A randomized, double-blind, placebo-controlled, parallel-group, multicenter trial of four doses of tasosartan in patients with essential hypertension. Tasosartan Investigator's Group

Size of blood pressure reduction from renal denervation: insights from meta-analysis of antihypertensive drug trials of 4,121 patients with focus on trial design: the CONVERGE report

OBJECTIVE

30 mm Hg drops in office systolic blood pressure are reported in trials of renal denervation, but ambulatory reductions are much smaller. This disparity is assumed to have a physiological basis and also be present with antihypertensive drugs.

DESIGN

We examine this office-ambulatory discrepancy through meta-analysis of drug and denervation trials, categorising by trial design.

PATIENTS (STUDIES)

31 drug trials enrolling 4121 patients and 23 renal denervation trials enrolling 720 patients met the criteria.

RESULTS

In drug trials without randomisation or blinding, pressure reductions are 5.6 mm Hg (95% CI 2.98 to 8.22 mm Hg) larger on office measurements than ambulatory blood pressure monitoring (p<0.0001). By contrast, with randomisation and blinding, office reductions are identical to ambulatory reductions (difference -0.88 mm Hg, 95% CI -3.18 to 1.43, p=0.45). For renal denervation, there are no randomised blinded trial results. In unblinded trials, office pressure drops were 27.6 mm Hg versus pretreatment, and 26.6 mm Hg versus unintervened controls. By contrast, ambulatory pressure drops averaged 15.7 mm Hg across all trials. Among those where the baseline ambulatory pressure was not the deciding factor for enrolment (avoiding regression to the mean), ambulatory drops averaged only 11.9 mm Hg.

CONCLUSIONS

Discrepancies in drug trials between office and ambulatory blood pressure reductions disappear once double-blinded placebo control is implemented. Renal denervation trials may also undergo similar evolution. We predict that as denervation trial designs gradually improve in bias-resistance, office and ambulatory pressure drops will converge. We predict that it is the office drops that will move to match the ambulatory drops, that is, not 30, but nearer 13.

Blood pressure lowering efficacy of angiotensin receptor blockers for primary hypertension

BACKGROUND

Angiotensin receptor blockers (ARBs) are widely prescribed for hypertension so it is essential to determine and compare their effects on blood pressure (BP), heart rate and withdrawals due to adverse effects (WDAE).

OBJECTIVES

To quantify the dose-related systolic and/or diastolic BP lowering efficacy of ARBs versus placebo in the treatment of primary hypertension.

SEARCH STRATEGY

We searched CENTRAL (The Cochrane Library 2007, Issue 1), MEDLINE (1966 to February 2007), EMBASE (1988 to February 2007) and reference lists of articles.

SELECTION CRITERIA

Double-blind, randomized, controlled trials evaluating the BP lowering efficacy of fixed-dose monotherapy with an ARB compared with placebo for a duration of 3 to 12 weeks in patients with primary hypertension.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed trial quality and extracted data. We contacted study authors for additional information. WDAE information was collected from the trials.

MAIN RESULTS

Forty six RCTs evaluated the dose-related trough BP lowering efficacy of 9 ARBs in 13 451 participants with a baseline BP of 156/101 mm Hg. The data do not suggest that any one ARB is better or worse at lowering BP. A dose of 1/8 or 1/4 of the manufacturers' maximum recommended daily dose (Max) achieved a BP lowering effect that was 60 to 70% of the BP lowering effect of Max. A dose of 1/2 Max achieved a BP lowering effect that was 80% of Max. ARB doses above Max did not significantly lower BP more than Max. Due to evidence of publication bias, the largest trials provide the best estimate of the trough BP lowering efficacy for ARBs as a class of drugs: -8 mm Hg for SBP and -5 mm Hg for DBP. ARBs reduced BP measured 1 to 12 hours after the dose by about 12/7 mm Hg.

AUTHORS' CONCLUSIONS

The evidence from this review suggests that there are no clinically meaningful BP lowering differences between available ARBs. The BP lowering effect of ARBs is modest and similar to ACE inhibitors as a class; the magnitude of average trough BP lowering for ARBs at maximum recommended doses and above is -8/-5 mmHg. Furthermore, 60 to 70% of this trough BP lowering effect occurs with recommended starting doses. The review did not provide a good estimate of the incidence of harms associated with ARBs because of the short duration of the trials and the lack of reporting of adverse effects in many of the trials.

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.

Efficacy of angiotensin II receptor antagonists in preventing headache: a systematic overview and meta-analysis

PURPOSE

To determine whether angiotensin II receptor antagonists prevent headaches.

METHODS

We systematically searched MEDLINE, EMBASE, the Cochrane Library, and International Pharmaceutical Abstracts for studies in which participants were randomly assigned to an angiotensin II receptor antagonist or placebo. We also contacted experts and manually reviewed all references to identify additional articles. Two reviewers independently extracted data from the studies. Discrepancies were resolved by discussion. We estimated the pooled relative risk (RR) for headache using the random-effects model and examined dose response using random-effects Bayesian logistic regression.

RESULTS

Data from 27 studies involving 12,110 patients were included in the meta-analysis. The risk of headache was about one third lower in patients taking an angiotensin II receptor antagonist than in those taking placebo (RR = 0.69; 95% confidence interval [CI]: 0.62 to 0.76; the test of heterogeneity was negative, P = 0.2). The odds ratio for having a headache per unit dose of the reference drug losartan was 0.81 (95% CI: 0.68 to 0.93).

CONCLUSION

Angiotensin II receptor antagonists appear to be effective in preventing headaches, but the mechanism of this benefit and the types of headaches that are prevented are not known. Randomized trials are warranted.

A pharmacokinetic and pharmacodynamic study of the potential drug interaction between tasosartan and atenolol in patients with stage 1 and 2 essential hypertension

The primary objective of this study was to evaluate the pharmacokinetics (PK) and pharmacodynamics (PD) of tasosartan and atenolol administered alone and concomitantly under steady-state conditions in 17 patients ages 18 to 65 years diagnosed with stage 1 to 2 essential hypertension. After a 3- to 14-day qualification period, all patients received placebo tasosartan on days--1 through 5 and 25 through 34, atenolol alone (50 mg) on days 1 through 5, atenolol (50 mg) + tasosartan (50 mg) on days 6 through 19, and tasosartan (50 mg) alone on days 20 through 24. A PK and PD evaluation of atenolol alone was performed on study day 5. On study day 19, PK and PD of both tasosartan and atenolol were assessed. PK and PD evaluation for tasosartan alone was assessed on study day 24. The coadministration of atenolol + tasosartan did not affect the pharmacokinetics of tasosartan, its major metabolite (enoltasosartan), or atenolol when compared with tasosartan or atenolol administered separately. For area under the change in diastolic blood pressure curve, the reduction was significantly greater after tasosartan + atenolol compared with that after atenolol alone (336 +/- 85 and 190 +/- 71 mmHg.24 h; p < 0.05 for combination and atenolol alone, respectively; mean +/- SEM). Combination therapy also caused a maximal reduction in diastolic blood pressure that is significantly more than with monotherapy with atenolol (-27 +/- 2 mmHg and -20 +/- 2 mmHg, respectively, p < 0.05). The additive effects of tasosartan and atenolol in decreasing diastolic blood pressure may provide a rationale for combination antihypertensive therapy.