Compliance and antihypertensive efficacy of amlodipine compared with nifedipine slow-release

Sensitivity of estimands in clinical trials with imperfect compliance

In clinical trials that are subject to noncompliance, the commonly used intention-to-treat estimand is valid as a causal effect of treatment assignment but is sensitive to the level of compliance. An alternative estimand, the complier average causal effect (CACE), measures the average effect of treatment received in the latent subset of subjects who would comply with either assigned treatment. Because the principal stratum of compliers can vary with the circumstances of the trial, CACE too depends on the compliance fraction. We propose a model in which an underlying latent proto-compliance interacts with trial characteristics to determine a subject's compliance behavior. When the latent compliance is independent of the individual treatment effect, the average causal effect is constant across compliance classes, and CACE is robust across trials and equal to the population average causal effect. We demonstrate the potential degree of sensitivity of CACE in a simulation study, an analysis of data from a trial of vitamin A supplementation in children, and a meta-analysis of trials of epidural analgesia in labor.

Improving medication adherence in hypertensive patients: A scoping review

In recent years, interest in medication adherence has greatly increased. Adherence has been particularly well studied in the context of arterial hypertension treatment. Numerous interventions have addressed this issue, however, the effort to improve adherence has been often frustrating and frequently disorganized. The aim of present study was to perform a scoping review of medication adherence interventions in hypertensive patients, so that a clear overview was achieved. Moreover, an evidence-based categorization of interventions was developed. The review was performed according to the PRISMA-ScR statement. MEDLINE and Web of Science were searched, and studies published from database inception until August 17, 2020 were included. A total of 2994 non-duplicate studies were retrieved. After screening and eligibility phases, a total of 45 articles were included. Studies were analyzed regarding their design, participant characteristics and management of adherence strategies employed. Furthermore, medication adherence and blood pressure outcomes, as well as adherence measuring tools were evaluated. Each study's intervention was then categorized using a novel evidence-based system of categorization, derived from the conceptual clustering framework used in machine learning. This work is an important step in pushing for better informed and more efficient future research efforts, both by providing an overview of the research field and by creating a new, evidence-based intervention categorization tool. It also provides valuable information to clinicians about medication adherence to antihypertensive therapy.

Safety of Antihypertensive Medications in Pregnancy: Living With Uncertainty

See Article by Mito et al.

Identification and assessment of adherence-enhancing interventions in studies assessing medication adherence through electronically compiled drug dosing histories: a systematic literature review and meta-analysis

Background

Non-adherence to medications is prevalent across all medical conditions that include ambulatory pharmacotherapy and is thus a major barrier to achieving the benefits of otherwise effective medicines.

Objective

The objective of this systematic review was to identify and to compare the efficacy of strategies and components thereof that improve implementation of the prescribed drug dosing regimen and maintain long-term persistence, based on quantitative evaluation of effect sizes across the aggregated trials.

Data sources

MEDLINE, EMBASE, CINAHL, the Cochrane Library, and PsycINFO were systematically searched for randomized controlled trials that tested the efficacy of adherence-enhancing strategies with self-administered medications. The searches were limited to papers in the English language and were included from database inception to 31 December 2011.

Study selection

Our review included randomized controlled trials in which adherence was assessed by electronically compiled drug dosing histories. Five thousand four hundred studies were screened. Eligibility assessment was performed independently by two reviewers. A structured data collection sheet was developed to extract data from each study.

Study appraisal and synthesis methods

The adherence-enhancing components were classified in eight categories. Quality of the papers was assessed using the criteria of the Cochrane Handbook for Systematic Reviews of Interventions guidelines to assess potential bias. A combined adherence outcome was derived from the different adherence variables available in the studies by extracting from each paper the available adherence summary variables in a pre-defined order (correct dosing, taking adherence, timing adherence, percentage of adherent patients). To study the association between the adherence-enhancing components and their effect on adherence, a linear meta-regression model, based on mean adherence point estimates, and a meta-analysis were conducted.

Results

Seventy-nine clinical trials published between 1995 and December 2011 were included in the review. Patients randomized to an intervention group had an average combined adherence outcome of 74.3 %, which was 14.1 % higher than in patients randomized to the control group (60.2 %). The linear meta-regression analysis with stepwise variable selection estimated an 8.8 % increase in adherence when the intervention included feedback to the patients of their recent dosing history (EM-feedback) (p < 0.01) and a 5.0 % increase in adherence when the intervention included a cognitive-educational component (p = 0.02). In addition, the effect of interventions on adherence decreased by 1.1 % each month. Sensitivity analysis by selecting only high-quality papers confirmed the robustness of the model. The random effects model in the meta-analysis, conducted on 48 studies, confirmed the above findings and showed that the improvement in adherence was 19.8 % (95 % CI 10.7–28.9 %) among patients receiving EM-feedback, almost double the improvement in adherence for studies that did not include this type of feedback [10.3 % (95 % CI 7.5–13.1 %)] (p < 0.01). The improvement in adherence was 16.1 % (95 % CI 10.7–21.6 %) in studies that tested cognitive-educational components versus 10.1 % (95 % CI 6.6–13.6 %) in studies that did not include this type of intervention (p = 0.04). Among 57 studies measuring clinical outcomes, only 8 reported a significant improvement in clinical outcome.

Limitations

Despite a common measurement, the meta-analysis was limited by the heterogeneity of the pooled data and the different measures of medication adherence. The funnel plot showed a possible publication bias in studies with high variability of the intervention effect.

Conclusions

Notwithstanding the statistical heterogeneity among the studies identified, and potential publication bias, the evidence from our meta-analysis suggests that EM-feedback and cognitive-educational interventions are potentially effective approaches to enhance patient adherence to medications. The limitations of this research highlight the urgent need to define guidelines and study characteristics for research protocols that can guide researchers in designing studies to assess the effects of adherence-enhancing interventions.

Electronic supplementary material

The online version of this article (doi:10.1007/s40265-013-0041-3) contains supplementary material, which is available to authorized users.

Efficacy and safety of two ramipril and hydrochlorothiazide fixed-dose combination formulations in adults with stage 1 or stage 2 arterial hypertension evaluated by using ABPM

BACKGROUND

Fixed-dose combinations of antihypertensive agents demonstrate advantages in terms of efficacy, tolerability, and treatment adherence.

OBJECTIVE

This study was designed to compare the efficacy and safety of 2 ramipril and hydrochlorothiazide (HCTZ) fixed-dose combinations in patients with hypertension stage 1 or 2. Patients' blood pressure (BP) profiles were evaluated by using 24-hour ambulatory BP monitoring (ABPM).

METHODS

This was a multicenter, prospective, randomized, open-label, parallel-group, noninferiority trial of adult patients (age ≥18 years) with hypertension stage 1 or 2 and systolic blood pressure (SBP) within 140 to 179 mm Hg or diastolic blood pressure (DBP) 90 to 109 mm Hg. After a 2-week washout period, eligible patients were randomized to receive 1 of 2 ramipril/HCTZ fixed-dose combination formulations (5/25 mg/d) for 8 weeks. The primary end point was the difference in 24-hour ABPM SBP/DBP mean reductions between groups after 8 weeks of treatment. The secondary end points were the changes in daytime and nighttime ABPM and in office BP. Safety profile and tolerability assessments included monitoring of adverse events.

RESULTS

A total of 102 patients with hypertension (54 in group A [test formulation] and 48 in group B [reference formulation]), aged 27 to 85 years, completed the 8-week treatment period. The decreases in SBP and DBP according to 24-hour ABPM from baseline to week 8 were significant and similar in both groups. SBP decreased from 149.1 to 133.0 mm Hg (-16.1 mm Hg) in group A and from 146.2 to 130.6 mm Hg in group B (-15.6 mm Hg) (P = 0.8537); DBP was reduced by 8.8 mm Hg in group A and by 8.5 mm Hg in group B (P = 0.8748). Because the lower 95% CI limit for the difference between groups A and B of 3.96 mm Hg in SBP and 3.54 mm Hg in DBP was lower than that preestablished by the trial protocol (4 mm Hg), noninferiority of the test formulation was demonstrated compared with the reference formulation. For the secondary end points, there was no significant difference between groups in SBP and DBP during daytime or nighttime at the end of week 8. Office BP was significantly reduced in both treatment groups, with no significant differences between groups. The incidence of adverse events was 23.7% in group A and 21.7% in group B.

CONCLUSIONS

Both treatment options were well tolerated and equally reduced BP. The results support the conclusion that group A (new fixed-dose combination of ramipril/HCTZ) was noninferior to group B (reference medication in Brazil). ISRCTN Register: ISRCTN05051235.

Low-dose dextromethorphan, a NADPH oxidase inhibitor, reduces blood pressure and enhances vascular protection in experimental hypertension

Background

Vascular oxidative stress may be increased with age and aggravate endothelial dysfunction and vascular injury in hypertension. This study aimed to investigate the effects of dextromethorphan (DM), a NADPH oxidase inhibitor, either alone or in combination treatment, on blood pressure (BP) and vascular protection in aged spontaneous hypertensive rats (SHRs).

Methodology/Principal Findings

Eighteen-week-old WKY rats and SHRs were housed for 2 weeks. SHRs were randomly assigned to one of the 12 groups: untreated; DM monotherapy with 1, 5 or 25 mg/kg/day; amlodipine (AM, a calcium channel blocker) monotherapy with 1 or 5 mg/kg/day; and combination therapy of DM 1, 5 or 25 mg/kg/day with AM 1 or 5 mg/kg/day individually for 4 weeks. The in vitro effects of DM were also examined. In SHRs, AM monotherapy dose-dependently reduced arterial systolic BP. DM in various doses significantly and similarly reduced arterial systolic BP. Combination of DM with AM gave additive effects on BP reduction. DM, either alone or in combination with AM, improved aortic endothelial function indicated by ex vivo acetylcholine-induced relaxation. The combination of low-dose DM with AM gave most significant inhibition on aortic wall thickness in SHRs. Plasma total antioxidant status was significantly increased by all the therapies except for the combination of high-dose DM with high-dose AM. Serum nitrite and nitrate level was significantly reduced by AM but not by DM or the combination of DM with AM. Furthermore, in vitro treatment with DM reduced angiotensin II-induced reactive oxygen species and NADPH oxidase activation in human aortic endothelial cells.

Conclusions/Significance

Treatment of DM reduced BP and enhanced vascular protection probably by inhibiting vascular NADPH oxidase in aged hypertensive animals with or without AM treatment. It provides the potential rationale to a novel combination treatment with low-dose DM and AM in clinical hypertension.

Benefits of once-daily therapies in the treatment of hypertension

In patients with hypertension, 24-hour blood pressure control is the major therapeutic goal. The number of daily doses is one characteristic of an antihypertensive agent that may affect the adequacy of 24-hour control. One measure of therapeutic coverage is the 24-hour trough-to-peak ratio, which determines the suitability of an agent for once-daily administration. The closer an agent is to a 100% trough-to-peak ratio, the more uniform the 24-hour coverage and therefore blood pressure control. High trough-to-peak ratio, long-acting antihypertensive medications lower blood pressure more gradually, which reduces the likelihood of adverse events attributable to abrupt drug action that occurs with shorter-acting agents. In hypertension, the natural diurnal variation of blood pressure may be altered, including elevated nighttime pressures. An optimal once-daily hypertension therapy would not only lower blood pressure but also normalize any blunted circadian variations in blood pressure. The benefits of once-daily agents with sustained therapeutic coverage may also be explained, in part, by increased patient adherence to simpler regimens as well as lower loss of blood pressure control during virtually inevitable intermittent noncompliance. Studies have demonstrated that once-daily antihypertensive agents have the highest adherence compared with twice-daily or multiple daily doses, including greater adherence to the prescribed timing of doses.

Demonstration of safety in Alzheimer's patients for intervention with an anti-hypertensive drug Nilvadipine: results from a 6-week open label study

BACKGROUND

Nilvadipine may lower rates of conversion from mild-cognitive impairment to Alzheimer's disease (AD), in hypertensive patients. However, it remains to be determined whether treatment with nilvadipine is safe in AD patients, given the higher incidence of orthostatic hypotension (OH) in this population, who may be more likely to suffer from symptoms associated with the further exaggeration of a drop in BP.

OBJECTIVE

The aim of this study was to investigate the safety and tolerability of nilvadipine in AD patients.

METHODS

AD patients in the intervention group (n = 56) received nilvadipine 8  mg daily over 6-weeks, compared to the control group (n = 30) who received no intervention. Differences in systolic (SBP) and diastolic (DBP) blood pressure, before and after intervention, was assessed using automated sphygmomanometer readings and ambulatory BP monitors (ABP), and change in OH using a finometer. Reporting of adverse events was monitored throughout the study.

RESULTS

There was a significant reduction in the SBP of treated patients compared to non-treated patients but no significant change in DBP. Individuals with higher initial blood pressure (BP) had greater reduction in BP but individuals with normal BP did not experience much change in their BP. While OH was present in 84% of the patients, there was no further drop in BP recorded on active stand studies. There were no significant differences in adverse event reporting between groups.

CONCLUSION

Nilvadipine was well tolerated by patients with AD. This study supports further investigation of its efficacy as a potential treatment for AD.

Intentional and unintentional medication non-adherence: a comprehensive framework for clinical research and practice? A discussion paper

Non-adherence to medications is a prevalent and persistent healthcare problem, particularly for patients with a chronic disorder. Researchers have endeavoured to address poor adherence for the past five decades resulting in the accumulation of a vast body of literature. Despite the enormity of research conducted, interventions to date have neither been cost-effective nor predictably clinically effective in enhancing medication adherence. Though concerning, such contemporary information serves to refocus attention on the adequacy of knowledge regarding the factors influencing medication non-adherence. Although little consensus exists regarding the optimal categorisation of these influencing factors, increasingly, the broad and 'all encompassing' categorisation of intentional and unintentional factors is being used to account for patient medication-taking behaviours and actions. An extensive review of the related literature provides the basis for a critical discussion on the value and comprehensiveness of this current classification in guiding future adherence research and consequent clinical interventions. An appraisal of this categorisation is important if decisions regarding interventions are not to be made in a vacuum of insufficient understanding, which would result in the continued ineffective use and distribution of valuable resources to combat non-adherence.

Impact of compliance with oral antihyperglycemic agents on health outcomes in type 2 diabetes mellitus: a focus on frequency of administration

Compliance with treatment is crucial to the optimal management of any chronic disease. Non-compliance with antihyperglycemic treatment is clearly a significant issue for patients with type 2 diabetes mellitus as it decreases the efficacy of the treatment and increases the risk of developing microvascular and macrovascular complications, therefore increasing the human and economic costs of this disease. The effect of low compliance on metabolic control has been shown to represent an increase of up to 1.4% in glycosylated hemoglobin. Achieving optimal compliance is therefore a therapeutic objective of prime importance. Many factors have been cited as contributing to poor compliance. Some of these, such as age, severe complications and disabilities, and social, educational, and financial difficulties, affect compliance with treatment in quite a significant manner, but are not modifiable by the healthcare provider. Other factors, such as the number of tablets per dose and polymedication, are modifiable but do not appear to be of major importance, whereas the frequency of administration is both an important and a modifiable factor affecting compliance with treatment. One strategy for optimization of compliance involves treatment of type 2 diabetes using oral antihyperglycemic agents with once-daily formulations. Recent data indicate that reducing the daily administration frequency of oral antihyperglycemic agents improves compliance with treatment and consequently metabolic control. Therefore, optimization of treatment through a reduction in the frequency of antihyperglycemic administration could be a valuable weapon in the battle to improve health outcomes and reduce the burden of type 2 diabetes.

Medication adherence and persistence: a comprehensive review

Estimates of adherence to long-term medication regimens range from 17% to 80%, and nonadherence (or nonpersistence) can lead to increased morbidity, mortality, and healthcare costs. Multifaceted interventions that target specific barriers to adherence are most effective, because they address the problems and reinforce positive behaviors. Providers must assess their patients' understanding of the illness and its treatment, communicate the benefits of the treatment, assess their patients' readiness to carry out the treatment plan, and discuss any barriers or obstacles to adherence that patients may have. A positive, supporting, and trusting relationship between patient and provider improves adherence. Individual patient factors also affect adherence. For example, conditions that impair cognition have a negative impact on adherence. Other factors--such as the lack of a support network, limited English proficiency, inability to obtain and pay for medications, or severe adverse effects or the fear of such effects--are all barriers to adherence. There are multiple reasons for nonadherence or nonpersistence; the solution needs to be tailored to the individual patient's needs. To have an impact on adherence, healthcare providers must understand the barriers to adherence and the methods or tools needed to overcome them. This report describes the barriers to medication adherence and persistence and interventions that have been used to address them; it also identifies interventions and compliance aids that practitioners and organizations can implement.

Pharmacokinetics of Once-Daily Saquinavir/Ritonavir in HIV-Infected Subjects: Comparison with the Standard Twice-Daily Regimen

Objective

To evaluate the steady-state pharmacokinetics and safety of two once-daily saquinavir/ritonavir (SQV/RTV) regimens, 1600/100 and 2000/100 mg, in HIV-positive patients.

Methods

Eighteen HIV-infected adults treated with the standard twice-daily SQV/RTV 1000/100 mg regimen were enrolled in this open-label, two-phase, crossover pharmacokinetic study. The steady-state pharmacokinetics of SQV administered with 100 mg RTV were investigated following once-daily doses of 1600 mg or 2000 mg or a twice-daily dose of 1000 mg. Plasma drug concentrations were determined by high performance liquid chromatography–tandem mass spectrometry and pharmacokinetic parameters were calculated using a non-compartmental model.

Results

Compared with SQV 1000 mg twice daily, the Cmax of SQV following a 1600 mg and 2000 mg dose increased in a dose-proportional manner [geometric mean (95% CI) 1915 (1656–2850) ng/ml for 1000 mg, 2782 (2249–4330) ng/ml for 1600 mg and 4179 (3429–6105) ng/ml for 2000 mg doses, respectively]. SQV Ctrough values were 539 (453–1011), 106 (76–223) and 231 (75–822) ng/ml, respectively. A SQV Ctrough value greater than 100 ng/ml was achieved in all subjects on the twice-daily regimen, in 9/18 (50%) subjects on the 1600/100 mg once-daily regimen, and in 14/17 (82%) subjects on the 2000/100 mg once-daily regimen. The once-daily regimens were well tolerated, with mild-to-moderate gastrointestinal symptoms being the only events reported by a small number of patients.

Conclusion

This is the first study to evaluate the pharmacokinetics of once-daily SQV/RTV 2000/100 mg in HIV-infected subjects. Our findings suggest that this regimen may be an alternative to twice-daily 1000/100 mg doses and should be further evaluated in efficacy studies. The data indicate that most patients (14/17) on once-daily 2000/100 mg achieve trough concentrations above target values (determined for HIV wild-type) for efficacy of SQV with the use of just 100 mg RTV/day and with good tolerability.

Interventions for improving adherence to treatment in patients with high blood pressure in ambulatory settings

BACKGROUND

Lack of adherence to blood pressure lowering medication is a major reason for poor control of hypertension worldwide. Interventions to improve adherence to antihypertensive medication have been evaluated in randomised trials but it is unclear which interventions are effective.

OBJECTIVES

To determine the effectiveness of interventions aiming to increase adherence to blood pressure lowering medication in adults with high blood pressure

SEARCH STRATEGY

All-language search of all articles (any year) in the Cochrane Controlled Trials Register (CCTR), MEDLINE, EMBASE, and CINAHL in April 2002.

SELECTION CRITERIA

RCTs of interventions to increase adherence to blood pressure lowering medication in adults with essential hypertension in primary care, with adherence to medication and blood pressure control as outcomes

DATA COLLECTION AND ANALYSIS

Two authors extracted data independently and in duplicate and assessed each study according to the criteria outlined by the Cochrane Collaboration Handbook.

MAIN RESULTS

We included 38 studies testing 58 different interventions and containing data on 15519 patients. The studies were conducted in nine countries between 1975 and 2000. The duration of follow-up ranged from two to 60 months. Due to heterogeneity between studies in terms of interventions and the methods used to measure adherence, we did not pool the results. Simplifying dosing regimens increased adherence in seven out of nine studies, with a relative increase in adherence of 8 per cent to 19.6 per cent. Motivational strategies were successful in 10 out of 24 studies with generally small increases in adherence up to a maximum of 23 per cent. Complex interventions involving more than one technique increased adherence in eight out of 18 studies, ranging from 5 per cent to a maximum of 41 per cent. Patient education alone seemed largely unsuccessful.

REVIEWERS' CONCLUSIONS

Reducing the number of daily doses appears to be effective in increasing adherence to blood pressure lowering medication and should be tried as a first line strategy, although there is less evidence of an effect on blood pressure reduction. Some motivational strategies and complex interventions appear promising, but we need more evidence on their effect through carefully designed RCTs.

Effect of amlodipine on systolic blood pressure

BACKGROUND

Systolic hypertension is the most common form of hypertension, particularly in people aged >60 years. Caused by decreased compliance of large arteries, systolic hypertension is an independent risk factor for cardiovascular disease. Recent studies have demonstrated that it is more important to control systolic blood pressure (SBP) than diastolic blood pressure (DBP).

OBJECTIVE

The objective of this study was to perform a systematic literature review to examine the effectiveness of amlodipine in lowering SBP in a variety of patient subgroups and clinical settings.

METHODS

The literature review methodology included identifying, selecting, appraising, extracting, and synthesizing primary research studies. Following an a priori protocol, published literature was searched from 1980 to 2001 using 3 electronic databases. A manual review of the reference lists of recent review articles and all accepted studies was performed. Parallel-group, randomized, controlled trials that included at least 10 adults with baseline hypertension (SBP>or=140 mm Hg, DBP>or=90 mm Hg, or both), included at least 1 arm randomized to initial treatment with amlodipine monotherapy, had a minimum treatment duration of 8 weeks, and reported baseline and end-point blood pressure were included.

RESULTS

Of 696 citations identified, 85 primary studies met all inclusion criteria. Comparable treatment arms were pooled, and weightd mean SBP was calculated. In the amlodipine monotherapy arms, which included >5000 patients, SBP decreased by a mean of 17.5 mm Hg from baseline. The effect of amlodipine in reducing SBP was greater in elderly patients (age>or=60 years) and patients with author-defined isolated systolic hypertension. The dose was titrated to achieve the target blood pressure in 73 of 89 amlodipine treatment arms, whereas 16 treatment arms reported fixed doses. The median daily dose was 5 mg (range, 1.25-15 mg) in both the fixed-dose and dose-titration groups.

CONCLUSIONS

In this review of the published literature, amlodipine monotherapy was effective in reducing SBP. Antihypertensive agents such as amlodipine warrant consideration for the management of patients with inadequately controlled SBP.

Some economic consequences of noncompliance

The twin problems of poor compliance and poor persistence with prescribed antihypertensive drug regimens appear to be responsible for much of the huge shortfall in the proportion of hypertensives whose treatment brings their blood pressure down to satisfactory levels. A further problem is the confounding of nonresponse and poor compliance in patients with "drug-resistant hypertension," in that about half of such patients are poor compliers, whose response to simple regimens usually proves satisfactory once their compliance with prescribed regimens is corrected. Electronic means for compiling ambulatory patients' drug dosing histories have now made it both technically and economically feasible to distinguish clearly between noncompliers and nonresponders, which clinical judgment cannot do because it is no better at making this crucial distinction than a coin toss. With the advent of reliable, economical measurements of patient compliance with prescribed drug dosing regimens, we can probably eliminate most of the compliance problems. The problem awaiting us after that is poor persistence with prescribed regimens for antihypertensive and other cardiovascular medicines that are meant for long-term or life-long use. A recent study has shown that median persistence with fully reimbursed drugs of the statin class is only 6 months, which is about one fortieth of the length it should be to realize full benefits of such therapy.

A systematic review of the associations between dose regimens and medication compliance

BACKGROUND

Previous reviews of the literature on medication compliance have confirmed the inverse relationship between number of daily doses and rate of compliance. However, compliance in most of these studies was based on patient self-report, blood-level monitoring, prescription refills, or pill count data, none of which are as accurate as electronic monitoring (EM).

OBJECTIVE

In this paper, we review studies in which compliance was measured with an EM device to determine the associations between dose frequency and medication compliance.

METHODS

Articles included in this review were identified through literature searches of MEDLINE, PsychInfo, HealthStar, Health & Psychosocial Instruments, and the Cochrane Library using the search terms patient compliance, patient adherence, electronic monitoring, and MEMS (medication event monitoring systems). The review was limited to studies reporting compliance measured by EM devices, the most accurate compliance assessment method to date. Because EM was introduced only in 1986, the literature search was restricted to the years 1986 to 2000. In the identified studies, data were pooled to calculate mean compliance with once-daily, twice-daily, 3-times-daily, and 4-times-daily dosing regimens. Because of heterogeneity in definitions of compliance, 2 major categories of compliance rates were defined: dose-taking (taking the prescribed number of pills each day) and dose-timing (taking pills within the prescribed time frame).

RESULTS

A total of 76 studies were identified. Mean dose-taking compliance was 71% +/- 17% (range, 34%-97%) and declined as the number of daily doses increased: 1 dose = 79% +/- 14%, 2 doses = 69% +/- 15%, 3 doses = 65% +/- 16%, 4 doses = 51% +/- 20% (P < 0.001 among dose schedules). Compliance was significantly higher for once-daily versus 3-times-daily (P = 0.008), once-daily versus 4-times-daily (P < 0.001), and twice-daily versus 4-times-daily regimens (P = 0.001); however, there were no significant differences in compliance between once-daily and twice-daily regimens or between twice-daily and 3-times-daily regimens. In the subset of 14 studies that reported dose-timing results, mean dose-timing compliance was 59% +/- 24%; more frequent dosing was associated with lower compliance rates.

CONCLUSIONS

A review of studies that measured compliance using EM confirmed that the prescribed number of doses per day is inversely related to compliance. Simpler, less frequent dosing regimens resulted in better compliance across a variety of therapeutic classes.

Cardiovascular risk and therapeutic intervention for the early morning surge in blood pressure and heart rate

The incidence of most adverse cardiovascular events appears to follow a circadian pattern, reaching a peak in the morning shortly after wakening and arising. The activities of many physiologic parameters, including hemodynamic, hematologic and humoral factors, also fluctuate in a cyclical manner over the 24h. It has been suggested that, during the post-awakening hours, the phases of these cycles synchronize to create an environment that predisposes to atherosclerotic plaque rupture and thrombosis in susceptible individuals, thereby accounting for the heightened cardiovascular risk at this time of day. Blood pressure and heart rate are part of this physiologic process, following a clear circadian rhythm characterized by a fall during sleep and a sharp rise upon awakening. This so-called 'morning surge' in blood pressure may act as a trigger for cardiovascular events, including myocardial infarction and stroke. The clinical implication of these observations is that antihypertensive therapy should provide blood pressure control over the entire interval between doses. For agents taken once daily in the morning, the time of trough plasma drug level (and lowest pharmacodynamic effect) will often coincide with the early morning surge in blood pressure and heart rate. For these reasons, chronotherapeutic formulations of drugs and intrinsically long-acting antihypertensive agents provide the most logical approach to the treatment of hypertensive patients since they provide 24 h blood pressure control from a single daily dose as well as attenuating the early morning rise in blood pressure (and in some instances heart rate).

Hypertension and current issues in compliance and patient outcomes

Economic and human costs associated with untreated or inadequately controlled hypertension and its complications continue to be an issue in the United States despite the availability of numerous antihypertensive agents. Knowledge of hypertension, product profiles, tolerability concerns, convenience of dosing, health-related quality of life effects, and cost of therapy are some of the factors that may influence the compliance of patients to their medication regimens. Recent reports on patient noncompliance have focused on patient-provider relationships, psychosocial barriers, home blood pressure monitoring, and electronic monitoring systems to improve blood pressure control. The use of health-related quality of life assessment in antihypertensive studies and in routine clinical practice provides another opportunity to optimize a patient's regimen for short- and long-term hypertension control in a cost-effective manner.