

Medication synchronization programs based in pharmacies simplify the refill process by enabling patients to pick up all of their medications on a single visit. This can be especially important for improving medication adherence in patients with complex chronic diseases. We evaluated the impact of two synchronization programs on adherence, cardiovascular events, and resource use among Medicare beneficiaries treated between 2011 and 2014 for two or more chronic conditions-at least one of which was hypertension, hyperlipidemia, or diabetes. Among nearly 23,000 patients matched by propensity score, the mean proportion of days covered (a measure of medication adherence) for the control group of patients without a synchronization program was 0.84 compared to 0.87 for synchronized patients-a gain of 3 percentage points. Adherence improvement in synchronized versus control patients was three times greater in patients with low baseline adherence, compared to those with higher baseline adherence. Rates of hospitalization and emergency department visits and rates of outpatient visits were 9 percent and 3 percent lower in the synchronized group compared to the control group, respectively, while cardiovascular event rates were similar. Synchronization programs were associated with improved adherence for patients with cardiovascular disease, especially those with low baseline adherence.

Development of a medication synchronization common language for community pharmacies

OBJECTIVES

To develop a common language for the medication synchronization process in community pharmacies.

METHODS

A systematic and iterative process was used to create and refine a common language for medication synchronization. First, a review of all available medication synchronization-related documents was completed. Second, a systematic scoping literature review was conducted to determine what core components of medication synchronization have been implemented by community pharmacies. Third, semistructured interviews were conducted with community pharmacists and key stakeholders to identify principles and successful practices. Findings from the document review, systematic scoping review, and semistructured interviews were integrated to develop a medication synchronization common language. Finally, researchers and key stakeholders refined the initial draft by means of a systematic process.

RESULTS

This process generated a medication synchronization common language that includes common language for the philosophy and values of medication synchronization. This profile also includes descriptions of core components with activities to be conducted for each of the identified 5 core components. The 5 core components are: 1) identification and enrollment of patients; 2) completion of a medication review and patient assessment; 3) alignment of medication refills; 4) preparation for medication delivery; and 5) delivery of medication and other services.

CONCLUSION

The development of a common language for medication synchronization will allow for the promotion of consistency in implementation and operation of these programs across community pharmacies. Consistency in implementation will allow for better interpretation of patient outcomes such as adherence and other clinical measures.

Persistence with antihypertensives in uncomplicated treatment-naïve very elderly patients: a nationwide population-based study

BACKGROUND

Limited studies have evaluated the medication-taking behavior in very elderly hypertensive patients. The aim of this study was to evaluate the persistence and adherence with antihypertensive agents in treatment-naïve patients, along with other related factors, according to age.

METHODS

Adult (19-64 years), elderly (65-79 years), and very elderly (≥80 years) uncomplicated hypertensive patients starting antihypertensive monotherapy were identified from the National Health Insurance claims database. The first-year treatment persistence and adherence rates measured using the medication possession ratio were assessed and compared in these three age cohorts.

RESULTS

After propensity score matching, three age cohorts with 6689 patients each were assembled from 228,925 uncomplicated hypertensive patients who began antihypertensive monotherapy in 2012. The treatment persistence and adherence rates over the first year were the lowest in the very elderly (59.5% and 62.8%, respectively) and highest in the elderly (65.2% and 67.9%, respectively) patients among the three age cohorts (p < 0.001). The adjusted risk for treatment non-persistence was significantly higher in the very elderly (adjusted hazard ratio, 1.20; 95% confidence interval, 1.13-1.27) compared with the elderly. Having more comorbidities, being a beneficiary of medical aid, and having a diagnosis of dementia were unique positive predictors for treatment persistence in the very elderly, along with common predictors such as female sex, dyslipidemia, and an initially chosen antihypertensive therapeutic class other than beta blockers and thiazide diuretics.

CONCLUSIONS

Very elderly patients were less likely to continue antihypertensive therapy over the first year compared with their younger counterparts. Our findings suggest that a low comorbidity index and lack of medical aid support negatively affect the treatment persistence in this population.

A medication adherence and persistence comparison of hypertensive patients treated with single-, double- and triple-pill combination therapy

OBJECTIVE

Fixed-dose combination therapy reduces pill burden and may, therefore, improve medication adherence and health outcomes. This study compared adherence to and persistence with single-, double-, and triple-pill treatment regimens among hypertensive patients in a US clinical practice setting.

METHODS

Adults with hypertension treated with three anti-hypertensive medications were identified. Index date was the first occurrence of a single-, double-, or triple-pill regimen with olmesartan or valsartan plus amlodipine and hydrochlorothiazide from July 2010 to September 2011. Patients were followed for 12 months to assess adherence (proportion of days covered [PDC] ≥ 80%) and time to discontinuation (medication gap ≥ 60 days) of the index regimen. Multivariate regression models were used to compare adjusted outcomes.

RESULTS

The number of prescribed pills in the index regimen was monotonically related to adherence with 55.3%, 40.4% and 32.6% of patients having PDC ≥ 80% in the single-, double- and triple-pill cohorts, respectively. In adjusted analysis, patients in the double- (odds ratio [OR]: 0.45; 95% confidence interval [CI]: 0.42-0.48) and triple-pill (OR: 0.26; 95% CI: 0.22-0.30) cohorts were less likely to be adherent to their index regimens than those in the single-pill cohort. Double-pill (hazard ratio [HR]: 1.89; 95% CI: 1.74-2.06) and triple-pill patients (HR: 2.49; 95% CI: 2.14-2.88) were more likely to discontinue treatment than single-pill patients.

CONCLUSIONS

Greater pill burden was directly and significantly associated with decreased adherence and persistence with antihypertensive therapies in real-practice settings. Use of fixed-dose combinations that reduce pill burden could help patients to continue treatment and may result in improved clinical outcomes. Typical of observational studies, the potential for residual confounding of adherence estimates remains due to lack of randomization of treatment groups.

Unintentional non-adherence to chronic prescription medications: how unintentional is it really?

Background

Unintentional non-adherence has been characterized as passively inconsistent medication-taking behavior (forgetfulness or carelessness). Our objectives were to: (1) study the prevalence and predictors of unintentional non-adherence; and (2) explore the interrelationship between intentional and unintentional non-adherence in relation to patients’ medication beliefs.

Methods

We conducted a cross-sectional survey of adults with asthma, hypertension, diabetes, hyperlipidemia, osteoporosis, or depression from the Harris Interactive Chronic Illness Panel. The analytic sample for this study included 24,017 adults who self-identified themselves as persistent to prescription medications for their index disease. They answered three questions on unintentional non-adherence (forgot, ran out, being careless), 11 questions on intentional non-adherence, and three multi-item scales assessing perceived need for medication (k = 10), perceived medication concerns (k = 6), and perceived medication affordability (k = 4). Logistic regression was used to model predictors of each unintentional non-adherence behavior. Baron and Kenny’s regression approach was used to test the mediational effect of unintentional non-adherence on the relationship between medication beliefs and intentional non-adherence. Bootstrapping was employed to confirm the statistical significance of these results.

Results

For the index disease, 62% forgot to take a medication, 37% had run out of the medication, and 23% were careless about taking the medication. Common multivariate predictors (p < .001) of the three behaviors were: (1) lower perceived need for medications; (2) more medication affordability problems; (3) worse self-rated health; (4) diabetes or osteoporosis (relative to hypertension); and (5) younger age. Unique statistically-significant predictors of the three behaviors were: (a) ‘forgot to take medications’ - greater concerns about the index medication and male gender; (b) ‘run out of medications’ - non-white race, asthma, and higher number of total prescription medications; (c) ‘being careless’ - greater medication concerns. Mediational tests confirmed the hypothesis that the effect of medication beliefs (perceived need, concerns, and affordability) on intentional non-adherence is mediated through unintentional non-adherence.

Conclusions

For our study sample, unintentional non-adherence does not appear to be random and is predicted by medication beliefs, chronic disease, and sociodemographics. The data suggests that the importance of unintentional non-adherence may lie in its potential prognostic significance for future intentional non-adherence. Health care providers may consider routinely inquiring about unintentional non-adherence in order to proactively address patients’ suboptimal medication beliefs before they choose to discontinue therapy all together.

Unintentional non-adherence to chronic prescription medications: how unintentional is it really?

BACKGROUND

Unintentional non-adherence has been characterized as passively inconsistent medication-taking behavior (forgetfulness or carelessness). Our objectives were to: (1) study the prevalence and predictors of unintentional non-adherence; and (2) explore the interrelationship between intentional and unintentional non-adherence in relation to patients' medication beliefs.

METHODS

We conducted a cross-sectional survey of adults with asthma, hypertension, diabetes, hyperlipidemia, osteoporosis, or depression from the Harris Interactive Chronic Illness Panel. The analytic sample for this study included 24,017 adults who self-identified themselves as persistent to prescription medications for their index disease. They answered three questions on unintentional non-adherence (forgot, ran out, being careless), 11 questions on intentional non-adherence, and three multi-item scales assessing perceived need for medication (k = 10), perceived medication concerns (k = 6), and perceived medication affordability (k = 4). Logistic regression was used to model predictors of each unintentional non-adherence behavior. Baron and Kenny's regression approach was used to test the mediational effect of unintentional non-adherence on the relationship between medication beliefs and intentional non-adherence. Bootstrapping was employed to confirm the statistical significance of these results.

RESULTS

For the index disease, 62% forgot to take a medication, 37% had run out of the medication, and 23% were careless about taking the medication. Common multivariate predictors (p < .001) of the three behaviors were: (1) lower perceived need for medications; (2) more medication affordability problems; (3) worse self-rated health; (4) diabetes or osteoporosis (relative to hypertension); and (5) younger age. Unique statistically-significant predictors of the three behaviors were: (a) 'forgot to take medications' - greater concerns about the index medication and male gender; (b) 'run out of medications' - non-white race, asthma, and higher number of total prescription medications; (c) 'being careless' - greater medication concerns. Mediational tests confirmed the hypothesis that the effect of medication beliefs (perceived need, concerns, and affordability) on intentional non-adherence is mediated through unintentional non-adherence.

CONCLUSIONS

For our study sample, unintentional non-adherence does not appear to be random and is predicted by medication beliefs, chronic disease, and sociodemographics. The data suggests that the importance of unintentional non-adherence may lie in its potential prognostic significance for future intentional non-adherence. Health care providers may consider routinely inquiring about unintentional non-adherence in order to proactively address patients' suboptimal medication beliefs before they choose to discontinue therapy all together.

Comparing Medication Adherence Methods in Lipid-Modifying Therapy

Background:

Investigators have employed a number of different methods to calculate adherence estimates for patients taking lipid-modifying therapy (LMT), including measures with different numerator and denominator options. Although at least one method is known to correlate well with cardiovascular outcomes, most have not been evaluated in outcomes studies.

Objectives:

To evaluate different methods for measuring adherence, using LMT as a case example, and to determine whether estimates for adherence differ statistically and/or whether different methods can lead to different conclusions about patient adherence.

Methods:

Adherence ratios were calculated using 8 different methods for 12,448 patients who were in a managed-care system and were considered new starts with statin therapy. The calculated measures were compared and tested for differences. Patients were categorized as adherent by each method, using a threshold of 0.8, and the proportions of patients categorized as adherent were compared for differences between adherence calculation methods.

Results:

Adherence ratios calculated with like observation intervals did not vary substantially, regardless of which method for measuring medication availability was used. Those calculated with different observation intervals had substantial variability. Mean adherence ratios ranged between 0.777 and 0.798 for difference in days' observation intervals; they ranged between 0.618 and 0.630 for the predefined interval. Differences between ratios calculated using these different denominators were statistically significant (p < 0.008). Correlations between ratios were statistically significant for all comparisons (p < 0.001). Correlation coefficients ( r) were 0.64 for comparisons between ratios with different denominators versus 1.0 for comparisons with like denominators. Categorization as adherent or nonadherent differed between the methods for about 20% of patients.

Conclusions:

Significant differences were found to be based on observation period but not on medication availability. Studies of adherence should be interpreted with caution depending on which method is used, and particular interest should be paid to whether the choice of methods is consistent with study objectives and to the observation interval, as different methods may lead to different conclusions about patient adherence. Further research in LMT and other therapeutic areas is needed to determine which methods correlate best with positive patient outcomes, such as reductions in low-density lipoprotein cholesterol and cardiovascular events.

Structural equation modeling of the proximal-distal continuum of adherence drivers

OBJECTIVES

Nonadherence to prescription medications has been shown to be significantly influenced by three key medication-specific beliefs: patients' perceived need for the prescribed medication, their concerns about the prescribed medication, and perceived medication affordability. Structural equation modeling was used to test the predictors of these three proximal determinants of medication adherence using the proximal-distal continuum of adherence drivers as the organizing conceptual framework.

METHODS

In Spring 2008, survey participants were selected from the Harris Interactive Chronic Illness Panel, an internet-based panel of hundreds of thousands of adults with chronic disease. Respondents were eligible for the survey if they were aged 40 years and older, resided in the US, and reported having at least one of six chronic diseases: asthma, diabetes, hyperlipidemia, hypertension, osteoporosis, or other cardiovascular disease. A final sample size of 1072 was achieved. The proximal medication beliefs were measured by three multi-item scales: perceived need for medications, perceived medication concerns, and perceived medication affordability. The intermediate sociomedical beliefs and skills included four multi-item scales: perceived disease severity, knowledge about the prescribed medication, perceived immunity to side effects, and perceived value of nutraceuticals. Generic health beliefs and skills consisted of patient engagement in their care, health information-seeking tendencies, internal health locus of control, a single-item measure of self-rated health, and general mental health. Structural equation modeling was used to model proximal-distal continuum of adherence drivers.

RESULTS

The average age was 58 years (range = 40-90 years), and 65% were female and 89% were white. Forty-one percent had at least a four-year college education, and just under half (45%) had an annual income of $50,000 or more. Hypertension and hyperlipidemia were each reported by about a quarter of respondents (24% and 23%, respectively). A smaller percentage of respondents had osteoporosis (17%), diabetes (15%), asthma (13%), or other cardiovascular disease (8%). Three independent variables were significantly associated with the three proximal adherence drivers: perceived disease severity, knowledge about the medication, and perceived value of nutraceuticals. Both perceived immunity to side effects and patient engagement was significantly associated with perceived need for medications and perceived medication concerns.

CONCLUSION

Testing the proximal-distal continuum of adherence drivers shed light on specific areas where adherence dialogue and enhancement should focus. Our results can help to inform the design of future adherence interventions as well as the content of patient education materials and adherence reminder letters. For long-term medication adherence, patients need to autonomously and intrinsically commit to therapy and that, in turn, is more likely to occur if they are both informed (disease and medication knowledge and rationale, disease severity, consequences of nonadherence, and side effects) and motivated (engaged in their care, perceive a need for medication, and believe the benefits outweigh the risks).

Combining antihypertensive and antihyperlipidemic agents - optimizing cardiovascular risk factor management

Clinical guidelines now recognize the importance of a multifactorial approach to managing cardiovascular (CV) risk. This idea was taken a step further with the concept of the Polypill™. There are, however, considerable patent, pharmacokinetic, pharmacodynamic, registration, and cost implications that will need to be overcome before the Polypill™ or other single-pill combinations of CV medications become widely available. However, a medication targeting blood pressure (BP) and lipids provides much of the proposed benefits of the Polypill™. A single-pill combination of the antihypertensive amlodipine besylate and the lipid-lowering medication atorvastatin calcium (SPAA) is currently available in many parts of the world. This review describes the rationale for this combination therapy and the clinical trials that have demonstrated that these two agents can be combined without the loss of efficacy for either agent or an increase in the incidence of adverse events. The recently completed Cluster Randomized Usual Care vs Caduet Investigation Assessing Long-term-risk (CRUCIAL trial) is discussed in detail. CRUCIAL was a 12-month, international, multicenter, prospective, open-label, parallel design, cluster-randomized trial, which demonstrated that a proactive intervention strategy based on SPAA in addition to usual care (UC) had substantial benefits on estimated CV risk, BP, and lipids over continued UC alone. Adherence with antihypertensive and lipid-lowering therapies outside of the controlled environment of clinical trials is very low (~30%–40% at 12 months). Observational studies have demonstrated that improving adherence to lipid-lowering and antihypertensive medications may reduce CV events. One means of improving adherence is the use of single-pill combinations. Real-world observational studies have demonstrated that patients are more adherent to SPAA than co-administered antihypertensive and lipid-lowering therapy, and this improved adherence translated to reduced CV events. Taken together, these findings suggest that SPAA can play an important role in helping physicians improve the management of CV risk in their patients.

Adherence to lipid-lowering agents among 11,042 patients in clinical practice

AIMS

Dyslipidaemia is a poorly-controlled condition in clinical practice largely because of poor adherence to medication regimens by patients. This study evaluated the levels of and factors associated with adherence to lipid-lowering agents in a large Chinese population.

METHODS

From a validated clinical database, we included all patients who attended any public, primary care clinics in one large Territory of Hong Kong for medication refill at least twice during the study period January 2004 to June 2007. The major outcome variable was Medication Possession Ratio (MPR), an internationally-recognised metric to measure drug adherence. The factors associated with optimal drug adherence (MPR ≥ 0.8) were evaluated by multivariate regression analysis.

RESULTS

From 11,042 eligible patients, 90% were adherent. After adjusting for patients' age, gender, socioeconomic status, service type, district of residence, visit type (new visits vs. follow-up visits), the number of comorbidities and the drug class (statin vs. fibrates), older patients [aged 50-59 years; adjusted odds ratio (AOR) 1.30, p = 0.009; 60-69 years; AOR 1.53, p < 0.001; ≥ 70 years; AOR 1.72, p < 0.001], attendance in family medicine specialist clinics (FMSC; AOR 1.56, p < 0.001), follow-up visits (AOR 2.93, p < 0.001) and the presence of comorbidities (one comorbidity; AOR 1.45, p < 0.001; ≥ 2 comorbidities; AOR 1.56, p < 0.001) were associated with optimal drug adherence.

DISCUSSION AND CONCLUSION

These findings carry an implication that younger subjects, new patients, visitors in clinics other than FMSC and those without comorbidities should receive more meticulous monitoring of their medication-taking behaviour. Future studies should evaluate the major reasons for non-adherence among them.

Does a single-pill antihypertensive/lipid-lowering regimen improve adherence in US managed care enrolees? A non-randomized, observational, retrospective study

BACKGROUND

A previous study in 4703 patients suggested that a single-pill combination of amlodipine and atorvastatin is associated with greater adherence to therapy than a two-pill calcium channel antagonist (calcium channel blocker [CCB]) and HMG-CoA reductase inhibitor (statin) regimen. However, the impact of prior medication use on the potential adherence benefits of single-pill amlodipine/atorvastatin has not been studied.

OBJECTIVE

To compare adherence to single-pill amlodipine/atorvastatin versus two-pill CCB + statin regimens in a large managed care population, stratified according to prior CCB and statin use.

METHODS

This retrospective study was conducted among managed care enrolees in the US. Patients included in the analysis had to have a pharmacy claim for single-pill amlodipine/atorvastatin or claims for both a CCB and a statin within any 30-day window between April 2004 and April 2005. Adherence was measured over 6 months following the index date (the date of the first single-pill amlodipine/atorvastatin claim or of the claim for the second medication class for any two-pill CCB + statin regimen) as the proportion of days covered (PDC) by both CCB and statin therapy; patients were considered 'adherent' if PDC was > or =80%. Patients were divided into four cohorts based on pre-index CCB and statin use: (i) naive (CCB)/naive (statin); (ii) experienced (CCB)/naive (statin); (iii) naive (CCB)/experienced (statin); and (iv) experienced (CCB)/experienced (statin). Within each cohort, adherence was compared for patients receiving single-pill amlodipine/atorvastatin versus two-pill amlodipine + atorvastatin or other two-pill CCB + statin regimens (including amlodipine or atorvastatin but not both) at index. Multivariable logistic regression with propensity score weighting was used to adjust for covariates, including age, sex and co-morbidities.

RESULTS

In total, 35,430 patients were included in the analysis. At month 6 (after adjusting for covariates), patients in the experienced (CCB)/naive (statin) cohort receiving single-pill amlodipine/atorvastatin were more than twice as likely to be adherent as those receiving two-pill amlodipine + atorvastatin (odds ratio [OR] 2.20; p < 0.0001) or other two-pill CCB + statin regimens (OR 2.75; p < 0.0001). Similarly, patients in the naive (CCB)/experienced (statin) cohort receiving single-pill amlodipine/atorvastatin were more likely to be adherent than those receiving two-pill amlodipine + atorvastatin (OR 1.72; p < 0.0001) or other two-pill CCB + statin regimens (OR 2.81; p < 0.0001). In contrast, in the naive (CCB)/naive (statin) cohort there was no significant difference in adherence between patients receiving single-pill amlodipine/atorvastatin versus two-pill amlodipine + atorvastatin (OR 1.00), although patients receiving single-pill amlodipine/atorvastatin were slightly more likely to be adherent than those receiving other two-pill CCB + statin regimens (OR 1.29; p < 0.01). In the experienced (CCB)/experienced (statin) cohort there was also no significant difference between patients receiving single-pill amlodipine/atorvastatin versus two-pill amlodipine + atorvastatin (OR 1.08), and only a slightly greater likelihood of achieving adherence to single-pill amlodipine/atorvastatin versus other two-pill CCB + statin regimens (OR 1.19; p < 0.01).

CONCLUSIONS

This large retrospective study confirms previous observations that single-pill amlodipine/atorvastatin can help improve adherence versus two-pill CCB + statin regimens. However, greater improvements in adherence are likely to be observed in patients with prior experience of either CCB or statin therapy than in those either naive to, or experienced with, both therapies.

Amlodipine/Atorvastatin: a review of its use in the treatment of hypertension and dyslipidaemia and the prevention of cardiovascular disease

Amlodipine/atorvastatin (Caduet) is a single-tablet, fixed-dose combination of the dihydropyridine calcium channel antagonist amlodipine and the HMG-CoA reductase inhibitor atorvastatin. The bioavailability of amlodipine and atorvastatin with a single-tablet, fixed-dose amlodipine/atorvastatin combination was not significantly different to that with coadministered separate amlodipine and atorvastatin tablets. In well controlled clinical trials in patients with hypertension and dyslipidaemia, once-daily amlodipine and atorvastatin (administered as the single-tablet, fixed-dose combination or coadministered as two separate tablets) effectively reduced systolic BP (SBP) and low-density lipoprotein cholesterol (LDL-C) levels, and enabled more patients to achieve BP and LDL-C goals than single-agent or placebo therapy. There was no modification of the effect of amlodipine on SBP when administered in combination with atorvastatin and there was no modification of the effect of atorvastatin on LDL-C when administered in combination with amlodipine. In noncomparative, titration-to-goal, open-label 'real-world' trials, the single-tablet, fixed-dose combination of amlodipine/atorvastatin enabled patients with hypertension and dyslipidaemia to achieve both BP and LDL-C goals. Administration of a single tablet of amlodipine/atorvastatin, compared with coadministration of these agents as two separate tablets, improved patient adherence, according to a retrospective study that utilized prescription refill rates from a large US insurance database. Data from the large, randomized, double-blind, placebo-controlled ASCOT-LLA trial also demonstrated that the combination of amlodipine-based therapy and atorvastatin was effective in preventing cardiovascular (CV) endpoints in hypertensive patients at risk of CV disease (CVD). In summary, amlodipine/atorvastatin offers a convenient and effective approach to improving adherence and managing CV risk in hypertensive patients with dyslipidaemia or at risk of CVD.

The cost and effectiveness of adherence-improving interventions for antihypertensive and lipid-lowering drugs*

AIMS

Adherence to cardiovascular medications is poor. Accordingly, interventions have been proposed to improve adherence. However, as intervention-associated costs are rarely considered in full, we sought to review the effectiveness and costs associated with different adherence-improving interventions for cardiovascular disease therapies.

METHODS

We reviewed MEDLINE to update a prior review of interventions to improve adherence with antihypertensive and/or lipid-lowering therapy covering January 1972 to June 2002, to add studies published from July 2002 to October 2007. Eligible studies evaluated > or = 1 intervention compared with a control, used measures other than self-report, reported significant improvement in adherence and followed patients for > or = 6 months. Effectiveness was measured as relative improvement (RI), the ratio of adherence in the intervention group to the control group. Costs were calculated based on those reported in the analysis, if available or estimated based on resource use described. All costs were truncated to 6 months and adjusted to 2007 US$.

RESULTS

Of 755 new articles, five met all eligibility criteria. Combining with the prior review gave 23 interventions from 18 studies. RI in adherence ranged from 1.11 to 4.65. Six-month intervention costs ranged from $10 to $142 per patient. Reminders had the lowest effectiveness (RI: 1.11-1.14), but were least costly ($10/6 months). Case management was most effective (RI: 1.23-4.65), but the most costly ($90-$130/6 months).

CONCLUSIONS

Generally, we found a positive association between intervention costs and effectiveness. Therefore, consideration of intervention costs, along with the benefits afforded to adherence, may help guide the design and implementation of adherence-improving programs.

Can adherence to antihypertensive therapy be used to promote adherence to statin therapy?

OBJECTIVE

To compare adherence with statin therapy in patients switching to single-pill amlodipine besylate/atorvastatin calcium with patients adding a separate statin to their amlodipine regimen.

METHODS

We identified hypertensive patients prescribed amlodipine who switched to amlodipine/atorvastatin (switch) or added a statin to their amlodipine regimen (add-on) from July 2004 to June 2007. Propensity score matching (1 switch:3 add-on) was applied based on 'nearest neighbor' approach. The primary adherence measure was patients with proportion of days covered (PDC) >/=0.80 at 180 days; secondary measures included mean PDC and persistence. A sensitivity analysis was performed, accounting for total statin/amlodipine exposure.

RESULTS

Among 4556 matched patients (n = 1139 switch; n = 3417 add-on), mean age was 53.9 years and 52.1% were male. After 180 days, adherence with statin therapy was higher for the switch vs add-on cohort (50.8% vs 44.3%; P < 0.001). After adjusting for pre-index amlodipine adherence, the switch cohort was more likely to be adherent than the add-on cohort (odds ratio: 1.64 [95% confidence interval: 1.42 to 1.89]). Persistence was higher in the switch than the add-on cohort (127.6 vs 117 days; P < 0.001).

CONCLUSION

Hypertensive patients taking amlodipine who initiated statin therapy via single-pill amlodipine/atorvastatin were more likely to remain adherent to their statin than patients adding a separate statin to their antihypertensive regimen.