Twenty-four hour ambulatory blood pressure in the International Nifedipine GITS Study Intervention as a Goal in Hypertension Treatment (INSIGHT)

First-line diuretics versus other classes of antihypertensive drugs for hypertension

BACKGROUND

Different first-line drug classes for patients with hypertension are often assumed to have similar effectiveness with respect to reducing mortality and morbidity outcomes, and lowering blood pressure. First-line low-dose thiazide diuretics have been previously shown to have the best mortality and morbidity evidence when compared with placebo or no treatment. Head-to-head comparisons of thiazides with other blood pressure-lowering drug classes would demonstrate whether there are important differences.

OBJECTIVES

To compare the effects of first-line diuretic drugs with other individual first-line classes of antihypertensive drugs on mortality, morbidity, and withdrawals due to adverse effects in patients with hypertension. Secondary objectives included assessments of the need for added drugs, drug switching, and blood pressure-lowering.

SEARCH METHODS

Cochrane Hypertension's Information Specialist searched the Cochrane Hypertension Specialized Register, CENTRAL, MEDLINE, Embase, and trials registers to March 2021. We also checked references and contacted study authors to identify additional studies. A top-up search of the Specialized Register was carried out in June 2022.

SELECTION CRITERIA

Randomized active comparator trials of at least one year's duration were included. Trials had a clearly defined intervention arm of a first-line diuretic (thiazide, thiazide-like, or loop diuretic) compared to another first-line drug class: beta-blockers, calcium channel blockers, alpha adrenergic blockers, angiotensin converting enzyme (ACE) inhibitors, angiotensin II receptor blockers, direct renin inhibitors, or other antihypertensive drug classes. Studies had to include clearly defined mortality and morbidity outcomes (serious adverse events, total cardiovascular events, stroke, coronary heart disease (CHD), congestive heart failure, and withdrawals due to adverse effects).

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methodological procedures.

MAIN RESULTS

We included 20 trials with 26 comparator arms randomizing over 90,000 participants. The findings are relevant to first-line use of drug classes in older male and female hypertensive patients (aged 50 to 75) with multiple co-morbidities, including type 2 diabetes. First-line thiazide and thiazide-like diuretics were compared with beta-blockers (six trials), calcium channel blockers (eight trials), ACE inhibitors (five trials), and alpha-adrenergic blockers (three trials); other comparators included angiotensin II receptor blockers, aliskiren (a direct renin inhibitor), and clonidine (a centrally acting drug). Only three studies reported data for total serious adverse events: two studies compared diuretics with calcium channel blockers and one with a direct renin inhibitor. Compared to first-line beta-blockers, first-line thiazides probably result in little to no difference in total mortality (risk ratio (RR) 0.96, 95% confidence interval (CI) 0.84 to 1.10; 5 trials, 18,241 participants; moderate-certainty), probably reduce total cardiovascular events (5.4% versus 4.8%; RR 0.88, 95% CI 0.78 to 1.00; 4 trials, 18,135 participants; absolute risk reduction (ARR) 0.6%, moderate-certainty), may result in little to no difference in stroke (RR 0.85, 95% CI 0.66 to 1.09; 4 trials, 18,135 participants; low-certainty), CHD (RR 0.91, 95% CI 0.78 to 1.07; 4 trials, 18,135 participants; low-certainty), or heart failure (RR 0.69, 95% CI 0.40 to 1.19; 1 trial, 6569 participants; low-certainty), and probably reduce withdrawals due to adverse effects (10.1% versus 7.9%; RR 0.78, 95% CI 0.71 to 0.85; 5 trials, 18,501 participants; ARR 2.2%; moderate-certainty). Compared to first-line calcium channel blockers, first-line thiazides probably result in little to no difference in total mortality (RR 1.02, 95% CI 0.96 to 1.08; 7 trials, 35,417 participants; moderate-certainty), may result in little to no difference in serious adverse events (RR 1.09, 95% CI 0.97 to 1.24; 2 trials, 7204 participants; low-certainty), probably reduce total cardiovascular events (14.3% versus 13.3%; RR 0.93, 95% CI 0.89 to 0.98; 6 trials, 35,217 participants; ARR 1.0%; moderate-certainty), probably result in little to no difference in stroke (RR 1.06, 95% CI 0.95 to 1.18; 6 trials, 35,217 participants; moderate-certainty) or CHD (RR 1.00, 95% CI 0.93 to 1.08; 6 trials, 35,217 participants; moderate-certainty), probably reduce heart failure (4.4% versus 3.2%; RR 0.74, 95% CI 0.66 to 0.82; 6 trials, 35,217 participants; ARR 1.2%; moderate-certainty), and may reduce withdrawals due to adverse effects (7.6% versus 6.2%; RR 0.81, 95% CI 0.75 to 0.88; 7 trials, 33,908 participants; ARR 1.4%; low-certainty). Compared to first-line ACE inhibitors, first-line thiazides probably result in little to no difference in total mortality (RR 1.00, 95% CI 0.95 to 1.07; 3 trials, 30,961 participants; moderate-certainty), may result in little to no difference in total cardiovascular events (RR 0.97, 95% CI 0.92 to 1.02; 3 trials, 30,900 participants; low-certainty), probably reduce stroke slightly (4.7% versus 4.1%; RR 0.89, 95% CI 0.80 to 0.99; 3 trials, 30,900 participants; ARR 0.6%; moderate-certainty), probably result in little to no difference in CHD (RR 1.03, 95% CI 0.96 to 1.12; 3 trials, 30,900 participants; moderate-certainty) or heart failure (RR 0.94, 95% CI 0.84 to 1.04; 2 trials, 30,392 participants; moderate-certainty), and probably reduce withdrawals due to adverse effects (3.9% versus 2.9%; RR 0.73, 95% CI 0.64 to 0.84; 3 trials, 25,254 participants; ARR 1.0%; moderate-certainty). Compared to first-line alpha-blockers, first-line thiazides probably result in little to no difference in total mortality (RR 0.98, 95% CI 0.88 to 1.09; 1 trial, 24,316 participants; moderate-certainty), probably reduce total cardiovascular events (12.1% versus 9.0%; RR 0.74, 95% CI 0.69 to 0.80; 2 trials, 24,396 participants; ARR 3.1%; moderate-certainty) and stroke (2.7% versus 2.3%; RR 0.86, 95% CI 0.73 to 1.01; 2 trials, 24,396 participants; ARR 0.4%; moderate-certainty), may result in little to no difference in CHD (RR 0.98, 95% CI 0.86 to 1.11; 2 trials, 24,396 participants; low-certainty), probably reduce heart failure (5.4% versus 2.8%; RR 0.51, 95% CI 0.45 to 0.58; 1 trial, 24,316 participants; ARR 2.6%; moderate-certainty), and may reduce withdrawals due to adverse effects (1.3% versus 0.9%; RR 0.70, 95% CI 0.54 to 0.89; 3 trials, 24,772 participants; ARR 0.4%; low-certainty). For the other drug classes, data were insufficient. No antihypertensive drug class demonstrated any clinically important advantages over first-line thiazides.

AUTHORS' CONCLUSIONS

When used as first-line agents for the treatment of hypertension, thiazides and thiazide-like drugs likely do not change total mortality and likely decrease some morbidity outcomes such as cardiovascular events and withdrawals due to adverse effects, when compared to beta-blockers, calcium channel blockers, ACE inhibitors, and alpha-blockers.

Methods of Blood Pressure Assessment Used in Milestone Hypertension Trials

In the present review, we summarized the blood pressure (BP) measurement protocols of contemporary outcome trials in hypertension. In all these trials, clinic BP was used for the diagnosis and therapeutic monitoring of hypertension. In most trials, BP was measured in the sitting position with mercury sphygmomanometers or automated electronic BP monitors by trained observers. BP readings were taken on each occasion at least twice with a 30-to-60-s interval after 5 min of rest. Details regarding the arm side, cuff size, and the timing of BP measurement were infrequently reported. If clinic BP continues being used in future hypertension trials, the measurement should strictly follow current guidelines. The observers must be trained and experienced, and the device should be validated by automated electronic BP monitors. On each occasion, BP readings should be taken 2-3 times. The time interval between successive measurements has to be 30-60 s, and the resting period before the measurement should be at least 5 min in the supine or seated position and 1-3 min standing. BP should usually be measured in the seated position. The higher arm side and an appropriate size cuff should be chosen and noted. BP should be measured at defined trough hours. Automated office BP measurement has recently been used and seems to have less white-coat effect. The out-of-office BP measurement, either ambulatory or home BP monitoring, was only used in a subset of study participants of few hypertension trials. Future trials should consider these novel office or out-of-office BP measurements in guiding the therapy and preventing cardiovascular events.

Nifedipine gastrointestinal therapeutic system (GITS) in the treatment of coronary heart disease and hypertension

Since the 1960s, calcium antagonists have been available for the treatment of angina pectoris and hypertension. The first of this class, nifedipine, was introduced and readily accepted as the third treatment option for angina, alongside beta-blockers and nitrates. However, the short-acting formulations of nifedipine had pharmacokinetic properties that were far from ideal and in 1995, several studies involving various dosing regimens reported possible dangerous effects in secondary prevention. Since then, large-scale, randomized controlled trials with new controlled-released formulations of nifedipine have demonstrated the effectiveness and safety of this drug. As a consequence of these results, guidelines for both hypertension and angina pectoris have been recently reconsidered, and have put the modern formulations of calcium channel blockers in a pole position. Within this group of therapeutics, nifedipine gastrointestinal therapeutic system has a unique position and it cannot be replaced by other controlled-release formulations of nifedipine, the pharmaceutical properties of which have yet to be tested in large-scale outcome trials.

Ambulatory Blood Pressure Values in the Ongoing Telmisartan Alone and in Combination with Ramipril Global Endpoint Trial (ONTARGET)

In the Ongoing Telmisartan Alone and in Combination with Ramipril Global Endpoint Trial, telmisartan (T; 80 mg daily) and ramipril (R; 10 mg daily) caused similar clinic blood pressure (BP) reductions, with a similar incidence of cardiovascular and renal events. The R+T combination lowered clinic BP somewhat more with no further cardiovascular or renal protection. The aim of this substudy was to see whether these clinic BP changes reflected the changes of 24-hour BP, a BP with a better prognostic value. In 422 patients in whom 24-hour BP monitoring was performed either before or after 6 to 24 months of treatment, demographic and clinical characteristics were similar in the 3 treated groups. Twenty-four-hour systolic BP was similarly reduced by R (−2.0 mm Hg) and T (−2.1 mm Hg), whereas the reduction was more than twice as large in the T+R group (−5.3 mm Hg), which showed a lower on-treatment 24-hour BP also in additional patients (n=408) in whom ambulatory BP was performed only on-treatment. Twenty-four-hour systolic BP was ≈14 mm Hg lower than clinic systolic BP at baseline, whereas during treatment the 2 values became progressively closer as clinic systolic BP was more tightly controlled and superimposable when clinic systolic BP was <120 mm Hg. Similar results were obtained for diastolic BP. These findings provide evidence on the relationship of clinic and ambulatory BP target drug treatment. They also show that in the Ongoing Telmisartan Alone and in Combination with Ramipril Global Endpoint Trial, failure of the R+T combination to enhance cardiovascular and renal protection was not because of inability to more effectively control daily life BP.

Administration-time differences in effects of hypertension medications on ambulatory blood pressure regulation

Specific features of the 24-h blood pressure (BP) pattern are linked to progressive injury of target tissues and risk of cardiovascular disease (CVD) events. Several studies have consistently shown an association between blunted asleep BP decline and risk of fatal and nonfatal CVD events. Thus, there is growing focus on ways to properly control BP during nighttime sleep as well as during daytime activity. One strategy, termed chronotherapy, entails the timing of hypertension medications to endogenous circadian rhythm determinants of the 24-h BP pattern. Significant and clinically meaningful treatment-time differences in the beneficial and/or adverse effects of at least six different classes of hypertension medications, and their combinations, are now known. Generally, calcium channel blockers (CCBs) are more effective with bedtime than morning dosing, and for dihydropyridine derivatives bedtime dosing significantly reduces risk of peripheral edema. The renin-angiotensin-aldosterone system is highly circadian rhythmic and activates during nighttime sleep. Accordingly, evening/bedtime ingestion of the angiotensin-converting enzyme inhibitors (ACEIs) benazepril, captopril, enalapril, lisinopril, perindopril, quinapril, ramipril, spirapril, trandolapril, and zofenopril exerts more marked effect on the asleep than awake systolic (SBP) and diastolic (DBP) BP means. Likewise, the bedtime, in comparison with morning, ingestion schedule of the angiotensin-II receptor blockers (ARBs irbesartan, olmesartan, telmisartan, and valsartan exerts greater therapeutic effect on asleep BP, plus significant increase in the sleep-time relative BP decline, with the additional benefit, independent of drug terminal half-life, of converting the 24-h BP profile into a more normal dipping pattern. This is the case also for the bedtime versus upon-awakening regimen of combination ARB-CCB, ACEI-CCB, and ARB-diuretic medications. The chronotherapy of conventional hypertension medications constitutes a new and cost-effective strategy for enhancing the control of daytime and nighttime SBP and DBP levels, normalizing the dipping status of their 24-h patterning, and potentially reducing the risk of CVD events and end-organ injury, for example, of the blood vessels and tissues of the heart, brain, kidney, and retina.

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.

Reduction of morning blood pressure surge after treatment with nifedipine GITS at bedtime, but not upon awakening, in essential hypertension

OBJECTIVES

The extent of morning blood pressure (BP) surge upon wakening has been associated with increased incidence of stroke and cardiovascular mortality. This trial investigated the antihypertensive efficacy and effects on the morning BP surge of awakening versus bedtime administration of nifedipine in essential hypertension.

METHODS

We studied 238 previously untreated hypertensive patients (108 men and 130 women), 53.3+/-11.4 years of age, randomly assigned to receive nifedipine (30 mg/day) as a monotherapy either upon awakening or at bedtime. BP was measured for 48 h before and after 8 weeks of treatment.

RESULTS

The BP reduction after the treatment was significantly greater with bedtime dosing (P<0.001). The proportion of patients with controlled ambulatory BP thus increased from 28 to 43% (P = 0.019) with bedtime treatment. The sleep time relative BP decline was unchanged after morning treatment, but increased toward a more dipping pattern after bedtime dosing (P = 0.026 between groups). The morning BP surge was unchanged after the administration of nifedipine upon awakening (1.4/1.2 mmHg reduction in systolic/diastolic BP surge, P>0.270), but significantly reduced after bedtime dosing (6.2/4.4 mmHg reduction, P<0.001).

CONCLUSION

Nifedipine efficiently reduces BP for the entire 24 h and to a significantly larger extent after bedtime administration. The significant added efficacy on reducing night-time BP, the decrease in the prevalence of a nondipper BP pattern, and the significant decrease in morning BP surge (all relevant markers of cardiovascular morbidity and mortality) of bedtime as compared with morning administration, consistently indicate that nifedipine should preferably be administered at bedtime in patients with essential hypertension.

Clinical utility and applicability of smoothness index, normalized smoothness index and individualized RDH index during treatment of essential hypertension

The purpose of this study was to assess the clinical utility of the smoothness index (SI) and normalized SI (SIn), measures of duration and homogeneity of blood pressure (BP) reduction, during an observation period without antihypertensive therapy followed by a treatment period using dihydropyridines (DHP) in 54 newly diagnosed and previously untreated subjects (age 46.9 +/- 9.1 years) with essential hypertension. In addition, we aimed to describe the reduction-duration-homogeneity (RDH) index for statistical assessment of the BP reduction in the individual patient. Twenty-four-hour BP was lowered during treatment (139.2 +/- 13.9/ 91.0 +/- 7.6 mmHg vs 130.9 +/- 11.3/85.2 +/- 5.2 mmHg, p < 0.001/p = 0.001). SI showed great interindividual variation, and increased from zero to 0.9 +/- 0.8 (systolic BP) and 0.8 +/- 0.7 (diastolic BP) after treatment (p < 0.001 for both), similar results were obtained for SI(n). The RDH index revealed BP reduction in agreement with the change in individual 24-h, daytime and night-time BP. Although SI and SI(n) may add important information regarding the homogeneity of the antihypertensive effect in a group of patients, and the RDH index for the individual patient, conclusions regarding antihypertensive efficacy can be obtained from assessment of the 24-h, daytime and night-time BP changes and ambulatory BP profiles. Based on our findings, we do not recommend the use of SI or RDH index in the clinical practice.

Dose‐ And Administration Time‐Dependent Effects Of Nifedipine Gits On Ambulatory Blood Pressure In Hypertensive Subjects

Previous chronotherapy studies have shown that the circadian pattern of blood pressure (BP) remains unchanged after either morning or evening dosing of several calcium channel blockers (CCB), including amlodipine, isradipine, verapamil, nitrendipine, and cilnidipine. This trial investigated the antihypertensive efficacy and safety profile of the slow-release, once-a-day nifedipine gastrointestinal therapeutic system (GITS) formulation administered at different times with reference to the rest-activity cycle of each participant. We studied 80 diurnally active subjects (36 men and 44 women), 52.1+/-10.7 yrs of age, with grade 1-2 essential hypertension, who were randomly assigned to receive nifedipine GITS (30 mg/day) as a monotherapy for eight weeks, either upon awakening in the morning or at bedtime at night. Patients with uncontrolled BP were up-titrated to a higher dose, 60 mg/day nifedipine GITS, for an additional eight weeks. BP was measured by ambulatory monitoring every 20 min during the day and every 30 min at night for 48 consecutive hours before and after therapy with either dose. The BP reduction after eight weeks of therapy with the lower dose of 30 mg/day was slightly, but not significantly, larger with bedtime dosing. The efficacy of 60 mg/day nifedipine GITS in non-responders to the initial 30 mg/day dose was twice as great with bedtime as compared to morning dosing. Moreover, bedtime administration of nifedipine GITS reduced the incidence of edema as an adverse event by 91%, and the total number of all adverse events by 74% as compared to morning dosing (p=0.026). Independent of the time of day of administration, a single daily dose of 30 mg/day of nifedipine GITS provides full 24 h therapeutic coverage. The dose-dependent increased efficacy and the markedly improved safety profile of bedtime as compared to morning administration of nifedipine GITS should be taken into account when prescribing this CCB in the treatment of essential hypertension.

Chronotherapy with nifedipine GITS in hypertensive patients: improved efficacy and safety with bedtime dosing

BACKGROUND

Previous studies have shown that the circadian pattern of blood pressure (BP) remains unchanged after either morning or evening dosing of several calcium-channel blockers (CCBs), including amlodipine, isradipine, verapamil, nitrendipine, and cilnidipine. This trial investigated the administration-time dependent antihypertensive efficacy of the slow-release, once-a-day nifedipine gastrointestinal-therapeutic-system (GITS) formulation.

METHODS

We studied 180 untreated hypertensives (86 men and 94 women), 52.5 +/- 10.7 years of age, randomly assigned to receive nifedipine (30 mg/day) as a monotherapy either upon awakening or at bedtime. BP was measured for 48 h before and after 8 weeks of treatment.

RESULTS

The BP reduction after treatment was significantly larger with bedtime dosing mainly during night time sleep (P < 0.012). The number of patients with controlled ambulatory BP after treatment was greater with bedtime than morning treatment (P = 0.016). The baseline prevalence of nondipping was unaltered after ingestion of nifedipine on awakening, but reduced from 51 to 35% after bedtime dosing (P = 0.025). The morning surge of BP, a risk factor for stroke, was significantly reduced (P < 0.001) only after bedtime administration of nifedipine. Bedtime in comparison to awakening-time ingestion of nifedipine was also associated with a reduction in the incidence of edema from 13 to 1% (P < 0.001).

CONCLUSIONS

The increased efficacy on ambulatory BP as well as the significantly reduced prevalence of edema after bedtime as compared to morning ingestion of nifedipine should be taken into account when prescribing this medication to patients with essential hypertension.

Long-acting nifedipine in the management of the hypertensive patient

Hypertension is a global condition affecting billions worldwide. It is a significant contributor to cardiovascular events, cardiac death and kidney disease. A number of medication classes exist to aid healthcare providers and their patients in controlling hypertension. Nifedipine, a dihydropyridine calcium channel blocker, was once one of the most widely used medications for hypertension, but safety and tolerability concerns along with the introduction of new classes of antihypertensive medications and an increasing pool of data showing mortality benefit of other classes caused nifedipine to fall out of favor. More recently, long-acting formulations were developed and made available to clinicians. These newer formulations were designed to address many of the concerns raised by earlier formulations of nifedipine. Numerous clinical trials have been conducted comparing long-acting nifedipine to many of the more commonly prescribed antihypertensive medications. This review will address the pharmacology, pharmacokinetics and the available clinical trial data on long-acting nifedipine and summarize its role in the management of hypertension.

A double-blind, controlled, multicenter, randomized study comparing the antihypertensive effectiveness and tolerance of a daily dose of two nifedipine formulations: nifedipine microgranules versus nifedipine osmotic pump

INTRODUCTION

Controlled clinical studies have clearly established the advantages of blood pressure (BP) reduction. However, optimal control of BP in the population is still not adequate. Monotherapy is ineffective in the majority of hypertensive patients, and multidrug therapy increases costs.

OBJECTIVE

The objective of the study was to assess to what extent and how uniformly BP can be controlled with two different 24-hour drug-releasing formulations of nifedipine, used as monotherapy.

METHODS

One hundred ninety-two patients of both genders, aged 18 to 65 years, with mild to moderate (Stage 1 and 2) essential hypertension with systolic BP <200 mm Hg and diastolic BP between 90 and 115 mm Hg were randomized in a double-blind, double-dummy fashion to receive sustained-release formulations of 30 mg nifedipine/day either as microgranules (NMG) or via osmotic pump (NOP) for 8 weeks. Office BP was measured at baseline (after 2 weeks of placebo) and after the third to fourth week of treatment. If at the third to fourth week the systolic BP/diastolic BP did not reach values of <140/<90 mm Hg, the dose was doubled to 60 mg/day. Monotherapy that did not yield these BP values at 8 weeks was considered a failure. Ambulatory monitoring of blood pressure (AMBP) was also performed after the placebo period and at the end of treatment. Smoothness index (SI) and trough/peak ratio (T/P) were calculated and their correlation was checked.

RESULTS

The initial systolic/diastolic BP values were similar at baseline and decreased significantly after the third to fourth week of treatment, with no difference between the groups. The proportions of patients reaching the goal BP (<140/<90 mm Hg) were similar in the two groups: NMG, 71%, and NOP, 78% (P = 0.12). There were no changes in the heart rate in either group. There was no difference between groups in the reduction in mean arterial pressure measured by AMBP. The frequency of SI values >1.4 and T/P ratios of >0.5 was similar in both groups. An important correlation was found between the SI and T/P values. The incidence of adverse effects was low and similar in both groups.

CONCLUSIONS

Target BP was reached in more than 70% of patients receiving monotherapy with either formulation. Both formulations were tolerated well.

Ambulatory blood pressure monitoring after 1 year on valsartan or amlodipine-based treatment: a VALUE substudy

OBJECTIVE

The ambulatory blood pressure (ABP) monitoring substudy of the Valsartan Antihypertensive Long-term Use Evaluation (VALUE) trial was carried out in a subset of patients from USA, Italy and Denmark. ABP was measured after 1 year in the trial, with the aim of evaluating comparability of ABP levels on valsartan (VAL) and amlodipine (AML)-based regimens.

METHODS

ABP was measured every 20 min during a 25-h period after morning administration of medicine; 659 patients were available for intention-to-treat analysis.

RESULTS

Office blood pressure (BP) differences were smaller than in the main study and mean ABP levels also showed only minor differences between the two regimens (VAL, 132.5/74.8 mmHg; AML, 131.5/75.2 mmHg). However, during the first 7 h after dosing, ABP was lower on VAL, whereas AML exerted a significantly stronger effect during the last 4 h of the dosing interval--possibly influencing the differences in office BP found in the main study. Mean heart rate (HR) was higher on AML (72.3 bpm) than on VAL (70.5 bpm) (P = 0.013), suggesting a sustained difference in sympathetic activation. Correlation analysis showed a close relationship between treated ABP levels and the occurrence of combined cardiovascular endpoints--superior to the relationship to office BP.

CONCLUSIONS

In these elderly high-risk patients, diastolic ABP levels tended to be less predictive than systolic, and daytime less predictive than night-time for all cardiovascular endpoints. The findings underline the importance of ABP substudies in comparative trials for elucidating significant differences in pharmacodynamics, and stresses the superior predictive power of ABP.

Modified-release nifedipine: a review of the use of modified-release formulations in the treatment of hypertension and angina pectoris

Nifedipine is a dihydropyridine calcium channel antagonist with predominantly vasodilatory activity. Modified-release formulations of nifedipine are effective antihypertensive and antianginal therapies and are generally well tolerated. Among the available formulations, those that produce a gradual increase in plasma nifedipine concentration, which is then sustained over a 24-hour period, are preferred, as they cause a gradual onset of vasodilatation and avoid baroreflex sympathetic activation (for example, nifedipine gastrointestinal therapeutic system [GITS] and a Japanese controlled-release formulation). Modified-release nifedipine had beneficial effects on a number of markers of vascular function, and nifedipine GITS reduced the need for coronary procedures in patients with coronary artery disease. In patients with hypertension, nifedipine GITS and nifedipine retard had beneficial effects on the overall incidence of major cardiovascular events, as did nifedipine retard in patients with concurrent hypertension and coronary artery disease.

The population RDH index: a novel vector index and graphical method for statistical assessment of antihypertensive treatment reduction, duration, and homogeneity

Current indices used in the evaluation of antihypertensive treatment duration and homogeneity such as the trough-peak, smoothness index, and normalized smoothness index were designed to be applied to ambulatory blood pressure monitoring recordings from individual participants. Evaluation of antihypertensive treatment in populations is often carried out by calculating these individual indices for each of the participants and providing summarizing statistics about the population, such as the mean and median. We describe a new population vector index and graphical method for the statistical assessment of antihypertensive treatment reduction, duration, and homogeneity (RDH) from ambulatory blood pressure monitoring. The population (RDH) was specifically designed as a tool to evaluate and compare blood pressure coverage offered by antihypertensive drugs over 24 h in populations. The population RDH is a three-component vector index that incorporates information about the reduction, duration, and homogeneity of antihypertensive treatment, as well as their statistical significance over the 24 h period. In addition to defining the RDH index, in this paper we also demonstrate its usefulness and advantages as an index and graphical method for antihypertensive treatment duration and homogeneity assessment by using it to analyze two data sets.

Nifedipine gastrointestinal therapeutic system--hypertension management to improve cardiovascular outcomes

Hypertension is a major cardiovascular risk factor, and its increasing prevalence is of great clinical concern. Despite the availability of numerous effective therapies, hypertension remains under-diagnosed and under-treated. Hypertension often coexists with other risk factors, and current guidelines recommend a multifactorial approach to management, with the aim of not only controlling blood pressure but also reducing overall cardiovascular risk. Nifedipine gastrointestinal therapeutic system (GITS) is a long-acting formulation of a calcium channel blocker. Once-daily dosing with nifedipine GITS has been shown to achieve smooth and continuous blood pressure control, identical to conventional first-line diuretic therapy. Small-scale clinical trials have also shown that nifedipine GITS positively affects markers of atherosclerotic disease, which may signify an additional clinical benefit, but this is yet to be demonstrated. The recently completed ACTION (A Coronary Disease Trial Investigating Outcome with Nifedipine GITS) trial provides further evidence that nifedipine GITS can be used safely in high-risk patients to treat angina, lower blood pressure and significantly improve clinical outcomes.

Utility of 24-h ambulatory blood pressure measurement in a routine clinical setting of patients with chronic renal disease

The objective of the study was to investigate the utility of 24 h ambulatory blood pressure measurement (ABPM) in patients with chronic renal disease (CRD). A retrospective audit was performed in an academic nephrology department. ABPMs obtained from 95 consecutive outpatients with nondiabetic renal disease were analysed for their power to stratify disease severity and to predict progression of renal insufficiency during 3 years follow-up. The average of 10 consecutive office blood pressure (BP) readings performed at baseline was used as a reference. Correlations and tabulated statistics were calculated. Baseline mean diurnal BP was 138/87 mmHg by ABPM and 146/92 mmHg by average office BP (56.8 vs 25.3% normotensives, P < 0.01). Mean serum creatinine was 154 +/- 109 micromol/l. Patients without a circadian BP pattern (61%) had significantly higher serum creatinine, urinary albumin excretion and subsequent progression rates of renal failure (P < 0.05). Systolic and pulse pressure ABP values correlated significantly with serum creatinine levels at baseline and 3 years thereafter, independent of daytime (r = 0.23-0.60; P < 0.05). Abnormal nocturnal systolic and mean ABP, and pulse pressure but not average day office BP were significantly associated with abnormal serum creatinine and the presence of coronary heart disease at baseline (relative risk 1.6-1.7, P < 0.05). In conclusion, physicians considered ABPM preferentially in patients with borderline-controlled BP. ABPM provided significant additional information relevant to the clinical decision making process compared with average office BP alone thereby justifying its use in specific situations.

Circadian variations in blood pressure : implications for chronotherapeutics

The management of hypertensive patients usually ignores or gives little credit to the biologic rhythms inherent to the disease process and their potential clinical implications. The development of ambulatory blood pressure monitoring and the rapidly growing popularity of home blood pressure measurements by patients have now generated a series of new clinical questions that are directly linked to the chronobiology of the cardiovascular system, such as the clinical interpretation of a blunted nocturnal fall in blood pressure or the difficulty of achieving adequate blood pressure control in the morning. Today, there is growing evidence that night-time blood pressure, and particularly the absence of a decrease in sleep blood pressure, contributes to the occurrence of target organ damages, and that the early morning rise in blood pressure increases the risk of developing cardiovascular events, including stroke, perhaps independently of 24-hour blood pressure levels. On the basis of these observations, it may be necessary to reconsider the way antihypertensive drugs are prescribed in order to obtain smooth, 24-hour blood pressure control, respecting the circadian pattern of blood pressure. Several approaches exist, including the use of drugs that lower blood pressure around the clock and respect the diurnal rhythm. Preliminary studies performed with such agents have provided interesting results. However, there is a clear need for large clinical trials demonstrating the clinical superiority of this approach. In any case, a better understanding of the importance of the circadian variations of blood pressure could certainly have a major impact on our view of the therapeutic management of hypertensive patients.

Office compared with ambulatory blood pressure in assessing response to antihypertensive treatment: a meta-analysis

OBJECTIVE

To undertake a systematic review of the studies on the effect of antihypertensive treatment on ambulatory (ABP) and office blood pressure in order to obtain a differential assessment of the magnitude of the reduction in (1) office blood pressure compared with 24-h average ABP values, and (2) daytime compared with night-time average blood pressure values.

DATA SOURCES

Medline search, Cochrane Library.

REVIEW METHODS

This review is based on a meta-analysis (carried out according to the Quality of Reports of Meta-analyses of Randomized Controlled Trials Group statement, whenever applicable) of papers on the effect of antihypertensive drugs on blood pressure. Papers were selected if they provided information on drug-induced changes in one or both of: (1) both office blood pressure and 24-h ABP, and/or (2) both daytime and night-time average blood pressure. Additional inclusion criteria were administration of antihypertensive drugs for at least 1 week and good quality ABP, according to current guidelines. Comparison between the effect of treatment on blood pressure values was made by meta-regression of the data provided by the individual studies (weighted by their size) and by calculating differences between weighted average values obtained by pooling the results of individual papers.

RESULTS

We identified 984 papers on this issue by Medline search, with no additional information from the Cochrane Library. The inclusion criteria were satisfied by only 44 papers, which were included in the final analysis. The results showed that treatment-induced reduction in blood pressure is both smaller for the 24-h average than for the office systolic and diastolic blood pressure and smaller for night-time than for daytime average diastolic blood pressure, the average ratio ranging from 0.67 to 0.75. A different ratio characterized the treatment-induced changes in office blood pressure and ABP in the Heart Outcomes Prevention Evaluation (HOPE) ABP substudy.

CONCLUSIONS

The effect of antihypertensive treatment is greater on office blood pressure than on ABP, and is unevenly distributed between day and night. This suggests caution when interpreting trials on cardiovascular protection by antihypertensive treatment that are based only on office blood pressure readings, and advocates a more systematic adoption of ABP monitoring in these trials. The conflicting data provided by the main HOPE study and by the HOPE-ABP monitoring substudy on the role of blood pressure reduction in explaining the reduced event rates associated with treatment by angiotensin-converting enzyme inhibitors are a clear example of the importance of performing ABP monitoring in trials on cardiovascular protection.

Once-daily fixed-combination irbesartan 300 mg/ hydrochlorothiazide 25 mg and circadian blood pressure profile in patients with essential hypertension

BACKGROUND

More than 60% of patients with hypertension included in morbidity and mortality trials needed >or=2 drugs to achieve a substantial, sustained reduction in blood pressure. Tolerable combinations using higher doses of antihypertensive drugs are frequently required to control blood pressure.

OBJECTIVE

The goal of this study was to assess the effect of a once-daily fixed combination of irbesartan 300 mg/hydrochlorothiazide (HCTZ) 25 mg on the circadian blood pressure profile in patients with essential hypertension that was not controlled with full-dose single therapy or low-dose combined therapy.

METHODS

Study patients were recruited consecutively from the outpatient hypertension clinics of 3 university hospitals in Spain. After a 1-week washout period, patients with a mean daytime blood pressure >135/85 mm Hg were treated with irbesartan 300 mg/HCTZ 25 mg once daily for 12 weeks. Twenty-four-hour ambulatory blood pressure monitoring was performed at the end of the washout period and during the last week of treatment.

RESULTS

Fifty-seven patients with essential hypertension (28 men, 29 women) were enrolled; their mean (SD) age was 60.4 (7.2) years (range, 45-78 years). After treatment, a significant reduction in both clinic and ambulatory mean (SD) blood pressure values was observed in the whole group of 57 patients (from 146.0 [11.0] mm Hg to 123.3 [13.3] mm Hg, P < 0.001 for 24-hour systolic blood pressure [SBP]; from 89.9 [8.2] mm Hg to 76.5 [9.4] mm Hg, P < 0.001 for 24-hour diastolic blood pressure [DBP]. The mean lowering of ambulatory SBP and DBP at peak was 25.2 (14.5) mm Hg and 14.7 (9.5) mm Hg, respectively, and at trough, 22.3 (18.3) mm Hg and 12.3 (10.9) mm Hg. The trough-to-peak ratio of the group was 0.92 for SBP (0.97 in responders) and 0.84 for DBP (0.89 in responders). The smoothness index, calculated as the mean of all individual values, was 1.7 (1.0) for SBP (1.8 [0.9] in responders) and 1.3 (0.8) for DBP (1.5 [0.6] in responders). Seven side effects in 6 patients were reported. No metabolic changes were observed, and no patient discontinued the study because of treatment-related adverse effects.

CONCLUSIONS

The fixed combination of irbesartan 300 mg/HCTZ 25 administered once daily produced a crude meaningful effect in reducing 24-hour blood pressure and was well tolerated. The circadian profile was preserved, as shown by trough-to-peak ratios and smoothness index values for both SBP and DBP.

Clinical use of nifedipine GITS in the treatment of hypertension: an overview

Given the major role of elevated blood pressure in the pathogenesis of both stroke and coronary heart disease, one of the biggest challenges facing public health authorities and medical practitioners is the control of hypertension worldwide, both in individual patients and at the population level. The prevalence of hypertension increases with age and is nearly 60% in people aged 65 - 74 years. With increasing age, polymorbidity and polypharmacy usually contribute to an increasingly complex approach to manage the respective clinical conditions, including the treatment of hypertension. All subgroups of calcium channel blockers are effective and well-tolerated in lowering blood pressure. They are of demonstrated benefit for the prevention of stroke in elderly patients with systolic hypertension. Calcium channel blockers are particularly recommended for elderly patients with systolic hypertension and for black patients. The nifedipine gastrointestinal therapeutic system (GITS) formulation provides a once-daily dosing regimen with a continuous and slow release of the drug, resulting in a smooth plasma concentration/time profile. The INSIGHT study established that nifedipine GITS decreased mortality and morbidity at the same level as standard diuretic treatment in hypertensive patients with additional risk factors. A subgroup analysis showed that the long-term protective effects of nifedipine GITS extended to hypertensive patients with diabetes mellitus and with previous myocardial infarction. Two substudies of INSIGHT showed that nifedipine slowed the progression of atherosclerosis in carotid arteries (intima-media thickness) and coronary arteries (coronary calcium) as compared to diuretic.