MRC trial of treatment in elderly hypertensives

Modeling biomarker variability in joint analysis of longitudinal and time-to-event data

The role of visit-to-visit variability of a biomarker in predicting related disease has been recognized in medical science. Existing measures of biological variability are criticized for being entangled with random variability resulted from measurement error or being unreliable due to limited measurements per individual. In this article, we propose a new measure to quantify the biological variability of a biomarker by evaluating the fluctuation of each individual-specific trajectory behind longitudinal measurements. Given a mixed-effects model for longitudinal data with the mean function over time specified by cubic splines, our proposed variability measure can be mathematically expressed as a quadratic form of random effects. A Cox model is assumed for time-to-event data by incorporating the defined variability as well as the current level of the underlying longitudinal trajectory as covariates, which, together with the longitudinal model, constitutes the joint modeling framework in this article. Asymptotic properties of maximum likelihood estimators are established for the present joint model. Estimation is implemented via an Expectation-Maximization (EM) algorithm with fully exponential Laplace approximation used in E-step to reduce the computation burden due to the increase of the random effects dimension. Simulation studies are conducted to reveal the advantage of the proposed method over the two-stage method, as well as a simpler joint modeling approach which does not take into account biomarker variability. Finally, we apply our model to investigate the effect of systolic blood pressure variability on cardiovascular events in the Medical Research Council elderly trial, which is also the motivating example for this article.

Nitrendipine and Dementia: Forgotten Positive Facts?

Nowadays, there are about 50 million people suffering from dementia worldwide. In 2030, it is expected that there will be 82 million people living with dementia and in 2050, their number should reach 152 million. This increase in the number of people with dementia results in significant social and economic problems. Therefore, researchers attempt to reduce risk factors causing the development of dementia such as high blood pressure. Epidemiological studies have shown that hypertension increases the risk of dementia at an older age. It can, therefore, be assumed that hypertension therapy will reduce the risk of dementia. However, previous clinical studies have shown that the efficacy of different antihypertensive drugs differs in this respect. The drug group that appears to be the most effective in these analyses is calcium channel blockers (CCBs). The most significant preventive efficacy in terms of protection against dementia has been demonstrated with nitrendipine. Its use is, therefore, particularly advantageous in elderly patients with systolic hypertension who are at high risk of dementia. The purpose of this study is to restore the discussion on the prevention of vascular dementia and Alzheimer’s dementia with nitrendipine in indicated hypertonic patients. The authors performed a literature search of available sources describing the issue of dementia, hypertension and its treatment with nitrendipine. In addition, they made a comparison and evaluation of relevant findings. The results of the detected research studies indicate that nitrendipine is able to reduce the incidence of dementia [Alzheimer’s disease (AD), vascular and mixed] by 55%. The treatment of 1,000 patients with nitrendipine for 5 years may prevent 20 cases of dementia. However, what has not yet been explained is the temporal link between hypertension and dementia due to the long-time intervals between hypertension and the development of dementia.

Effectiveness and safety of beta blockers in the management of hypertension in older adults: a systematic review to help reduce inappropriate prescribing

BACKGROUND

The benefit from a blood pressure lowering therapy with beta blockers may not outweigh its risks, especially in older populations. The aim of this study was to look for evidence on risks and benefits of beta blockers in older adults and to use this evidence to develop recommendations for the electronic decision support tool of the PRIMA-eDS project.

METHODS

Systematic review of the literature using a stage approach with searches for systematic reviews and meta-analyses first, and individual studies only if the previous searches are inconclusive. The target population were older adults (≥65 years old) with hypertension. We included studies reporting on the effectiveness and/or safety of beta blockers on clinically relevant endpoints (e.g. mortality, cardiovascular events, and stroke) in the management of hypertension. The recommendations were developed according to the GRADE methodology.

RESULTS

Fifteen studies were included, comprising one meta-analysis, four randomized controlled trials, six secondary analyses of randomized controlled trials and four observational studies. Seven studies involved only older adults and eight studies reported subgroup analyses by age. With regard to a composite endpoint (death, stroke or myocardial infarction) beta blockers were associated with a higher risk of events then were other antihypertensive agents. Further, beta blockers showed no benefit compared to other antihypertensive agents or placebo regarding mortality. They appear to be less effective than other antihypertensive agents in reducing cardiovascular events. Contradictory results were found regarding the effect of beta blockers on stroke. None of the studies explored the effect on quality of life, hospitalisation, functional impairment/status, safety endpoints or renal failure.

CONCLUSION

The quality of current evidence to interpret the benefits of beta blockers in hypertension is rather weak. It cannot be recommended to use beta blockers in older adults as first line agent for hypertension.

Beta-Adrenergic Receptor Blockers in Hypertension: Alive and Well

Beta-adrenergic receptor blockers (β-blockers) are an appropriate treatment for patients having systemic hypertension (HTN) who have concomitant ischemic heart disease (IHD), heart failure, obstructive cardiomyopathy, aortic dissection or certain cardiac arrhythmias. β-Blockers can be used in combination with other antiHTN drugs to achieve maximal blood pressure control. Labetalol can be used in HTN emergencies and urgencies. β-Blockers may be useful in HTN patients having a hyperkinetic circulation (palpitations, tachycardia, HTN, and anxiety), migraine headache, and essential tremor. β-Blockers are highly heterogeneous with respect to various pharmacologic properties: degree of intrinsic sympathomimetic activity, membrane stabilizing activity, β₁ selectivity, α₁-adrenergic blocking effects, tissue solubility, routes of systemic elimination, potencies and duration of action, and specific properties may be important in the selection of a drug for clinical use. β-Blocker usage to reduce perioperative myocardial ischemia and cardiovascular (CV) complications may not benefit as many patients as was once hoped, and may actually cause harm in some individuals. Currently the best evidence supports perioperative β-blocker use in two patient groups: patients undergoing vascular surgery with known IHD or multiple risk factors for it, and for those patients already receiving β-blockers for known CV conditions.

Changes in selected metabolic parameters in patients over 65 receiving hydrochlorothiazide plus amiloride, atenolol or placebo in the MRC elderly trial

Background

Treatment of hypertension reduces incidence of stroke, myocardial infarction and heart failure perhaps partly by controlling different metabolic parameters. There is limited information regarding the changes in potassium, sodium, weight, cholesterol and glucose levels in patients using anti-hypertensives. This study aimed to determine changes in potassium, sodium, glucose, cholesterol, weight, urea and urate levels in patients using anti-hypertensives. Furthermore, to describe these changes and differences between the atenolol, hydrochlorothiazide plus amiloride and placebo arms of the Medical Research Council (MRC) elderly randomised controlled trial.

Methods

Patients were randomly allocated to one of the three treatment arms. Measurements were taken at baseline, end of year one and end of year two in 4396 subjects. Linear Mixed Models (LMM) were used to determine the longitudinal profiles of sodium, potassium, weight, cholesterol, glucose, urea and urate. Estimates of changes within groups and difference between groups were obtained.

Results

Patients randomised to receive hydrochlorothiazide + amiloride experienced a significantly greater mean reduction in potassium, sodium and weight compared to placebo at end of year one - mean differences in change −0.18 mmol/L, (95 % CI: −0.21, −0.15); −1.45 mmol/L, (95 % CI: −1.62, −1.29) and −0.46 kgs (95 % CI: −0.73, −0.20) respectively, and greater increases in cholesterol, urea and urate - mean differences in change 0.16 mmol/L, (95 % CI: 0.10,0.22); 0.77 mmol/L, (95 % CI: 0.68, 0.87) and 53.10 μmol/L, (95 % CI: 49.35, 56.85) respectively. Changes were in the same direction but smaller in the atenololarm except for potassium and weight (increases). No group differences in glucose were found.

Conclusion

Results were in line with expectation except for lack of change in glucose in the hydrochlorothiazide + amiloride arms.

Electronic supplementary material

The online version of this article (doi:10.1186/s12872-016-0368-2) contains supplementary material, which is available to authorized users.

The effect of antihypertensive treatment on the incidence of stroke and cognitive decline in the elderly: a meta-analysis

AIM

To evaluate the effectiveness of antihypertensives in reducing neurocognitive outcomes in elderly patients.

PATIENTS & METHODS

We conducted a systematic literature search of randomized trials in which hypertensive patients with a mean age ≥65 years received antihypertensive or control treatment. Outcomes were stroke, transient ischemic attack, cognitive decline and dementia. We included 14 trials for meta-analysis.

RESULTS

Compared to placebo, antihypertensive treatment reduced the risk of stroke (RR: 0.67 [95% CI: 0.57-0.79]). Reduced risk was significant for transient ischemic attack, fatal stroke, nonfatal stroke and total stroke. There were insufficient data to compare individual agents.

CONCLUSION

Antihypertensive treatment is associated with a significant reduction in stroke in elderly individuals. Reductions in dementia and cognitive decline were not significant; however, there was short follow-up. Comparative effectiveness evidence is limited.

Beta-blockers: no longer an option for uncomplicated hypertension

Traditionally, beta-blockers, used as first-line agents to treat uncomplicated hypertension, were recommended by national and international guidelines despite a paucity of evidence regarding their cardiovascular benefit. However, evidence from recent trials and meta-analyses has questioned the use of beta-blockers as preferred agents. This article reviews the data available from clinical trials and argues that beta-blockers are less efficacious than other currently available antihypertensive agents for patients with uncomplicated hypertension.

Applying hypertension guidelines to reduce the burden of heart failure

If the recommendations of Joint National Committee 7 are implemented, the incidence of heart failure should continue to decline. These recommendations are designed not only to reduce the incidence of heart failure but also prevent other target end-organ damage and reduce overall cardiovascular morbidity and mortality. The emphasis of these recommendations is to reduce systolic blood pressure, because the risk of mortality caused by heart disease and stroke doubles for every 20-mm Hg increase in systolic blood pressure. Practitioners are encouraged to use a combination of lifestyle changes and pharmacotherapy to achieve systolic blood pressure goals and consider the use of thiazide diuretics as first-line therapy to achieve the ultimate goal of reducing end-organ damage.

Cardiovascular protection using beta-blockers: a critical review of the evidence

For more than 3 decades, beta-blockers have been widely used in the treatment of hypertension and are still recommended as first-line agents by national and international guidelines. Recent meta-analyses indicate that, in patients with uncomplicated hypertension, compared with other antihypertensive agents, first-line therapy with beta-blockers was associated with an increased risk of stroke, especially in the elderly cohort with no benefit for the end points of all-cause mortality, cardiovascular morbidity, and mortality. In this review, we critically analyze the evidence supporting the use of beta-blockers in patients with hypertension and evaluate evidence for its role in other indications. The review of the currently available literature shows that in patients with uncomplicated hypertension, there is a paucity of data or absence of evidence to support use of beta-blockers as monotherapy or as first-line agents. Given the increased risk of stroke, their "pseudo-antihypertensive" efficacy (failure to lower central aortic pressure), lack of effect on regression of target end organ effects like left ventricular hypertrophy and endothelial dysfunction, and numerous adverse effects, the risk benefit ratio for beta-blockers is not acceptable for this indication. However, beta-blockers remain very efficacious agents for the treatment of heart failure, certain types of arrhythmia, hypertropic obstructive cardiomyopathy, and in patients with prior myocardial infarction.

Long-term safety of antihypertensive therapy

Lowering blood pressure (BP) in hypertensive patients reduces morbidity and mortality. However the long-term safety of some antihypertensive agents was a matter of concern. Diuretic, the gold standard treatment in hypertension may impair glucose tolerance and thereby accelerate the development of diabetes mellitus. It was also associated with increased cardiovascular mortality in diabetic patients. However, recent evidence showed that low-medium dose of thiazide diuretic especially when given in combination with potassium sparing agent is effective in reducing BP and cardiovascular morbidity and mortality. Beta blockers are less effective than other antihypertensive agents in the elderly. Therefore they may be appropriate as a first choice in young and middle-age hypertensives, and in those with fast heart rate, but they should not be considered appropriate as the first-line therapy in the elderly with uncomplicated hypertension. Several years ago a plethora of publications showed that short-acting calcium antagonists may increase the risk for myocardial infarction and cancer. A few years ago two studies showed that calcium antagonists are less effective than angiotensin converting enzyme inhibitors in preventing cardiovascular events in diabetic hypertensive patients. However, recent results from large prospective randomized studies showed that calcium antagonists reduce cardiovascular morbidity and mortality in diabetic and non-diabetic hypertensive patients. Some investigators have suggested that angiotensin receptor blockers (ARBs) may increase the risk of myocardial infarction in hypertensive patients. However, recent meta analyses refuted this conclusions and showed that ARBs are probably as effective as other antihypertensive agents in prevention of myocardial infarction. Despite the concern that has been raised regarding the long-term safety of some antihypertensive agents, it is clear that lowering BP is safe and beneficial.

Therapeutic Controversies in Hypertension

Although numerous prospective randomized trials since the Veterans Administration studies clearly have attested to the efficacy and safety of antihypertensive therapy, there remain some controversial issues with all classes of antihypertensive drugs. Thiazide diuretics increase the risk for new-onset diabetes and their long-term safety has been questioned. Alpha-blockers do not reduce morbidity and mortality in uncomplicated hypertension but are well known to cause a variety of poorly tolerated side effects. The safety of calcium antagonists has been questioned for many years, although recent large prospective randomized trials such as Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial, International Verapamil-Trandolapril Study, Intervention as a Goal in Hypertension, Valsartan Antihypertensive Long-Term Use Evaluation and the Anglo-Scandinavian Cardiac Outcomes Trial (ASCOT) have attested to their safety and efficacy. Angiotensin-converting enzyme inhibitors, in general, are well tolerated but have potentially fatal adverse effects in a few patients. Angiotensin-receptor blockers are exceedingly well tolerated, but may be less-efficacious antihypertensive agents than other drug classes. Most antihypertensive drug classes have an effect on new-onset diabetes that should be taken into account in patients at risk. No head-to-head comparison of combination therapy looking at efficacy and safety has been available. The long-term safety of antihypertensive therapy is documented poorly because most trials only last 4 to 6 years. Despite these drawbacks and concerns, the benefits of antihypertensive therapy clearly outweigh its potential risk.

Cardiovascular drug class specificity: β-blockers

Beta-adrenergic blockers are one of the most frequently prescribed cardiovascular drugs. Numerous beta-blockers are available for clinical use. Although these agents differ substantially, it is not clear whether (and which) differences are clinically relevant. Most of the important differences among agents reflect the relative specificity for beta1-, beta2-, and alpha-adrenergic receptors. Selection of a particular agent and target dose is probably best guided by available trial data, even though data are limited. Nonselective agents (with or without alpha-blocking properties) devoid of intrinsic sympathetic activity (ISA) are most appropriate postinfarction. Evidence exists demonstrating a mortality benefit postinfarction for propranolol, timolol, metoprolol, and, in the presence of left ventricular dysfunction, carvedilol. In the setting of heart failure, the selective agents metoprolol and bisoprolol as well as the nonselective agent carvedilol (which possesses alpha-blocking properties) have a demonstrated mortality benefit. Not all tolerated beta-blockers are associated with a survival benefit and it is probably not advisable to extrapolate benefits to all drugs with similar (although probably not identical) properties. Carvedilol may possess advantages over other beta-blockers and a possible survival advantage, suggested by the recent Carvedilol or Metoprolol European Trial (COMET), although these findings are not universally accepted. Ultimately, selection of a specific agent avoids obvious contraindications and uses trial data to guide selection and dose as long as side effects are absent or tolerable.

Why beta-blockers are not cardioprotective in elderly patients with hypertension

Despite the fact that beta-blockers have been used for the treatment of hypertension for more than 30 years, no study has shown that their use reduces morbidity and mortality in the elderly. To the contrary, the British Medical Research Council trial in the elderly documented that although blood pressure was lowered effectively and significantly by atenolol, morbidity and mortality in the beta-blocker group did not differ from that of the placebo group. Not only was beta-blocker monotherapy not effective, but patients who received the combination of beta-blockers and diuretics fared consistently worse than those on diuretics alone. beta-blockers are less effective than diuretics in lowering blood pressure, and are poorly tolerated in the elderly. The reason for their inefficacy in the elderly may be related to their inherent unfavorable effect on systemic hemodynamics and pathophysiologic findings in the arterial tree, heart, kidneys, brain, and on the metabolism of lipids and carbohydrates. Decreased beta-adrenergic responsiveness with age and comorbid conditions makes beta-blockers unattractive. Thus, they should not be considered appropriate for first-line therapy of uncomplicated hypertension in the geriatric population.

Hypertension in special populations

Essential hypertension is a common disorder, and a variety of antihypertensive drugs are available to lower blood pressure in the normal range. Identifying special subpopulations by differences in age, gender, race, and body weight has taught clinicians to be more selective in antihypertensive therapy. The rationale for this selectivity is often speculative and has not been corroborated by any hard data. It is hoped that some of the prospective, randomized trials currently in progress will throw some light on this question.